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diff --git a/old/52378-0.txt b/old/52378-0.txt deleted file mode 100644 index f32693a..0000000 --- a/old/52378-0.txt +++ /dev/null @@ -1,9499 +0,0 @@ -The Project Gutenberg EBook of Photo-engraving, Photo-etching and -Photo-lithography in Line and Half, by W. T. Wilkinson - -This eBook is for the use of anyone anywhere in the United States and most -other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms of -the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - - - -Title: Photo-engraving, Photo-etching and Photo-lithography in Line and Half-tone - Also Collotype and Heliotype - -Author: W. T. Wilkinson - -Editor: Edward L. Wilson - -Release Date: June 19, 2016 [EBook #52378] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK PHOTO-ENGRAVING *** - - - - -Produced by Chris Curnow, RichardW, and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - - - - -Photo-engraving, Photo-etching, and Photo-lithography in Line and -Half-tone; Also Collotype and Heliotype; By W. T. Wilkinson, Revised -and Enlarged by Edward L. Wilson. - - - - -[Illustration: John C. Moss, Prest. R. B. Moss, Supt. M. A. Moss, -Treasurer. J. E. Ramsey, Secretary. H. A. Jackson, Asst. Secy. - -Moss Engraving Co. 535 Pearl St., New York - -Illustrations of every Description, FOR BOOKS, NEWSPAPERS, CIRCULARS, -&c., &c. - -Send green stamp for circular. Send photograph, drawing or print, for -estimate. - -our Specialty. Fine Illustrated Circulars by our Moss-Type Process.] - -[Illustration: SPECIMEN OF “MOSS-TYPE” ENGRAVED BY THE MOSS ENGRAVING -CO., 535 PEARL STREET, NEW YORK.] - -[Illustration: SPECIMEN OF “MOSS-TYPE” ENGRAVED BY THE MOSS ENGRAVING -CO., 535 PEARL STREET, NEW YORK.] - -[Illustration: SPECIMEN OF “MOSS-TYPE” ENGRAVED BY THE MOSS ENGRAVING -CO., 535 PEARL STREET, NEW YORK.] - -[Illustration: G. CRAMER, ST. LOUIS. - -HALF-TONE ZINC ETCHING. (MOSSTYPE.) FROM A PHOTOGRAPH.] - - - - - PHOTO-ENGRAVING, PHOTO-ETCHING, - - AND - - PHOTO-LITHOGRAPHY - - IN LINE AND HALF-TONE; - - ALSO, - - COLLOTYPE AND HELIOTYPE. - - BY - - W. T. WILKINSON, - OF LONDON. - - REVISED AND ENLARGED BY - - EDWARD L. WILSON, - - EDITOR OF “THE PHILADELPHIA PHOTOGRAPHER,” AUTHOR OF “WILSON’S - PHOTOGRAPHICS,” “WILSON’S QUARTER CENTURY IN PHOTOGRAPHY,” - “PHOTOGRAPHIC MOSAICS,” ETC. - - AMERICAN (THIRD) EDITION. - - [Illustration] - - _The camera is mightier than the pen or the pencil._ - - NEW YORK: - PUBLISHED BY EDWARD L. WILSON, - NO. 853 BROADWAY. - 1888. - - - - - Entered according to Act of Congress in the year 1888, by - - EDWARD L. WILSON, - - In the office of the Librarian of Congress, at Washington, D. C. - - [Illustration] - - - - -PREFACE. - - -The many kind letters I have received from America with regard to -what must be called my first crude effort at bookmaking, prompted the -idea—after issuing a second and revised edition in England—of making an -attempt to cater for the inhabitants of Greater Britain, which, under -the able editorship of MR. EDWARD L. WILSON will, I have no doubt, meet -with approbation and be useful. I have made many important additions to -the last English edition. - -W. T. WILKINSON. - -LEICESTER, ENGLAND. - - * * * * * - -Besides revising the English edition and incorporating in proper place -such additions as I have found useful in practice, I have boiled down -the best points from current publications in France and Germany, and -added them. - -More still, with high regard for the author, I add chapters and parts -from, the _Handbuch der Chemigraphie und Photochemigraphie_, by Mr. J. -O. Mörch. Thus, I believe, this work is made complete to date. All the -rest must come to the worker, from industrious, careful practice. - -Very rapid progress has been made in photo-reproductive processes -during the past two years, and improvements are announced almost -weekly. I invite all interested to keep me informed of what they -discover. If I am supplied with the proper addresses I shall publish -and distribute what I learn. - -EDWARD L. WILSON. - -NEW YORK, May, 1888. - - - - -LIST OF ILLUSTRATIONS. - - -The Reversing Mirror . . . 10 - -The Dark-room . . . 25 - -The Plate-support . . . 37 - -The Whirler . . . 42 - -The Copying Camera . . . 67 - -Example of Zinc Etching (low) . . . 88 - -Example of Zinc Etching (high) . . . 90 - -Example of Zinc Etching (round) . . . 92 - -The Caliber-bridge . . . 93 - -The Sieve . . . 98 - -The Heating Lamp . . . 98 - -The Washing Table . . . 98 - -Example of Photo-engraving . . . 117 - -Example of Half-tone Engraving . . . 118 - -The Dusting-box . . . 124 - -The Transfer-board . . . 141 - -The Drying-oven . . . 167 - -Support for the Drying-oven . . . 168 - -Jacket for the Drying-oven . . . 168 - -Copper Tank for the Drying-oven . . . 168 - -Interior plan for the Drying-oven . . . 169 - -A New Drying-oven . . . 174 - -The Universal Copying Machine . . . 178 - - - - -CONTENTS. - - - PART I. PHOTO-ENGRAVING IN LINE. - - CHAPTER I. - APPLIANCES FOR MAKING PHOTOGRAPHIC NEGATIVES . . . 9 - - CHAPTER II. - THE WET COLLODION PROCESS . . . 11 - - CHAPTER III. - PHOTOGRAPHIC MANIPULATIONS . . . 24 - - CHAPTER IV. - APPARATUS FOR PRINTING UPON ZINC . . . 39 - - CHAPTER V. - PRINTING ON ZINC IN ALBUMEN . . . 45 - - CHAPTER VI. - PRINTING ON ZINC IN BITUMEN . . . 48 - - CHAPTER VII. - DIRECT TRANSFERS TO ZINC . . . 51 - - CHAPTER VIII. - ETCHING LINE TRANSFERS . . . 55 - - PART II. PHOTO-ENGRAVING IN HALF-TONE. - - CHAPTER I. - RETROSPECTIVE . . . 63 - - CHAPTER II. - MAKING GRAINED NEGATIVES . . . 65 - - CHAPTER III. - ETCHING IN HALF-TONE . . . 69 - - CHAPTER IV. - PRINTING FROM THE BLOCK . . . 72 - - CHAPTER V. - THE TRANSFER OF THE DRAWING, AND ITS TREATMENT - BEFORE ETCHING . . . 73 - - CHAPTER VI. - HINTS FROM ALL SOURCES . . . 94 - - PART III. PHOTO-ENGRAVING ON COPPER. - - CHAPTER I. - SUBJECTS IN LINE . . . 119 - - CHAPTER II. - HALF-TONE INTAGLIOS . . . 122 - - CHAPTER III. - HALF-TONE INTAGLIOS—(_Continued_) . . . 124 - - CHAPTER IV. - HALF-TONE INTAGLIOS. ELECTROTYPING METHODS . . . 127 - - PART IV. PHOTO-LITHOGRAPHY IN LINE. - - CHAPTER I. - PHOTO-LITHOGRAPHY IN LINE . . . 129 - - CHAPTER II. - PAPER TRANSFERS . . . 132 - - CHAPTER III. - PAPER TRANSFERS—(_Continued_) . . . 136 - - CHAPTER IV. - TOOVEY’S NEGATIVE TRANSFER PROCESS . . . 139 - - CHAPTER V. - PHOTO-LITHO. TRANSFERS . . . 140 - - PART V. PHOTO-LITHOGRAPHY IN HALF-TONE. - - CHAPTER I. - PHOTO-LITHOGRAPHY IN HALF-TONE . . . 143 - - CHAPTER II. - INK PHOTOS . . . 144 - - CHAPTER III. - HUSBAND’S PAPYROTINT PROCESS . . . 147 - - PART VI. COLLOGRAPHIC PRINTING. - - CHAPTER I. - HALF-TONE PHOTOGRAPHIC NEGATIVES . . . 151 - - CHAPTER II. - THE HELIOTYPE PROCESS . . . 152 - - CHAPTER III. - THE COLLOTYPE PROCESS . . . 163 - - CHAPTER IV. - PRINTING FROM THE COLLOTYPE PLATE . . . 171 - - CHAPTER V. - THE NEW HOME PRINTING PROCESS . . . 178 - - - - -|xv| - -INTRODUCTION. - - -The improvements made within the last twenty years in the art of -printing books have not, until recently, been kept pace with by the -methods of illustration. Wood engraving, except for high class and -expensive editions, was crude, whilst the use of engravings from copper -or steel, or of lithographs, was also restricted to short and expensive -editions. - -The introduction of the zinc-etching process, in which the picture is -first drawn in line, or stipple, or chalk, upon lithographic transfer -paper, then transferred to a plate of zinc and subjected to a process -of etching in various baths of acid water, marks a new era, replete -with great improvements in cheapness, facility of production, and -artistic results. - -This new process had scarcely been in good working order before it was -seen that great improvements might be made by enlisting photography in -its service; because in its original form it was necessary that the -design be made of the same size as the finished block, which, in many -cases, added too much to the expense. But by introducing photography, -the size of the original was of no moment; the lens could easily reduce -that, and at the same time preserve the proportions, as well as fine -down any crudity in the drawing. - -The first methods of producing a photo-transfer, were by making -a negative from the original, then paper coated with bichromated -gelatine was exposed under this negative, and the sensitive gelatine, -corresponding with the transparent portions of the negative -(representing the lines of the original), being exposed to the action -of light was made non-absorbent of water, whilst the sensitive gelatine -representing the white portion of the original being protected from the -action of light by the dark portion of the negative, still retained its -affinity for water. The consequence was that when a roller charged with -fatty ink was applied to the wet print, the exposed portions of the -gelatine took the ink, but the white portion being charged with water -rejected it, the result being a replica of the original in a fatty -ink. This was used as an ordinary lithographic transfer and could be -transferred to zinc and etched in relief. |xvi| - -Such a process was not perfect, and was not suitable for subjects which -necessarily should be to scale. So the next improvement was to place -a plain mirror between the lens and sensitive plate, so producing a -negative in its proper position as regards right and left; then from -this reversed negative a print in fatty ink could be made direct on the -zinc. - -These transfers on paper, or direct prints on the zinc, are restricted -entirely to what are generally termed “subjects in line,” such as -architectural drawings, plans, woodcuts, engravings from steel or -copper plates, or lithographs in pure line, in chalk, or in stipple. -The attainment of effect of half tones by graduated works of color, -thinner or thicker, or the smooth, delicate gradations of a photograph, -are not permissible in relief blocks of this kind, although for -short numbers this class of subject could be utilized by employing -the collotype, heliotype, or lichtdruck methods, which render the -half-tones without (visible) breaking up of the gradations. - -The next step was to perfect the various (published first in 1854 by -Fox Talbot) methods of mechanically breaking up the half-tones of a -photograph, and so giving a means whereby a photograph in all its -delicacy may be used to illustrate a letter-press article. - -Of course, during the progress of rendering photography applicable for -relief blocks, its usefulness for intaglio printing was not neglected. -And now having entered into very close competition with wood engraving -and by modification of the collotype methods, with lithography, -photography can now be used for the production of intaglio plates, in -half-tones as well as in line. - -The methods by which the above results are attained furnish the text -of the pages to follow; and as each and every method given has been -tried by the author, the reader may be satisfied that the manual is, as -claimed, _practical_. - -W. T. WILKINSON. - - - - -|9| - -PHOTO-ENGRAVING, ETCHING, AND LITHOGRAPHY. - -PART I. - -PHOTO-ENGRAVING IN LINE. - - -CHAPTER I. - -APPLIANCES FOR MAKING PHOTOGRAPHIC NEGATIVES. - -For all methods of heliographic printing a suitable photographic -negative is absolutely necessary, and to produce that negative good -apparatus and pure chemicals, used with skill and intelligence, are -indispensable. - -The studio must be well lighted, with a perfectly firm floor. The -dark-room should be kept for negative work only (the room where the -zinc printing is carried on being a separate room). There must be a -roomy sink in front of a good-sized window covered with a non-actinic -medium (yellow, not orange), such as two thicknesses of golden fabric, -so as to have plenty of light to see the progress of development by. - -The copying camera must have a long bellows and should not be less -than 12 by 10, fitted with rack-work, so as to be able to get absolute -sharpness in focussing. - -It will be a great advantage, and aid in adjusting the position on the -focussing screen of the drawings to be copied, if a vertical line be -drawn, and another horizontally, so that they bisect each other exactly -in the centre; then _from the centre_, mark and number each inch and -half inch upon each of the four arms of the cross; it can then be seen -at a glance not only that the picture is in the centre, but also that -it is about the right size. |10| - -The dark slide must be light-tight, and made strong rather than for -portability. - -The lens should be rectilinear, and should be capable of covering the -largest size plate the camera will take quite sharp to the corners. For -a 12 by 10 plate a lens with an equivalent focus of about 18 inches -will be best. - -[Illustration: Fig. 1.] - -To the lens must be fitted a reversing mirror of silvered glass, -mounted behind the lens by preference, as such a style of mounting -not only protects the surface of the mirror from the air, but keeps -extraneous light from affecting the brilliancy of the image. (Fig. 1.) - -The camera must be mounted upon a solid table fixed upon small grooved -or flanged wheels, such wheels running either upon rails fixed upon -or in grooves cut into the floor, at right angles to the wall against -which the copying board is fitted. - -The copying easel is placed perpendicularly in front of, and perfectly -parallel with, the camera. As a mirror is used, the camera is sideways -to the object, not facing it, as in copying direct. - -The easel should be so contrived that it can be raised or lowered, and -moved right and left, which double motion is managed by having the -easel double; the up and down motion should be obtained by hanging -the back portion like a window sash, the weights being exactly the -weight of the whole easel, and the pulleys over which the cords go, not -running too freely. - -At the top and bottom of the back portions of the easel are projecting -strips with a rabbet deep enough to allow the front or copying board to -slide sideways, but not loosely; this front board should be painted a -dead black with white lines in the centre from top to bottom and from -side to side, said lines being divided into inches and half inches, -from the centre, so that the drawing may be pinned in the exact centre -without trouble. - -A convenient size for a copying board is 4 feet high by 5 feet wide. - -In connection with the camera, the only thing left to describe is the -focussing cloth, which should be quite opaque, and of ample size to -exclude all extraneous light from behind when focussing. - -For focussing the image absolutely sharp, a magnifying glass may be -required. - - -|11| - -CHAPTER II. - -THE WET COLLODION PROCESS. - - -THE COLLODION. - - Alcohol 30 ounces. - Ether 40 ounces. - Schering’s Celloidin* 1-1/2 cakes. - - * Hance’s D. C. gun-cotton may be used instead of the - celloidin. - -Cut the celloidin into thin strips, or, if it be hard, break it up in a -clean mortar, and dissolve in the above mixture of alcohol and ether. -When dissolved, this forms the collodion. - - -THE IODIZER - -is composed of: - - Bromide of Zinc 150 grains. - Iodide of Zinc 350 grains. - Alcohol 10 ounces. - -When the salts are dissolved, filter and add to the collodion. - -The filtering is best done by placing a pledget of cotton-wool in the -neck of a glass funnel and passing the iodizer through it. To prevent -evaporation, lay a glass plate over the funnel. - -The iodizer being added to the collodion, shake them up thoroughly -and allow to stand for a week to settle, then decant into convenient -bottles; this collodion is ready for use in a week, but will improve -with age up to six months, after which time it should be mixed with new. - -When coating plates with collodion, it is not a wise plan to pour the -surplus from the plate back into the bottle from which it was poured. -Pour it into another, kept handy for the purpose, the contents of -which, at the end of the day’s work, empty into the stock bottle after -such a quantity as is sufficient for next day’s consumption has been -decanted into the pourer. - -The best bottle from which to pour the collodion upon the plate is the -tall capped bottle sold by the dealers as collodion pourers. |12| - - -THE NITRATE OF SILVER BATH (1). - -The silver bath is a most important factor in the production of good -negatives. It must be compounded with care and used with skill. - -To make it, dissolve 6 ounces of nitrate of silver in 10 ounces of -water, then add 10 drops of collodion, and shake up well; then add 70 -ounces of water, and let it stand all night; then filter through a -pledget of cotton-wool packed loosely in the neck of a glass funnel, -into a clean bottle or jug; then add 1 drachm of nitric acid and let -stand all night before trying. Such bottle or jug, and also the glass -funnel, must be kept solely for use with the silver bath. - -The bath holder may be an upright vessel of the ordinary pattern, -with a dipper with which to lower the plate into the solution; or it -may be a flat dish with a cover to keep out light and dust, using a -silver hook to lift the plate from the solution; if the former shape be -chosen, let the dipper be of glass, porcelain, silver wire, or of wood -soaked in melted paraffine, but on no account of ebonite, as such a -dipper will cause spots, and derange the bath sooner or later. - -If a flat dish be used, the best form is of wood lined with asphaltum, -hanging on a cradle, the lower end being a well to hold the solution; -in this form of bath the plate, after sensitizing, is drained -thoroughly before taking it out. This is a great convenience, as not -only is silver solution saved, but the dark slide will last much longer. - -The bath solution made up as above will be the right strength for -work, but as every plate sensitized therein, takes away its modicum -of silver, after a certain time it must be strengthened, as it is -essential for the production of good work that the solution be kept at -a proper strength. The best way of doing this is to add a drachm or two -of saturated solution of nitrate of silver, after each day’s work has -been done, and if the solution be worked in a flat bath, it will be as -well to pour it into a jug and filter it before using again; with an -upright holder, this filtering will only require to be done about once -or twice a week, as any particles of dust, etc., subside and have not -the same chance of falling upon the film as in a flat bath; but the -addition of the silver solution should be made, and the solution well -stirred up with the dipper. - -In course of time a silver bath will become contaminated with organic -matter from various causes, and can also be supersaturated with ether -and alcohol—with iodo-bromo or nitrate of zinc, and will either refuse -to work, or only |13| yield imperfect films and thin images. In such -cases the best plan will be to take 20 ounces of the solution, dilute -it with clean water 60 ounces, filter, and add 6 ounces of nitrate of -silver, and again filter, when a new bath will be the result. - -The silver in the rejected portion of the old bath should be -precipitated as a chloride, by the addition of a solution of common -salt, the precipitate dried and sent to a refiner, together with the -ashes of the filtering papers and blotting-paper used to drain the -plates upon, or to wipe the backs of the plates after leaving the bath -and before putting them into the dark slide. - -The silver solution named above, is suitable for negatives of subjects -in line, but for the production of negatives with delicate half -tones, such as portraits, landscapes, or of the many subjects which -are photographed direct, then it will be necessary to provide another -bath solution, made and managed in the same way, but only containing -sufficient nitric acid to just redden litmus paper, as a bath gives the -finest half-tones when nearly neutral, or only slightly acid. It should -be remembered that the deepest shadows are represented by clear glass -in the negative, to insure which would be impossible with the silver -solution inclining ever so slightly toward alkalinity. - -The nitrate of silver bath may be made up with distilled water, if -pure—that is, if the water is bona fide distilled and not merely from -waste steam; if this cannot be guaranteed, the best plan will be to get -a gallon of tap water, dissolve in it one ounce of nitrate of silver, -then add saturated solution of bicarbonate of soda, until an alkaline -reaction to litmus paper takes place, then place the lot in white glass -bottles, and expose to the action of light for three or four days. -During that time the solution will, first of all, turn black, and -then will gradually become quite clear, the organic matter—which if -not removed, would have caused trouble—falling in a black mass to the -bottom. - -Now filter the purified water and use it for compounding the nitrate of -silver bath, but do not use it for any other purpose. - -The strength of a nitrate of silver bath, for line work, should be -thirty grains of nitrate of silver to each ounce of water, and should -not be allowed to fall below twenty-five; and for half-tone negatives, -nitrate of silver should be thirty-five, and not lower than thirty -grains to the ounce. - -Be sure to keep all funnels, bottles, and dishes used for the silver -bath, separate and distinct from all others, and never use them for any -other purpose. |14| - - -THE NITRATE OF SILVER BATH (2). - -In the ancient days of photography, when, to say it was possible to -prepare a dry plate nearly as sensitive as a wet collodion plate, was -to excite the risible faculties of the audience, the above heading -might almost always be seen in the journals, and the amount of matter -written under that heading would fill many good-sized volumes. Some -writers went into the subject in a very elaborate manner, whilst others -would counsel very simple methods of preparation and management. - -The directions given above for making a bath solution for line -negatives, will, if carried out carefully and cleanly, at once yield a -solution giving good negatives. After the bath has been mixed, either -with distilled water, ordinary tap water (_in iron districts tap water -should not be used_), or water that has been sunned and filtered, as -soon as the bulk has been made up to the eighty ounces, the solution -should be put away all night before it is tried, then in the morning -filter it carefully through a pledget of cotton-wool stuffed loosely in -the neck of a perfectly clean funnel, into a perfectly clean bottle or -jug, which must be kept entirely for use of the silver solution. When -the bath solution has been filtered it should be _perfectly clear_; if -it is at all cloudy or turbid, the filtration must be repeated. - -When the solution is perfectly clear and bright, pour sufficient into -a perfectly clean porcelain, glass, or papier-maché dish, then take -a clean plate (polished, or albumenized) and coat it with collodion; -close the door of the dark-room, and when the film of collodion -is perfectly set, raise one end of the dish containing the silver -solution, place one edge of the collodionized plate against the bottom -of the upper edge of the dish, then drop the plate upon the bottom -of the dish, and at the same time lower the dish; by this means the -silver solution will flow in an even wave over the surface of the -collodionized plate; now place the cover on the dish so as to exclude -light and dust, and allow the plate to remain in the solution for five -minutes, then with a silver hook lift the plate from the solution, and -allow it to drain (remember that no light must get into the dark-room -except what is filtered through either two thicknesses of golden -fabric, or one of canary medium); when the plate has drained so that no -solution drips from it, place it into the carrier of the dark slide; -then close the dark slide and let it remain there for five minutes, -at the end of which time remove the plate to the sink, and flood it -with sufficient developer (page 17) to just cover the film; keep this -solution flowing, to and fro, over the |15| plate for the space of -two minutes, then wash it under the tap until the surface is no longer -greasy; then apply the fixing or clearing solution (page 17) until the -whole of the yellow bromo-iodide is dissolved away; again wash, and -take the plate into the daylight. - -Now comes the test; if the film is perfectly transparent, and clear as -the glass itself, the bath is all right; but if there is the slightest -deposit (which can be removed by lightly rubbing the finger along the -surface of the film), then the solution will require the addition of -a little nitric acid. After this stir it well, and after a rest of an -hour or two try again, repeat the addition of the nitric acid, and try -a plate; repeat until the film, after developing, washing, and fixing, -is perfectly clear, and free from deposit and fog. - -The bath is now in proper working order, and if reinforced after -each day’s work with a sufficient quantity of saturated solution of -nitrate of silver (filtered), kept free from contamination with other -chemicals, and carefully filtered occasionally, it will remain in good -working order for at least six months, and then may be renewed by -treating as directed on page 12. - -It will sometimes happen, notwithstanding that extreme care and -cleanliness is exercised in the management of the bath, that it will -not work properly, and the reason why cannot easily be discovered. In -such a case, steps must be taken to put the solution into working order. - -In the case of rectifying a disordered bath, there are many methods of -procedure, but the simplest, and, as a rule, the most certain method, -is to render the solution alkaline by the addition of liquor ammonia, -adding the ammonia a little at a time; then, after well shaking, test -it with red litmus paper and continue the addition of ammonia until -the red litmus paper is turned blue. In this alkaline condition the -solution should be poured into a large flat dish, and exposed to the -action of the sun. That will speedily reduce and throw down in the form -of a black precipitate, any organic matter that may be in the bath, -and at the same time the heat of the sun will cause evaporation of the -ether and alcohol left in the solution by the collodion plates. - -The bath solution should be exposed to the sun for two or three days, -or until such time as suffices to render the solution clear, and the -precipitate entirely separated out. But this cannot take place unless -the solution is decidedly alkaline, the presence of acid stopping the -action of light. - -Do not be in a hurry about doctoring a bath solution (in fact, it -will be far best to have two solutions, one in use and one either -resting or being doctored), but give the light plenty of time to -reduce the organic matter, and also to |16| volatilize the ether and -alcohol; then filter the solution through filtering paper (don’t use -blotting-paper), as if it is attempted to filter through a pledget of -cotton-wool the fine precipitate of organic matter quickly clogs the -wool and stops the filtering. - -The doctored solution being filtered, test it with a piece of perfectly -fresh, blue litmus paper, and add nitric acid, drop by drop—shaking -well between the additions of acid—until the blue litmus paper just -turns red. Do not add acid sufficient to make the litmus turn violently -red, unless the bath is for line negatives, as a bath for half-tone -negatives must be only just acid, whereas a bath for line work must -contain more acid. - -If the color of the litmus paper shows that the alkali has been -neutralized, a plate is collodionized, then immersed in the bath for -five minutes, then drained, and placed in the dark slide, or in a dark -box for five minutes, then flooded with the iron developer (page 17); -if, upon the application of this the film should turn black, add more -nitric acid, stir up thoroughly, then try again, repeating the trials -until, upon fixing the plate with the solution of cyanide of potassium, -the film of collodion is left upon the glass plate as clear as it was -before it was immersed in the silver bath. - -A little above here it is stated that less nitric acid is required in -the bath for half-tone negatives than for line work, and the question -may well be asked where may the line be drawn? The reply is that, for -half-tone work, a piece of blue litmus paper should, upon immersion -into the solution, turn red very slowly, but when the bath is required -for line negatives the blue litmus may at once indicate the presence of -acid. - -After a bath solution has been renovated in the above manner, it -should be tested for strength, either by the volumetric method (by -preference), or by means of the ordinary argentometer sold by the -dealers, and, if, after testing, the strength is shown to be too -great, dilute with a sufficiency of sunned water (page 13); and if not -sufficiently strong, add crystals of nitrate of silver to make up the -strength to thirty or thirty-five grains per ounce. - -A bath solution renovated as above, will generally be found to work -cleaner, and yield brighter negatives than a new solution, and it -will also, if carefully used, last longer; but it must be kept up to -a proper working strength by the occasional addition of a little of a -saturated solution of nitrate of silver. - -The fact that the strength of the silver solution has got too low is -shown by the presence of semi-opaque, fantastic markings near the thick -edge of the collodion film, and also in conjunction with the presence -of organic matter in |17| the deposition under the surface of the film -of an extremely fine sand-like deposit, which, in the fixed negative, -develops into myriads of pinholes in the densest portions of the image. - - -THE DEVELOPING SOLUTION. - -First purchase seven pounds of commercial sulphate of iron (copperas) -and put this into a gallon jug, and fill it up with boiling water -(clean); stir with a clean rod at short intervals for three or four -hours, then allow to stand until the sediment settles, and the top -portion of the solution is clear and bright; then decant as much as -possible into a bottle or bottles, and label “Saturated Solution of -Iron.” Then again fill up the jar with boiling water, stir until as -much as possible is dissolved, so as to be ready by the time the stock -in the bottle is exhausted, and repeat the process until all the -crystals are dissolved; then wash out the jar, reject the residue, and -begin again. - -But bear in mind that, unless there are crystals left in the solution -after each addition of hot water, it will not be saturated; therefore, -before taking the solution into use, be sure there are undissolved -crystals in the jar. - -For use, take of - - Saturated Solution of Iron 10 ounces. - Acetic Acid 4 ounces. - Water 70 ounces. - Alcohol 1 ounce to 5 as required. - -In the above solution, the alcohol is added to enable the developer to -readily assimilate with the sensitive film, and the quantity requisite -varies with the age of the silver bath, or, to be more correct, with -the quantity of plates sensitized therein. At first, little or no -alcohol will be required, but after a number of plates have been -sensitized the developer refuses to flow evenly, and seems disposed to -run over the edges of the plate; this is a sign that more alcohol is -required, and when more has been added the developer will flow evenly -as before; but when 80 ounces of developer require over 4 ounces of -alcohol to make it flow, it is a pretty sure sign that the bath wants -remaking. - -The developer is applied to the plate after exposure, from a -straight-lipped cup, or glass measure, which should be kept for the -exclusive use of this solution, as the mixture of any of the other -solutions with it will at once counteract its working power. |18| - - -THE FIXING OR CLEARING SOLUTION. - - Cyanide of Potassium 3 ounces. - Water 20 ounces. - -This solution is highly poisonous, both in solution and vapor, so it -ought to be kept in an upright holder, the plate being lowered into -the solution on a dipper; keep the solution well covered up, so as to -prevent evaporation as much as possible. - -After being in use a short time this solution will become weak and -should be strengthened by the addition in the evening of a lump or two -of cyanide and then stirred up with the dipper in the morning; the -negative must not be left in this solution too long or the density of -the film will be impaired, but must be removed and well washed directly -all the yellow iodide has been dissolved. - - -THE INTENSIFIER. - -No. 1. - - Water 80 ounces. - Chloride of Ammonium 2 ounces. - -dissolve, then add: - - Bichloride of Mercury 2 ounces. - -dissolve, and filter. - -No. 2. - - Liquor Ammonia 0.880 5 ounces. - Water 20 ounces. - -Solution No. 1 is best kept in an upright holder, as if kept in a flat -dish there is always the danger of cutting the skin with the glass -plate and getting the mercurial poison into the system. - -No. 2 is kept in a well-stoppered bottle and only sufficient for each -plate withdrawn as required. - -Another method of intensifying, for those who object to the use of -mercury, is to bleach the negative in a solution of - - Ferridcyanide of Potassium (_Red Prussiate of Potash_) 6 parts. - Nitrate of Lead 4 parts. - Water 80 parts. - -dissolve and filter. |19| - -When the plate is bleached, wash it thoroughly under the tap, taking -care that the edges and corners of the film as well as the centre are -washed, then flood it with a sufficient quantity of - - Nitric Acid 1 ounce. - Water 80 ounces. - -Allow this to remain on a few seconds, then wash, and flood with a -sufficient quantity of - - Sulphide of Ammonium 1 part. - Water 5 parts. - -which will at once turn the film an intense black; again wash, and -flood with the nitric acid solution, and again wash; then the negative -is allowed to dry. - -This method of intensifying is cheaper than the other, and if the -washes of acid between and after the other two solutions are carefully -done, and the stench of the sulphide is not objected to, then there -is little or no difference in the results; but if the acid washes -are omitted or (and) the sulphide has not been kept corked, and is -consequently not fresh, then there is great danger of a brown stain -upon the lines, which is more or less fatal to getting a good print on -zinc. - -For half-tone negatives, instead of fixing or clearing with the cyanide -of potassium, the developer is washed off directly, and then they are -intensified at once by the application of a mixture of pyrogallic acid, -citric acid, and nitrate of silver, as follows: - - No. 1 Solution of Pyrogallic Acid 40 grains. - Citric Acid 30 grains. - Water 20 ounces. - -As much of this solution as will cover the washed plate is put into a -small cup, and flowed all over the film, then returned to the cup, and -a few drops of - - Nitrate of Silver 30 grains. - Water 1 ounce. - -is added. Then the mixture is poured over the film, and rocked to and -fro for a short time; the intensifier is then returned to the cup, the -negative held up to the light, and examined, and if not intense enough, -the intensifier is again applied. Great care is requisite at this -stage, as if the process be carried on too |20| far the negative will -be too intense, and will either be spoiled, or take an abnormal time -to print; practice and observation are the only guides to success. The -grand rules for half-tone negatives are, collodion free from dust, the -glass plate clean, the bath at its full strength and in good working -order, proper time allowed the plate in the sensitizing bath, well -drained, afterward a good exposure, develop until all details are out, -then wash thoroughly, intensify with judgment, wash well, fix, and -again well wash, and then, but never till then, open the dark-room door -and examine your new negative by daylight. - -In making the collodion, soak the celloidin in the ether for about -twelve hours before adding the alcohol; be sure the ether is at least -0.725 specific gravity, and that the alcohol is very clean, and free -from gum. After mixing the collodion and iodizer, shake up well, but do -not do this before decanting. Always decant sufficient for next day’s -use, into the bottle used for pouring, over night, so that it gets a -chance to settle, and allows the air-bubbles to escape. - -Keep the collodion in as cool a place as possible, and in decanting it -be very careful to do it away from fire, or lighted gas or paraffine, -especially where flame is below the bottle, as ether vapor does not -rise, but falls. - -In hot weather and during long exposures, wet plates are very prone -to have a peculiar stain upon them, called oyster-shell markings, the -remedies for which are careful draining before putting them into the -slide, and covering the bottom of the carrier with clean filtering -paper, so that the silver solution, on draining down, is absorbed by -the bibulous paper instead of going back up the plate by capillary -attraction. - -In hot weather the back of the plate, when put into the dark slide, -should be covered with a wet piece of red blotting paper, or orange -calico, _but not white_; a wet cloth laid in the camera will also tend -to keep the plate moist. These precautions, however, are not required -unless the exposure is likely to exceed a quarter of an hour. - - -PROTECTING THE COLLODION FILM. - -A collodion film, when dry, is very delicate, and, except for line work -in the hands of an expert, will require protecting. This is usually -done by slightly warming it (when quite dry) in front of a fire, and -then pouring over a sufficient quantity of thin spirit varnish. After -the superfluous varnish is well drained off, dry by again holding it -in front of the fire. The spirit |21| varnish answers perfectly for -ordinary work, but for printing upon metal for relief blocks, or upon -glass for collotypes, it will be best to use a benzole varnish, such -as is sold by dealers for protecting the films of glass positives or -ferrotype pictures. Anthony’s “diamond” varnish is good. - -But the best plan of all is to use a water varnish, made by dissolving -half an ounce of borax in a quart of boiling water, then adding a few -pieces at a time (stirring meanwhile), one pound of ordinary shellac; -if the quantity of borax named does not suffice to make all the shellac -dissolve, add more, a grain at a time, until the shellac is dissolved; -then add half an ounce of white sugar, cool and filter it. - -When the negative is washed for the last time, allow it to drain, then -flood with the above solution, and let it dry. This will be found -a quicker, cleaner, and more satisfactory method of protecting the -delicate film than with the spirit varnish. - - -THE GLASS PLATE. - -_The glass_ used as a support for the collodion film should be thin -flatted crown of the best quality, for the negatives, as a rule, are -not required again after once the zinc is etched, so that the film may -be washed off, and the glass used again, which cannot be done so often -if the glass be of bad quality; flatness is a _sine qua non_, as it has -to be subjected to heavy pressure between a zinc plate and the front -glass of a printing frame. - -As a good and suitable negative is the foundation of success in -the subsequent processes, so is a properly cleaned glass plate the -foundation of a successful negative; unless the glass is chemically -clean, the collodion film will either be stained or marked, or it -will split off in drying, therefore care and attention are requisite; -even in preparing a piece of glass for the reception of the film of -collodion care is especially requisite, as the want of it cannot be -seen until after all the operations, therefore the labor and time are -not thrown away. - -There are two methods of cleaning the glass plate: one quite -mechanical; the other is a mixture of the mechanical and the chemical. -Both are good. The second is perhaps the best, as it is simple and more -certain. - -In the first method the glass, when new, merely requires polishing with -clean wash leather kept for this purpose. - -The best way of doing this is on a flat board 24 by 18 inches, or -thereabouts, |22| covered with good American oil-cloth, glazed side -out. A plate laid upon this will not slip about when being polished. - -Both sides and edges of the plate must be well cleaned, as one of the -most prolific causes of derangement of the silver bath is from organic -matter introduced by imperfectly cleaned glass plates. - -One side of the plate, if gently rubbed with the thumb nail, will be -found smoother than the other, and is the suitable side for the support -of the collodion film; this side is polished with the leather until, -upon breathing gently upon it, the film of moisture is quite free from -marks or streaks, not only in the centre but at the sides and corners. - -It is absolutely necessary that the plate be chemically clean all over, -else the film of collodion, upon drying, will split, and the negative -be spoilt. - -When the plate is clean, an edging of India-rubber dissolved in -benzole, about an eighth of an inch wide, is run all round the edge, -by means of a small camel’s-hair brush tied to a stick, the end of the -stick being level with the point of the brush. The stick acts as a -guard against the brush going too far from the edge. - -In the second method, the new glass plate is soaked an hour or two in a -mixture of 5 ounces of common spirits of salt (hydrochloric acid) in 80 -ounces of water. After both sides of the plate are rubbed with a rag, -and well washed under the tap, it is put in a dish of clean water. When -all the plates have been so treated, they are taken out singly, again -well rubbed on both sides with another rag, and well washed; then the -smoothest side having been selected, it is twice flooded with a mixture -of albumen and water, draining the surplus into the sink each time of -flooding. The plate is then placed upon a rack to drain and dry; the -drying should be effected in a current of hot air freed from all dust. - -The albumen mixture is composed of the white of one egg well beaten, -then diluted with 40 ounces of water and ten drops of liquor ammonia -added, and again beaten. It must then be very carefully filtered -through cotton-wool, and used as above. - -In placing the albumenized plates upon the drying rack, care must -be taken to face the coated sides all one way, as when dry there is -nothing to indicate to the eye which is the back and which the front. - -The albumenized plates, when dry, should have the backs cleaned with a -cloth or a leather before using, so as to clear away any albumen which -may have adhered during coating. |23| - -Albumenized plates stored in a dry place will keep good for months, -_and do not require any edging with India-rubber_, as the most horny -collodion film will not split off an albumenized plate. - -Glass plates that have been used, and not varnished, are freed from the -films by being immersed in a mixture of hydrochloric acid and water for -a few hours, then washed under the tap, well rubbed with a rag, and -put into clean water, from which they are taken singly and coated with -albumen; or they may be allowed to dry, and are then polished by means -of the wash leather. - -Negatives that have been varnished are cleaned by first immersing in -a hot solution of common washing soda until the film comes off, then -wash them under the tap, rubbing well with a rag, then immerse them in -the acid solution so as to neutralize the alkali. Finally they may be -treated as above. - -The films that are removed from the glass plates must not be thrown -away, but should be carefully collected, dried, and sent to a refiner -with the other silver waste; a good plan for saving these films, and -at the same time keeping the acid and soda solutions clear of them, is -to filter each solution occasionally through an old felt hat suspended -conveniently over the tanks, using one for each of the tanks. - -The polishing of the glass plate must not be done in the dark-room, -or the crop of comets, spots, etc., upon the negatives will be -exasperating in the extreme; let this operation be conducted in a -clean, quiet corner of the studio, where no other operation will -disturb, and where the fluff from dusters and leathers will not -interfere with anything else. - - -|24| - -CHAPTER III. - -PHOTOGRAPHIC MANIPULATIONS. - -The chemicals being prepared, they must be placed in the dark-room; the -collodion bottle should be placed on a convenient shelf close to the -door, and on a handy peg hang a broad camel’s-or badger-hair brush, for -dusting the clean plate just previous to coating it with collodion; the -brush must not be used for anything else upon any pretence whatever. -The silver bath must be kept, both in use and out of use, in some -convenient corner, where there is no risk of getting any other chemical -splashed into it. For a bath holder a deep 15 by 12 porcelain or papier -maché dish, with a wooden or stout cardboard lid, should be provided, -and this dish must always be thoroughly washed, and wiped dry with a -clean damp leather (kept for the purpose), both before use and after -pouring the silver solution back into its bottle or jug. Or, if the -upright form be preferred, be sure and have it large enough. - -The developer should be placed on a shelf, on the right of the sink, -the developing cup close by. - -The fixing or clearing solution should be kept in an upright bath of -glass, porcelain, or ebonite. - -The intensifier No. 1 may be kept in a flat dish, or in an upright -holder, at discretion; but if in a flat dish, the solution should be -poured back into its bottle, after each day’s work. - -Keep the intensifier No. 2 in a stoppered bottle close to the sink. - -The water varnish also is kept in a bottle or jug. - -On a shelf close to the collodion, the polished or albumenized plates -may be stacked, with the clean or prepared side facing the wall. - -A pneumatic holder for attaching to the back of the plate during the -operation of coating with collodion will be found very handy. - -Of course, it is thoroughly understood that there is a sink in the -dark-room, and a good water supply is indispensable. - -Then, again, the window through which the light is transmitted, must -be |25| covered with a non-actinic medium, such as two thicknesses of -golden fabric, or one of canary medium; do not stint the amount of -light, but have as much as possible, so long as it is non-actinic. - -No arbitrary plan for the dark-room need be followed, but the novice -will find the annexed plan useful to him in contriving for himself. It -is self-explanatory. - -[Illustration: Fig. 2.] - -Everything being in readiness, we will now proceed to make a line -negative, reserving a description of half-tone work to follow. - -To begin: wash the bath holder thoroughly, and wipe it dry, then pour -into it sufficient silver solution to make the depth about half an -inch; dust the inside of the cover, and put it over the dish; now take -a clean glass plate, if it be polished, see that it is edged with -India-rubber, and if albumenized, be sure and clean the back—and attach -it to a pneumatic holder; then with a broad camel’s-or badger-hair -brush (kept for this purpose only) remove any particles of dust, -back and front; now hold the plate in a horizontal position and pour -upon it, toward the right hand corner furthest away from the body, a -little more collodion than it is judged will be sufficient to cover -it; let the collodion run to the corner, then incline the plate to the -left, and the collodion will run into the upper left-hand corner. Now -by inclining the plate toward the body the collodion will flow into -the lower left-hand corner, and thence it is guided into the funnel -placed in the bottle prepared for its reception; during the time that -this surplus is draining, the plate must be gently rocked sideways, -so that the lines formed by the collodion, in draining, are merged, -leaving the film quite homogeneous. As soon as the collodion ceases -to drip, release the plate from the pneumatic |26| holder, and touch -the lower ridge of the collodion; if it is quite set, close the door -of the dark-room, remove the lid from the bath holder, then—holding -the plate in the left hand—with the right hand raise the end of the -bath holder, as far as is possible without risking any of the silver -solution running over the end of the dish resting on the bench; now -lay the plate (with the collodion side up) on the bottom of the dish, -then drop the plate into the solution, and, at the same time, lower the -end of the dish held up by the right hand, which will cause the silver -solution to flow in one even wave over the collodionized surface. This -operation must be done with dexterity, as if the silver solution does -not flow in an even wave the film will be marked, and, in the case -of a half-tone negative, the image will be spoilt. Therefore, it is -necessary to see that the plate and dish are lowered simultaneously, so -that the solution goes over the collodion film in one steady wave. If -the upright bath holder be used, the plate is placed upon the ledge of -the dipper, and lowered slowly and steadily into the solution. - -The plate will require an immersion of about three minutes for proper -sensitizing, and this interval—the bath being covered up to prevent -the access of white light—may be utilized to give the final adjustment -to the camera, and to see that the drawing or print to be copied is -properly in focus. - -Use a medium diaphragm in the lens for focussing, and examine the -image all over before deciding that it is sharp. Focus by preference -about halfway between the centre of the picture and the edges, and -then, after moving the rack to and fro until the proper sharpness is -obtained, take out the diaphragm and substitute the smallest sent out -with the lens; or if the picture to be taken be small and from a large -original, then the second, or third, smallest diaphragm may be used. - -Now remove the focussing screen from the camera (note that the ground -side of the glass has been next the lens) and place the cap upon -the lens; close the door of the dark-room, open the dark slide, see -that the proper carrier is in it, then raise the plate from the bath -slowly, using a silver-wire hook for the purpose. If the solution flows -evenly over the film, the plate is ready; but if, on the contrary, -the solution flows greasy, then again lower the plate and rock the -dish gently for a minute or two. The film being fully sensitized, the -plate is carefully lifted out of the solution, both hands holding -the plate in such a manner as to avoid touching the film; allow the -solution to drain from the plate as much as possible, then lean the -plate against the wall, the lower end resting upon a pad of clean -blotting-paper, so as to catch any further draining; |27| now with a -pad of blotting-paper or papier-joseph wipe the back of the plate as -dry as possible; this will prevent stains, and keep the dark slide from -rotting by the action of the silver solution. - -The plate being drained, lay a piece of thin filtering paper in each -lower corner of the carrier, so that the plate will rest upon the -filtering paper, which will catch any further drainings from the film, -and be a safeguard against stains. - -Now lay the plate face down in the carrier of the dark slide, close the -door, and fasten it. - -The dark slide is now carried to the camera, and inserted in the -grooves previously occupied by the focussing screen, taking care that -the sliding shutter is next the inside of the camera; when pushed quite -home, cover the back with the focussing cloth; pull out the shutter, -when the plate is ready for the exposure. - -The time of exposure will vary very much with the time of the year, and -with the amount of light falling upon the object being photographed. -The exact time can be found out only by actual practice, but the -operator, in time, by observation, will be able to guess it pretty -correctly. - -In taking the cap off the lens, be sure that the camera is not shaken, -else the picture will be spoilt. - -The exposure being made, close the sliding shutter, remove the slide -to the dark-room, and close the door; lay the dark slide (with sliding -shutter down) upon the bench, open the back shutter, and, placing the -pneumatic holder in the centre of the plate, lift it out of the carrier. - -Take the plate to the sink, and holding it face up, in the left hand, -take the developing cup in the right, and, with a quick motion, -pour over the plate sufficient developer to cover the whole film; -the developer must go all over the film in one even wave, for any -hesitation in this will result in a stain; pour upon the film only -sufficient to cover it, and be careful to spill as little as possible -into the sink, or else the image will be thin, on account of the -absence of free silver washed off by the wave of developer. - -Now rock the plate gently, so as to keep the developer flowing to and -fro over the film (but keep it there, don’t spill it off) and the -image will soon appear, faint at first, but growing gradually darker, -the black lines of the drawing being white and the white paper black. -If the development be continued too long the lines will eventually -be veiled; therefore, as soon as the finest details are out and well -defined, place the plate under the tap and allow |28| the water to -well sluice the film all over; as soon as it is properly washed, which -can be seen by the water flowing evenly over, without greasy looking -lines, hold the negative up in front of the window, and examine for -spots or stains. If there be any present that at all interfere with the -picture, at once reject the negative, placing it in a pan filled with -water, to be washed off at leisure. Then start afresh. - -The negative being satisfactory, give it another rinse under the tap, -and place it in the cyanide bath, where the unaltered iodide will -speedily be dissolved. Then it is withdrawn, and well washed under -the tap. Whilst the water is washing over the front, rub the back -with the fingers or a sponge, and then turn the plate over and allow -the water to wash the back also. It is now ready for immersion in the -intensifier No. 1, where it remains until the film is bleached almost -white. Then it is thoroughly washed, drained, and flooded with a small -quantity of intensifier No. 2, which will at once turn the film to an -intense black, or if the action does not penetrate through to the back -of the film, continue the application until it does; again wash, then -place the negative on a rack to drain. When the water ceases to drip, -flood the plate twice with the filtered water varnish. Then place the -negative on the rack to dry. When dry, it is ready for printing on -zinc. The negative may be varnished with a benzole varnish, sold by -the dealers under the name of positive or ferrotype varnish. Negative -varnish may be used, but unless very thin it is apt to be sticky and -render the negative easily marked by the heavy pressure it is subjected -to in the printing-frame. - -Now lay the finished negative face down upon a piece of clean white -paper, when, if it is a good one, all the details of the original will -show through, clearly and distinctly; but if any of the details are -missing or veiled over, the negative will not do, and another must be -made. - -This process does not always work satisfactorily, but with care and -cleanliness no serious fault should arise. - -Sometimes the bath may give what are called foggy images, which are -indicated by a veil over the lines. These can often be wiped off with -a pledget of cotton-wool. The addition of half a drachm of nitric acid -to the eighty ounces of bath solution, thorough mixing, and a rest for -a few hours, will end this difficulty. If the dark-room window be not -of the proper color, fog will ensue; therefore, the non-photographic -experimentalist had better call in the aid of a professional -photographer in case of any difficulty in getting clear negatives. - -_Wilson’s Photographics_ will be a profitable investment, as it was -published |29| before the advent of dry-plate photography, when the -wet process reigned supreme. - -At the end of each day’s work the silver solution should be carefully -poured into the jug or bottle, and allowed to stand all night; then in -the morning, just before using, it should be filtered. The dish also -must be carefully washed out and put away in a corner where it has no -chance of being soiled. - -Such are the manipulations necessary for the production of a negative -from a line subject—_i. e._, a drawing in black and white, in which the -whole of the picture is obtained by means of lines, or stipple, or by -cross hatching. Flat washes of color not being permissible, all effects -of half tones, etc., are obtained by lines, either thicker, or thinner, -or closer, or further apart. Such a negative is available for printing -from, direct upon zinc, in either albumen or in bitumen, for etching -into relief, or for printing from as a lithograph. - - -THE USE OF GELATINE DRY PLATES IN PHOTO-ENGRAVING. - -For making negatives for collographic printing either direct or by -transfer, gelatine dry plates may be used with as much certainty as the -wet collodion, so long as the operator can produce a result giving all -the gradations of tone, from the deepest shadow to the highest light; -and as there are so many excellent brands of plates in the market, -it would be worse than useless to name any brand here as having any -distinct advantage over the rest, more especially as the brand that -the writer would be inclined to name, would perhaps, by the majority -of readers, be classed as a plate that they could not work. This being -so, for half-tone negatives, the author leaves the choice of the plate -and the manner of working to the operator, contenting himself with -saying that the criterion of suitability of a negative for yielding -good results by any of the processes treated of in this book, leaving -out of the question entirely negatives for line work, etc. (treated of -in Parts I., II., and III.), is the same for giving soft, delicate, and -brilliant prints, either in platinum, carbon, or on albumenized paper, -resting assured that a negative yielding a hard black and white, or a -dirty flat print, by any of these three methods, will not give results -any different in collographic or transfer methods. - -For line work negatives for printing upon zinc, for etching, or for -transfers to stone, ordinary gelatine dry plates are not useful, as -it is almost impossible to get that freedom from veil over the lines -that it is absolutely necessary to have; here the wet collodion is best -as it is simplest, easiest, and cheapest. |30| Still there are times -when the most ardent wet-plate worker is obliged to confess that the -process has its shortcomings, most especially in dull weather, when it -is necessary, to get the result required, to give exposures from thirty -to sixty minutes; then, what with the plate drying and the want of -pluck from the bad light, it is impossible to get a result suitable for -the work. In this case the plate called the “Process” plate is a great -boon. It is fairly rapid, and gives intense negatives, without veil on -the lines. - -For making transparencies same size of original negatives, the best -plan is to place a large sheet of white paper in front of the copying -camera, and rack the lens out of focus, taking care that the white -sheet of paper is sufficient to illuminate the full size of the plate. -Then in the dark-room place the negative in the carrier of the dark -slide, film side up, and carefully dust the surface (also seeing that -the back of the negative is clean) with a clean camel’s-hair brush; -dust also the film of a gelatine dry plate, and place it face down -upon the negative, close the slide, and insert it into the grooves of -the camera and expose to the light reflected through the lens from the -white sheet of paper for from five to twenty seconds, according to the -density of the negative and the intensity of the light; close the lens -and the shutter, and remove it into the dark-room for development. - -By exposing a plate in this manner there is a far better chance of -getting absolute contact between the two plates, as the rays of light -are parallel. - -For making transparencies for printing upon copper-plates, first of all -make a grained negative the proper size, then when this is varnished -and touched up, make from it as above a transparency upon a gelatine -chloride dry plate, by which process it is more certain to get a -suitable result for the process than on a gelatine bromide dry plate. - -No formula will be given here for developing these gelatine chloride -plates as each packet has full instructions for development which must -be followed implicitly. - -For developing gelatine bromide dry plates for negatives, or for -transparencies, the following, a modification of the Ilford formula, -will be found better than using formula where the ammonia and bromide -are mixed together. - - -_Solution No. 1._ - - Pyrogallic Acid 1 ounce. - Meta Bisulphate of Potash 1 ounce. - Bromide of Potassium 1 ounce. - Water 80 ounces. |31| - - - _Solution No. 2._ - - Liquor Ammonia 1/2 ounce. - Water 10 ounces. - -For a normal exposure equal parts of these are mixed just before using, -and for an uncertain exposure begin with two parts of No. 1, one part -of water, and one part of No. 2. - - -THE REPRODUCTION OF NEGATIVES. - -For the production of suitable collotype prints, the first -consideration is the negative, from which the printing surface is to -be made. The requirements are, a negative in which all the half-tones, -both in the lights and in the shadows, are reproduced in their proper -gradations; the lights must not be too dense, or the shadows too clear; -the blackest portion of the negative must be that part representing -the highest light, and the only clear glass, that which represents the -deepest shadow; these negatives may be either wet collodion, or on -ordinary gelatine-bromide plates and reversed—_i. e._, the mirror must -be used behind the lens. If it is desired to produce a collographic -block from a negative already in existence, and which may not be -retaken, then it will be necessary to make another negative. This may -be done in many different ways; but whichever way is adopted, the first -and most important step is the production of a transparent positive. - -This transparent positive may be made on an ordinary gelatine-bromide -plate, or on a gelatine-chloride plate, and then from the transparent -positive a negative is made by transmitted light (in the enlarging -camera), either the same size, reduced or enlarged in size; or instead -of using this class of transparency, by far the finest results can be -got by making the transparency in carbon tissue, which can be used for -both transmitted light, for enlarging or reduction in size, and it can -also be used for contact printing, when the reproduced and reversed -negative is required to be the same size as the original. - -On page 29 directions are given for the manipulations when gelatine dry -plates are used, so here we will confine ourselves to the production -of negatives from the carbon transparency. First of all, procure some -carbon transparency tissue, ready sensitized, cut this into sizes at -least half an inch larger all round than the negative, then cut a brown -paper mask to fit all round the negative, and to protect the margin -of tissue from the action of light; this acts as a safe edge to the -tissue, enabling it to adhere to the glass support during the operation -of development. If it is only intended to reproduce a portion of the -|32| original negative, the safe edge may be made by putting the mask -just round that portion of the image, but if the whole of the negative -is required, put it in a printing frame with a plate glass front, fix -the brown paper mask outside the negative, then place the sensitive -carbon tissue the black side next the negative film, and put in the -backing, and back, and fasten it up. Next expose it to the light for -four or five times the time requisite to get an ordinary silver print. - -The carbon tissue having been exposed to light for the proper time, it -is taken into the dark-room, the edges are turned up so as to form a -dish, and pinned upon a small board; it is now coated with thin plain -collodion, the surplus being poured into a bottle kept for the purpose, -and the board gently rocked to and fro, so as to prevent the collodion -running in ridges, or streaks. Now allow the collodion to dry, then -place the coated and exposed tissue in clean cold water until it is -quite limp, then slide underneath it a gelatinized glass plate a little -larger all round than the tissue, bring the gelatinized surface of the -glass plate and the collodionized surface of exposed tissue in contact -under the water, taking great care not to abrade the collodion; then -lift the two out and lay the glass down upon a bench, and cover it over -with a piece of thin India-rubber, or mackintosh, or oil-cloth. Hold -the cover firmly on the bench with the left hand; with the right use a -strong squeegee vigorously. That will expel all the water from between -the two surfaces (collodion on the tissue, and gelatine on the glass), -and so bring them into absolute contact; now remove the cover, lift the -plate and examine the tissue through the glass, and if there are no -air-bells between the two surfaces the operation has been successful; -but if air-bells are present, _at once_ plunge the plate into cold -water, strip off the tissue, and try again, but be careful to be quick -about it, or there is a risk of the tissue absorbing too much water, in -which case great difficulty will be experienced in getting it to lie -flat upon the gelatinized glass. - -The gelatinized plate upon which the exposed and collodionized tissue -is mounted is prepared as follows: Glass plates free from scratches and -stains, are placed in a weak mixture of hydrochloric acid and water, -and rubbed with a clean rag until free from grease and dirt; they are -then washed under the tap, and whilst wet are covered with: - - Gelatine 1 ounce. - Water 20 ounces. - Bichromate of Potash 15 grains. |33| - -Soak the gelatine in the cold water until it is soft, then melt at -gentle heat, add the bichromate, and when dissolved, filter, and coat -the cleaned plate two or three times, throwing the surplus away each -time of coating; now stand the coated plate on a rack to dry. Any -quantity of these plates may be prepared at a time, and used when -required. When all the batch has been coated, the rack may be removed -into a warm corner, free from dust, until the plates are dry, then -expose the plates to the light for at least twenty minutes, when -they are ready for use for mounting the exposed and collodionized -transparency tissue upon. - -After the tissue is mounted upon the glass plate, it is allowed to -stand a few minutes, then it is placed in a dish containing hot water -(100° F.), and as soon as the tissue compound shows signs of dissolving -by exuding from under the paper, lift the paper away, then rock the -dish, and, if necessary, add more hot water; then raise the plate and -gently lave it with the hot water, until the whole of the soluble -pigmented gelatine is washed away, leaving a transparent positive on -the glass, which merely requires washing under the cold water tap, and -drying, to be finished. Now examine it closely, and if it contains the -whole of the details in the negative, and is free from dust spots, it -may be put away to dry, but if underexposed, or overexposed, or marred -by spots not in the original, then another must be done; but if care is -taken to dust the surface of the tissue, and the film of the negative -with a camel’s-hair brush before printing, and before collodionizing, -and also to see that both the collodion and the gelatine mixture are -properly filtered, and that the water in which the coated and exposed -tissue is soaked is free from dirt, then there will be no difficulty in -getting a perfect transparency. - -The transparency being obtained, if it is desired to make a negative -larger or smaller than the original, the transparency is placed in the -enlarging camera with the carbon film inside, and the negative made the -requisite size, either on a dry plate or on a wet collodion plate. - -If a negative the same size is required, the transparency is placed -face up in the carrier of the dark slide, and the surface dusted; then -take a dry plate, and having also dusted its film, place it face down -in contact with the transparency, then close the dark slide and remove -it to the camera, which should be previously adjusted opposite a large -sheet of white paper; now put in the dark slide, draw the shutter, and -expose to the sheet of paper, and develop as directed on page 30. - -By exposing in this manner, instead of direct to the light (day or -gas), the |34| rays projected through the lens fall upon the dry plate -quite parallel, so securing sharp negatives. - -In making reversed negatives for collographic printing when wet -collodion is used, it is not absolutely necessary to use the mirror, as -they may be made upon polished glass (_i. e._, not albumenized) dried, -then coated with gelatine, again dried, and stripped. - -Some brands of dry plates can also be stripped, by first of all, after -drying, coating them with India-rubber solution, then with collodion, -and soaking in dilute fluoric acid; but great care and patience must -be exercised, the preliminary trials being made upon negatives of no -particular value. - - -STRIPPING COLLODION FILMS. - -Negatives made by the wet collodion process can be easily stripped -from the glass support, and in such a condition are extremely handy, -especially for printing on collographic plates, or on zinc or copper, -as, the film being flexible, contact is more easily secured. - -When it is intended to strip the film, the glass plate must be -polished, _not albumenized_, and after the negative is dried, strips -of thick paper are pasted along the four sides of the negative, with -starch, or a solution of gum tragacanth; the negative is then placed -on a levelling stand and a sufficient quantity of the following warm -solution of gelatine is poured upon the plate (which should be slightly -warmed first) and spread all over it by means of a glass rod: - - Gelatine 2-1/2 ounces. - Sugar 1-1/2 ounces. - Water 20 ounces. - -Soak the gelatine in the water until soft, melt by gentle heat, then -strain through two or three thicknesses of fine muslin, and pour upon -the plate, using three ounces for a plate 12 × 10; more or less, in -proportion for different sizes. The plate must be allowed to stay upon -the levelling stand until the gelatine has quite set, then put it on a -rack to dry, in a current of cold air, for if heat be used the gelatine -will melt. - -When the gelatine is _quite dry_, pass the blade of a penknife all -around underneath the strips of thick paper, when the negative film may -be lifted away from the plate. - -In this condition the negative may be stored away without risk of being -broken, the only condition being, it must be kept free from dampness. -|35| - -Another plan of stripping is to coat the dry negative with a thick -solution of India-rubber in benzole, and allow it to dry on a levelling -stand; then coat with a thick plain collodion, to which a few drops of -castor oil have been added. When the collodion film is quite dry, place -the plate in a dish of clean water, strip off the film from the glass, -then place the film between sheets of clean blotting-paper to dry, or -it may be allowed to dry on the plate. - -Old collodion negatives that have been varnished may be stripped, but -it is rather a risky operation, and should never be attempted until a -really good carbon transparency has first been obtained. - -The first step will be to remove the varnish, which is effected by -soaking the plate in - - Alcohol 1 part. - Ammonia 1 drachm. - -until all the varnish is removed, then rinse in alcohol, wash well -under the tap, dry, paste slips of brown paper around the margin, and -finally level and cover with the warm gelatine, dry and strip. - - -THE REVERSING MIRROR. - -The mirror is a piece of perfectly plane glass, coated on the surface -with a thick film of pure silver, and highly polished. This silvered -glass must be mounted in a mahogany box, and fitted on the front of the -camera, the lens being fitted in front of the mirror, see Fig. 1. This -mirror is placed in grooves at an angle of forty-five degrees from the -axis of the lens. So situated, it receives the image projected by the -lens, and reflects it on the focussing screen, or sensitive plate in -the camera. By this means a negative is obtained, which, when looked -through with the film between the operator and the glass, will present -the image in its proper position, whereas, if the lens be used without -the intervention of the mirror it will be necessary to have the glass -between the eyes and the film, to get the image in its proper position, -and as the generality of photographic negatives are taken without the -intervention of the mirror, they are called ordinary negatives in -contradistinction to those made through the mirror, which are called -“reversed” negatives. - -The silver surface of the mirror requires great care and attention to -preserve its lustre. If tarnished, it will make the exposure in the -camera longer, besides which, the cost of resilvering is too great to -allow of the surface being spoiled through carelessness. |36| - -At the end of each day’s work, remove the mirror from the box and warm -it in front of the fire (not over a gas flame) just slightly, then wrap -it carefully in a piece of fine velvet, which has also been previously -warmed, then wrap it up in a piece of India-rubber or macintosh cloth, -and put it in an air-tight box; by doing this, the mirror, if well -silvered at first, will last for a year or two. - -If the surface should become tarnished, get a square of very fine -chamois leather, and place in the centre a pellet of cotton-wool; then -gather up the leather and tie the wool in the centre, making a small -globe about an inch and a half in diameter; now warm the mirror, and -after dipping the leather globe into fine rouge, proceed to polish -gently with a quick circular motion, using little or no pressure—take -care in doing this that the mirror, the leather, and the rouge are -quite dry, else the silver coat will come away—_verb sap_. - -In purchasing a mirror be sure and get it large enough to take the cone -of rays from the lens it has to be used with; for a lens three inches -in diameter, the plane mirror should measure about 8 × 3-1/2 inches. - -The box to hold this mirror should be made square at the side, fitting -into the rabbet of the camera front, so that when objects are to be -photographed that will do better lying on the ground than when fixed -against the wall, the mirror can be placed to look down upon the object. - -For silvering the glass, one cannot do better than to quote the -directions for working Common’s process given by Major Waterhouse in -the _Photographic News_. - -“The solutions recommended by Mr. Common are three: - - (1) Nitrate of Silver 1 ounce. - Distilled Water 10 ounces. - (2) Caustic Potash 1 ounce. - Distilled Water 10 ounces. - (3) Glucose 1/2 ounce. - Distilled Water 10 ounces. - -The above quantities are suitable for 250 square inches, consequently, -an ordinary copy mirror 8 × 6 would require rather more than two ounces -of each solution, and other sizes in proportion. - -The caustic potash and distilled water must be quite pure. Ordinary -caustic potash will not answer at all. The best to use is known as -_pure by alcohol_. - -The glass surface to be silvered is carefully cleaned with strong -nitric acid, applied, as recommended by Mr. Browning, with a Buckle’s -brush, then well |37| washed in clean water, and after rinsing with -distilled water, laid, face downward, in a dish of distilled water -until wanted. - -Before cleaning the glass, it will be necessary to arrange for -supporting it face downward in the depositing dish, so that the surface -to be silvered may be quite horizontal, and just below the level of the -fluid, which should be about half an inch above the bottom of the dish. - -I have generally used a large cork, about four inches in diameter, -cemented to the back of the plate, and fitted with three strings, by -which it could be suspended in a level position and adjusted to any -height by winding the string over a roller placed at a convenient -height above the dish. When this arrangement is not available, I fix on -the back of the plate two ordinary wide-mouthed bottle corks of equal -thickness, in the positions shown in the figure, and to these corks -attach thin slips of bamboo running transversely across the plate, and -of sufficient length to rest on the sides of the dish, thus: - -[Illustration: Fig. 3.] - -The slips of bamboo give the arrangement a certain amount of spring, by -which the height of the plate can easily be regulated, by putting on -weights until the surface of the plate is just below the level of the -fluid in the dish. - -To prepare the silvering solution: A sufficient quantity of the -silver solution, No. 1 (two ounces), is put into a perfectly clean -glass. Ammonia is dropped in until the precipitate first formed is -just redissolved. The same quantity of potash solution, No. 2, as of -silver is now mixed in, and the precipitate again dissolved by ammonia. -A little more silver solution is then added to produce a distinct -turbidity, and distilled water to make up the quantity necessary to -fill the depositing dish to about three-eighths or half an inch, and -the mixture is then filtered through cotton into another clean glass -vessel. - -The same quantity (two ounces), of filtered solution of glucose, No. -3, as was taken of silver and potash, is now mixed in, and the whole -is poured into a depositing dish (which should preferably be of glass, -well cleaned with nitric acid). - -The glass plate is then taken out of the distilled water and laid -face downward on the silvering solution, being supported, as before -described, just above the surface, so that the solution does not cover -its back. - -Mr. Common places the requisite quantity of distilled water in the dish -in |38| which the mirror has been remaining face downward, and then, -having lifted the mirror up, pours in the undiluted silvering solution, -together with the glucose solution, stirs well together, and then -carefully lowers the mirror again into the dish. - -Almost immediately after the immersion of the plate, the silvering -action begins, and, if things are going on well, a brilliant reflecting -surface will be seen at the back of the plate, and in forty minutes, -or even less, a good deposit of silver will be obtained. It is usually -recommended to stop the action as soon as the silvering fluid appears -clear and free from turbidity, but it is not always easy to see this. - -After silvering, the plate is well washed, finishing with distilled -water, and dried off quickly. A slight cloudiness of the surface may -appear, and must be removed by polishing before the mirror can be -used. It is better to allow the mirror to remain a day or so before -polishing, in order to harden the coating. - -To polish the plate, it should be slightly warmed, and perfectly dry, -and rubbed very gently in small circles with a piece of very soft and -dry chamois leather, afterward using a little jewellers’ rouge. - -Mirrors should always be kept in a dry place, and will require -repolishing from time to time. - - -|39| - -CHAPTER IV. - -APPARATUS FOR PRINTING UPON ZINC. - -A suitable negative (the subject being in line, _not half tone_) having -been obtained, the next stage toward producing a relief block is to -make from that negative a print in ink upon a sheet of zinc. To do this -a sheet of polished zinc is first of all subjected to the action of a -solution of nitric acid, alum, and water. It is then thoroughly washed, -placed in a machine called a whirler, then coated with a solution of -albumen (white of egg) and bichromate of potash; this coat or film of -bichromated albumen should be dried over a spirit lamp. - -The negative is then placed, face uppermost, in a printing-frame, the -coated side of the zinc in contact with the face of the negative. The -negative is now exposed to the action of light. - -The exposure being complete, the frame is taken into a room lighted -by yellow light, gas, or lamp-light, the zinc plate is removed, and -its surface covered with a thin film of transfer ink, by means of a -type-printer’s roller; then the zinc plate is immersed in clean cold -water and the image developed by gently rubbing it with a pledget of -cotton-wool. - - -POLISHING THE ZINC. - -Zinc plates suitable for photo-engraving can be obtained either in -large sheets, or cut to size as ordered, and, when new, require -polishing with a damp rag dipped in levigated pumice powder—_i. e._, -pumice powder washed in water, so as to get rid of all grit. - -Lay the plate upon a board covered with muslin and polish with a -“from-and-to” the body motion, not circular; do not use a great deal -of pressure, the object being to get the plate highly polished with a -perfectly smooth surface. - -Plates that have been printed upon, and are not satisfactory, may be -cleaned and repolished. - -Plates that are scratched require polishing with emery cloth. Scratches -interfere with the picture. |40| - -To remove scratches, sprinkle the face of the plate with turpentine, -then rub with a piece of FF emery cloth stretched over a carpenter’s -cork-covered rubber. Use the same motion, to-and-fro, until all the -turpentine has evaporated and the surface of the zinc is polished. If -the scratches are removed, the plate is ready for use, but if not, -then the operation must be repeated. If the scratches are too deep for -emery cloth alone, first use a piece of fine pumice stone, followed -by snake stone, pumice powder, rotten-stone, and rouge. Too much care -cannot be taken with the zinc plate at this stage, for, after the block -is etched, if it is discovered that the plate has not been properly -polished, all will have to be done over again, entailing a loss of -time, labor, and materials. - -Remember, that no matter what polishing agent is used, the plate must -be polished with a to-and-fro from the body motion, not a circular -motion such as is usual in polishing metal. - - -GRAINING THE PLATE. - -The next operation is to give the plate a slight tooth so that the -sensitive solution will flow evenly over the surface. Do this by -removing all traces of grease. - -This graining is done in a wooden tray, 24 inches by 18 by 6, lined -with asphaltum or gutta percha and mounted upon rockers; it is quite -necessary that the graining tray be of large size, as if only a little -larger than the plate the returning wave of acid water will mark the -edges of the zinc. - -Into this tray pour a quart of clean water, and add one drachm of -nitric acid and one ounce of a saturated solution of common alum. Place -the plate in this, face up, and commence rocking it at once or else -the acid will mark the surface, and it will require repolishing; rock -slowly for five minutes, during which time the polished surface will -give way to a fine matt, like fine frosted silver. Now remove the plate -and rinse it under the tap, rubbing it gently with a fine sponge, or a -pledget of cotton to remove the scum or deposit formed by the acid. The -surface at this stage should be quite smooth; if it is at all rough, -the acid is too strong, and the solution must be diluted with water; if -the action of the acid is very slow, then a little more must be added; -but it will only be necessary to add more alum when the plate is a -bluish color instead of being a pearly gray. - -A drop or two of acid will be required each time plates are to be -grained. - -In rubbing with sponge, or a pledget of cotton when under the tap, care -|41| must be taken not to scratch the surface of the zinc, or else it -will need repolishing. - - -COATING THE PLATE WITH SENSITIVE ALBUMEN. - -If the solution of albumen was poured over the plate and drained and -dried, the film would be too thick at the bottom and too thin at the -top; it is, therefore, necessary, to insure an even film of sensitive -albumen, to subject the plate to a quick circular motion, so as to -spread the film of albumen evenly, and to get rid of the surplus -solution. This is effected by placing the grained zinc in the jaws of -an instrument called a whirler and made as follows: - -Two pieces of wood, each half an inch thick, twelve inches long, nine -inches wide at one end, and six inches at the other; upon the narrow -end of one piece fix four screws, a piece of iron the shape of a ┻, -the top end of which is shaped to fit into the socket of a carpenter’s -brace (which must have the centre handle revolving, not fixed); the -cross piece must be flat, and pierced with four holes, countersunk to -admit of stout screws. - -Place the two pieces of wood together, the ┻ piece between the two, -and with a piece of stout leather hinge the two together, nailing the -leather not only on the outside, but upon the top also; now screw a -narrow batten on each of the pieces, about an inch from the widest end, -to keep the wood from warping. - -Four inches from the top (the hinge being the top) bore a hole through -both pieces, and pass through a couple of strong leather laces; by -one end fix these on the outside of the cheek to which the iron ┻ is -screwed, and on the outside of the other cheek, seven inches from the -top, hinge a piece of wood (so as to fall toward the bottom) 5 inches -by 2 by 1/2; and in the centre of the batten screwed on to prevent -warping, fix a broad-headed nail or a turn-button, over which the free -end of the leather laces can be passed. - -Now about half an inch from each end drive through the wood, six or -eight wire nails one inch long in a line, and so that the points -project on the inside of each cheek. Next fix the top of the iron into -the socket of the brace and the whirler is ready for use. - -To use this instrument, lay it upon the bench, raise the upper jaw, -place the grained zinc behind the teeth (face out) close the jaw, -and after seeing that the face of the zinc is close up to the teeth, -tighten the shoe lace, pass it over the hinged piece (which is lying -down close to the cheek), and around the batten with two or three -turns, then pass it back and tie the loose ends around the iron shank -at the top; then raise the hinged piece, which by straining on the |42| -leather laces will cause the jaws to grip the zinc plate tight and -hold it in position. (See Fig. 4.) - -[Illustration: Fig. 4. The Whirler.] - -Now lift up the whirler from the bench, grasping the handle of the -brace firmly in the right hand. Hold it at arm’s length, and by a -series of quick jerks set the plate revolving. This will require a -little patience to do evenly and rapidly, but with practice it will -become quite easy. - -The plate is coated twice, whirling it after each application of the -sensitive mixture. The whirler is then laid upon the bench, and the -hinge piece let down. This relaxes the strain upon the leather laces, -and allows the jaw to be lifted and the plate removed. - -An inverted revolving egg-beater may be made to serve for the same -purpose. - - -DRYING THE COATED ZINC. - -The film of albumen now requires drying, which should be done over a -spirit lamp. The best form of lamp is one of the small pocket spirit -stoves sold by ironmongers, and having the three supports for a kettle -cut away. The zinc is held over the flame and kept in constant motion, -so as to dry the film as quickly and evenly as possible; no fear need -be felt at applying too great a heat so long as the metal can be held -comfortably in the fingers. When dry, the plate is ready for printing -upon. - -For drying large plates, two or more of these stoves would be required, -but it is very easy to extemporize a suitable arrangement, by laying a -large pad of cotton saturated with spirits of wine in a tin dish, and -setting it on fire; by this means a stove of any desired dimensions can -be prepared quickly. To extinguish such a flame, cover it with a large -sheet of zinc. - -It must be borne in mind that the film on the zinc is now very -sensitive to |43| light, therefore the preparation of the film must be -done in a yellow light, as must also the operation of placing it in the -printing-frame, inking up, and development; gas or lamp light may be -used, as the film is not sensitive to artificial light of a low actinic -power. - - -THE PRINTING FRAME. - -The printing-frames used for this purpose must be of the box pattern, -fitted with stout plate-glass fronts, the cross bars behind being -fitted with wooden screws, instead of springs, as absolute contact can -only be obtained between the surfaces of the glass negative and zinc -plate by means of screw-pressure. - -The front glass of the printing-frame must be kept perfectly clean, and -especial care must be taken that no grit be upon either glass, inside -the frame, or on the back of the negative, else the negative will be -broken. - - -TIMING AND EXPOSURE. - -The time of exposure to light is measured by means of an actinometer, -which is simply an instrument in which is a strip of sensitive -paper, exposed under a graduated series of different thicknesses of -translucent paper, each division or gradation being distinguished by a -number, thus: No. 1 has only one thickness of paper over it; No. 2, two -thicknesses, and so on. But on account of the ever varying intensity -of the light, a screen actinometer that is reliable is almost an -impossibility. The best must be closely watched in a bright light, so -that the tints are changed evenly. - -Johnson’s actinometer is very simple and handy; it consists of a -cubical box with two lids, the inner one serving to press the paper in -contact with the glass of the outer lid; the outer lid has a circular -opening with a narrow rectangular strip in the centre transparent, -the rest of the glass being covered with pigment the color assumed by -the sensitive paper after exposure to the light. When the strip of -sensitive paper inside has assumed this color, it is called one tint; -the strip of paper is then pulled forward, and another portion, quite -white is brought under the transparent portion of glass, and when the -light has turned that the color of the pigment, that counts two tints, -and so on. The paper used in the actinometer is ordinary albumenized -paper. - -The exposure of zinc in the printing-frame under a good line negative, -will be about six or eight tints in diffused light, but in direct -sunlight the exposure may be timed by the watch, a suitable line -negative never requiring more than from three to five minutes. |44| - - -INKING THE EXPOSED ZINC. - -The sensitive zinc having been exposed to light under the negative, -next cover the surface with a thin coating of litho-transfer ink, stone -to stone. - -For this purpose we require a type-printer’s composition roller, -mounted upon a litho stock. This roller must be perfectly smooth and -cast in a solid mould, as the line along the side, formed by a split -mould would render it useless for inking up a zinc plate. A roller -eight inches long by five or six inches in diameter is a useful -size. We also require an inking slab, a palette knife, a bottle of -turpentine, with the cork cut so that the turpentine can be sprinkled -out without having to remove the cork, a tin of transfer ink, and a -linen cloth or two. - -The inking slab may be made of smooth iron, or a suitable lithographic -stone is good. - - -|45| - -CHAPTER V. - -PRINTING ON THE ZINC IN ALBUMEN. - -The negative being ready for printing, select a piece of zinc a little -larger each way than the picture, polish, then grain, and after well -washing it under the tap and gently rubbing it with a fine sponge, or -a pledget of cotton-wool, place it in the whirler; again rinse under -the tap, now invert the whirler and set it revolving; then examine the -surface of the zinc and see that there is no dirt on the surface, but -that it is quite smooth. If it is not, rinse it again under the tap, -and rub it gently with the sponge, and again rinse. This should quite -free the zinc from any deposit of dirt. Now whirl it so as to get rid -of as much as possible of the water, then pour over the surface of -the zinc sufficient to cover it, of the following solution (carefully -filtered through cotton-wool): - - Albumen of one Egg. - Water 7 ounces. - Saturated Solution of Bichromate of Potash 1 ounce. - -Place the white of egg in a bottle containing a lot of small pieces -of perfectly clean glass, then add the water and shake it well for a -minute; then add the solution of bichromate and again shake it well. -Now place a pledget of cotton-wool in the neck of a glass funnel, and -pass a few ounces of clean water through (if this is not done, there -will be difficulty in getting the albumen to filter); drain as much as -possible of the water away, and then filter the albumen into a clean -bottle; when all the solution has gone through, remove the cotton-wool -from the funnel, which well wash, then recharge with a fresh pledget, -pass some water through, and again filter the albumen solution through, -this time into a ten ounce glass-measure, which is to be used for -pouring from upon the zinc. The stem of the funnel should be long -enough to reach the bottom of the glass measure, so that the formation -of air-bubbles be avoided, which is impossible with albumen if the -funnel is not below the surface of the filtrate. - -Of this, pour over the zinc sufficient to well cover the surface, -letting any surplus go into the sink; then set the whirler revolving, -coat again, and |46| again whirl; now examine the surface, and if it -is free from dust, spots, and air-bubbles, remove the zinc and dry it -over the spirit stove. But if either air-bubbles or dust be present, -wash them off under the tap, and begin again. - -The film being dry, get the printing frame ready, see that the surface -of the glass inside is quite clean and free from grit, as also the back -of the negative, taking special care that the ridge of varnish which -often forms at the bottom of the negative be removed, as the slightest -inequality of surface will surely cause disaster directly the screws -exert their pressure. - -Do not lay the negative into the frame flat upon the glass, but slide -it in from one side, so as to carry any dust away from the glass front -of the printing frame. - -The negative being in the frame, film side up, lay the coated zinc upon -it, face down, judging the proper position and placing the zinc flat -down upon the negative; now put a piece of brown paper over the back of -the zinc, then place the back of the printing frame in place, fasten -down the cross bars and apply the pressure screws, evenly and gently. - -Do not screw one side tight before the other has been touched, but -screw down so as to tighten all as evenly as possible. - -Even pressure being applied, see that the front of the frame is clean, -and then expose to direct sunlight for five minutes. Remove the frame -to the dark-room, unfasten the cross bars and remove the zinc, taking -great care to avoid scratching its film against the film of the -negative. - -After wiping the inking slab with clean linen place a piece of the -transfer ink, about the size of a small bean, upon the upper corner, -sprinkle this with a little turpentine, and mix them with the palette -knife until they are of about the consistency of printing ink. - -Now with the palette knife spread some of this mixture as far as -possible over the inking slab, and then distribute it with the -composition roller. Roll to and fro, across and diagonally, until -there is a thin, even coating of ink all over the slab (not touching -the corner where the ink was mixed with the turpentine) and upon the -roller; if the mixture is too dry and refuses to spread, sprinkle on a -little more turpentine, but do not use too much, else it will take a -long time to evaporate. - -The roller having a coat of rather moist ink spread evenly upon it, -place the exposed zinc, face up, on a piece of clean white paper, and -proceed to roll it briskly to and fro, using a moderate amount of -pressure, until the whole of the turpentine has evaporated; it should -leave a thin coat of ink with an even |47| matt surface, not thick -enough to quite hide the yellow film of the sensitive albumen, as, if -it does hide it, too much has been put on, and it will most likely -smear in development. - -If, after first applying the roller, the ink on the zinc seems likely -to be too thick, at once wipe the roller dry, and then roll the zinc -briskly until the coat of ink is perfectly even and the turpentine -evaporated. - -At this stage everything depends upon getting the coat of ink even. -If there are patches of thick and patches of thin, sprinkle some -turpentine upon the slab, quickly charge the roller, and roll up the -zinc again, until the coat of ink is thin and even. - -An even coat of ink being obtained, the zinc is laid in a tray -containing clean cold water of a sufficient depth to well cover the -surface. Now take a pledget of cotton-wool and rub the surface gently, -when the ink covering the albumen protected from light by the black -portions of the negative, will wash away, leaving the picture on the -zinc in ink; if the finer details do not develop easily, continue the -rubbing with the cotton-wool, but be careful not to rub so hard as to -scratch the ink lines. - -All details being developed, rinse the picture under the tap and put it -away to dry, which at ordinary temperature will take but a few minutes. - -The chances of failure in this portion of the process are, first of -all, air bubbles and dust spots in the film. These will at once declare -themselves. The remedy, is increased care and cleanliness. - -If, upon development, some of the lines are missing, then the zinc and -the negative have not been in actual contact, or if the finer lines -wash away easily, then the exposure has not been long enough; whilst if -it has been too long, either the finer details are covered up or the -whole refuses to part with any ink. - -A satisfactory print, showing all the lines of the original having been -obtained, dry, by first blotting off the water, then by gentle heat, -after which the zinc is ready for the etching room. - - -|48| - -CHAPTER VI. - -PRINTING ON ZINC IN BITUMEN. - -The process described in the previous chapter is most suitable for -printing on zinc, for blocks that are not overburthened with fine -lines, and is intended for rough printing; and also, when from want -of sunlight, and the exigencies of business, the exposure has to be -made by electric light; but when the subjects are very fine, and the -blocks must be of the very best, it will be better to print the image -in bitumen; then the first etching can be done without having to ink -up previous to immersing in the acid bath (which must be done after -developing the inked albumen image), so getting the sharpest possible -results, and also securing better depth to close work than when the -inking up has to be done before biting in. - -Now the generally accepted idea of bitumen is, that it requires such -a long exposure to light as to be practically useless, except for -direct sun printing; but that only stands good where the bitumen is not -prepared properly and where too thick a film is used upon the plate. - -By preparing the bitumen as described below and taking care to have a -very thin film of the sensitive bitumen upon the zinc plate, then the -exposure either to sunlight or electric light is not more than double -that of albumen. - -There is one especial virtue in a bitumen film. If by chance too -much exposure to light has been given, a prolonged immersion in the -developing liquid (turpentine) will remedy the defect, whereas if an -albumen image be over-exposed it is quite spoiled, and the work must be -done again. - -We are still upon the subject of line work, and the same class of -negative desirable for printing on an albumen film is necessary for -printing upon bitumen, viz., the lines must be clear glass without -veil, and the rest of the negative must be sufficiently opaque to stop -the passage of light. - -The sensitive solution of bitumen is made by procuring a small quantity -of photographic bitumen or asphaltum, and powdering it in a clean, -dry mortar. Next take a clean and dry glass beaker, half filled with -methylated ether, and pour into it the powdered bitumen, stirring with -a glass rod for a few minutes; now cover the beaker with a piece of -thin sheet India-rubber, and upon that |49| place a piece of plate -glass, so as to make the vessel as nearly air-tight as possible. Allow -to stand a few hours, then stir up again, and again allow to stand, -this time all night. Then pour away the ether, draining the liquid -as closely as possible, so as to get rid of all those constituents -which are soluble in the ether. Now add some more fresh ether, stir -thoroughly, and again allow to stand and settle, putting on the cover -as before, so as to prevent evaporation. After again settling, the -ether is poured off, and all liquid and semi-liquid matter carefully -drained away. More ether is added, and the operation is repeated -until the added ether, after standing all night, is nearly or quite -colorless. The residue in the beaker is removed to a glass plate and -spread out over its surface, so that any ether remaining may quickly -evaporate. During this evaporation of the ether, the bitumen must be -protected from the action of white light. - -By thus purifying with ether we get rid of those constituents of the -bitumen which are not sensitive to light, and thus we secure a film of -bitumen sensitive to the action of light. - -When the ether has evaporated, take of the residue half an ounce and -dissolve it in pure benzole (free from water) fifteen ounces, allow it -to stand all night, then filter it through filtering paper (placing a -sheet of glass over the funnel to prevent evaporation). It will keep -six months. - -New zinc plates will require polishing first with rotten stone, and -finishing with rouge, but plates that have been used should be first -polished with fine emery cloth, followed by pumice powder, then by -rotten stone, and finished with rouge, remembering that a circular -motion must not be used. - -If, after polishing, the surface is at all greasy, immerse it in the -graining bath used for the albumenized plates, wash well and rub away -the scum; then with a perfectly clean piece of blotting paper, remove -the water from the surface and dry it over the spirit flame. - -To coat a piece of zinc with bitumen, place it in the whirler, and -when fixed in position, dust the surface with a clean camel’s-hair -brush; then flow over it sufficient of the filtered bitumen solution -in benzole, then lower the whirler and set it in motion; whirl rapidly -for about a minute. This will equalize the coat or film of bitumen -and get rid of superfluous solution. When taken from the whirler the -plate will be ready at once for the printing frame. These plates do not -deteriorate, and a stock of them may be prepared and stored away in the -dark till wanted. Great care must be taken not to allow the slightest -ray of daylight to fall upon them, else the action once set up, will -continue, and spoil the plate. |50| - -On examining the zinc plate after removing it from the whirler, it -will be difficult to realize that there is really a sufficient film of -bitumen on the zinc, but there will be quite sufficient. - -In printing upon bitumen from negatives that have been varnished, it -will be as well to rub the varnished surface of the negative with a -pledget of cotton dipped in dry French chalk. - -The same care in putting into the printing frame, as enjoined in the -chapter on zinc printing with bichromated albumen, is requisite with -these plates, as is also the applying the pressure by means of the -screws. The exposure to light will vary from ten minutes in the sun, to -two or three hours in the shade. - - -DEVELOPING THE IMAGE. - -To develop, place the exposed plate, face up, in a shallow tin tray, -and pour into the tray sufficient turpentine to cover the plate; rock -the tray so as to keep the solution in motion, and (if the exposure -has been right) the image will gradually make its appearance; the -bitumen protected from the action of light by the dense portions of -the negative gradually dissolves away. As the development approaches -completion, great care must be used, and when the last detail is -visible, remove the plate, and rinse it with water from a rose top; -now, if the image is quite perfect, immerse the plate at once in a -mixture of nitric acid and water, the acid being just strong enough to -taste. Keep the tray containing this acid solution rocking for about -a minute, then remove the plate, and wash it thoroughly, rubbing it -very gently with cotton-wool. If the exposure under the negative has -been barely sufficient, the image will be too delicate for touching, so -before rubbing it with the cotton-wool, try some portion of the margin, -and if that stands the friction, it is all right; if not, be content -with rinsing with water. - -The immersion in the acid water will have removed the shiny appearance -of the zinc, and the matt surface will enable the operator to see if -all the requisite details of the image are visible. If not, and they -are covered with bitumen, another immersion in the turpentine will -complete the development; but if any of the lines are rotten or the -details are dissolved away, the exposure has been too short, and the -plate will require repolishing and another exposure. - -The image being satisfactory, the water is blotted off with clean -blotting paper and allowed to dry. _Don’t use heat for drying._ It may -then be exposed to light for a few minutes. This is not absolutely -necessary, although it tends to make the image finer. The plate is now -ready for etching in relief. - - -|51| - -CHAPTER VII. - -DIRECT TRANSFERS TO ZINC. - -We have now treated of the various stages necessary to obtain a -photographic transfer upon zinc, from a drawing or engraving, in line, -in dot, or in stipple, first by making therefrom, in the camera, a -negative—same size, reduced, or enlarged—and from that negative a print -on zinc, either in ink on an albumen basis, or in bitumen. - -These transfers can be used, either for yielding re-transfers for -lithographic press, or (as is at present our intention) for etching -into relief, for use as blocks for printing from letter-press. - -Before proceeding to instruction for etching these photographic -transfers into relief, we will consider the method of dealing with the -direct transfer of drawings, in line or chalk, to zinc, without the -intervention of photography. - -For direct transfers to zinc, the picture is drawn by the artist -the exact dimensions of the finished block; if in line, on ordinary -lithographic writing transfer paper, in ordinary lithographic writing -ink, just in the same way that an ordinary line subject is treated for -ordinary lithography. - -If the subject is in chalk, it may be drawn on a grained lithographic -stone, which is rolled up, etched, washed out, again rolled up, then -the transfer is pulled; or the picture may be drawn upon specially -prepared transfer paper, like Josz’s polygraphic transfer paper, or -other grained paper made for the purpose; or the subject may already -be on stone, as a lithograph, or it may be a copper-plate engraving, -in which case transfers are pulled and then put down upon zinc in the -ordinary way. - -In making drawings on lithographic transfer paper, great care must be -taken to avoid touching the surface with the fingers, as finger-marks -will transfer and roll up black. In line work all lines must be firm -and black; no attempt must be made to get effect by using thin or pale -ink. - -In chalk work, also, the drawing must be firm and strong, and the -corrections and alterations made on the transfer, not left to be done -on the stone. If the corrections or alterations are small, they may be -removed with an ink eraser, or by careful washing with turpentine, so -that all the chalk is removed; if the |52| correction be large, paste -a piece of clean transfer paper over the place, spreading the paste as -thin as possible; gum must not be used. - -The drawing on transfer paper being obtained, the next step is to -transfer it to stone; then, after rolling up and proving, another -transfer is made, which is to zinc. - -From an engraved copper plate a transfer is made on India or upon -Scotch transfer paper, on either a copper-plate press or a lithographic -press, and then transferred direct to the zinc. - -The engraved copper plate is first of all examined to see that all the -old ink is out of the lines; if not, wash with turpentine and wipe -quite dry; then, in a piece of clean linen rag, tie up some plate -re-transfer ink; warm the copper plate, either on the hot plate or over -a Bunsen burner, until it can be barely held in the hand; then, holding -it in a piece of cloth to protect the fingers, rub in the ink tied up -in the linen rag, until sufficient is melted to well cover the surface, -taking care to see that the ink is rubbed well into the lines. Then -take a piece of clean, soft rag and wipe off the ink from the surface -of the plate carefully, so as not to remove it from the reversed lines; -this is best secured by wiping across the lines, not with them. When -the surface of the plate is quite free from ink, rub the lower part of -the palm of the hand upon a ball of whiting, and proceed to polish the -surface of the plate. Do not get too much whiting upon the hand, else -it may stick to the ink and prevent it adhering to the transfer paper. - -Now place a piece of clean transfer paper (India or Scotch), a little -larger than the plate, face downward upon a piece of clean paper, -sponge the back with a damp sponge, then let it lie a few minutes, so -as to get evenly damp all through. - -Now see that the press is ready. If a copper-plate press is to be used, -see that the bed is free from grit, and that the blankets are in place; -if a lithographic press is to be used, put in a stone, wipe it free -from grit, and see that the scraper is all right; remove the tympan if -of leather, but if of zinc or millboard it is all right. Now put the -inked and polished copper plate upon the stone, and the damp transfer -paper, face down, upon the copper plate; then upon the transfer paper -place a piece of printer’s blanket, turn down the tympan, or put a -piece of thin millboard over the blanket, run the bed of the press -under the scraper, turn down the lever, and, if necessary, adjust the -pressure (a good nip is necessary), then run the bed through; now raise -the lever, pull out the bed, lift the tympan and blanket, reverse -the plate, and pull |53| through again. Now gently warm the plate, -and carefully lift away the transfer paper, which should contain the -picture with every line firm and sharp; if it is not so, sufficient -pressure has not been used, or the transfer paper has been made too -damp, or sufficient ink has not been put into the lines. - -The transfer, either drawn in line or in chalk, or from a plate, being -obtained, it is next transferred to a polished litho stone. Of course, -the picture can be at once transferred to the zinc which it is intended -to etch, but it will be found best to first of all transfer to stone, -then from the stone pull a transfer, and transfer that to the zinc, -so that in case of an accident during the etching another plate can -be quickly prepared. Before placing them upon the stone, the prepared -transfers should lie in a damping book until evenly damp. - -Now take a polished litho stone and place it in front of a fire or -in the sun until it is quite dry, then place it upon the bed of the -press, and adjust the pressure; then place the transfer upon the stone -in such a manner that it lies without any slurring. Next place a piece -of clean paper upon the transfer, then the blanket, lower the tympan, -run in the carriage, lower the lever, and pull through; then lift the -lever, draw back the carriage, turn the stone round and pull through -again, then sponge the back of the transfer with water and pull through -again, repeating the damping, and pulling through three or four times. -Now with a wet sponge saturate the back of the transfer with water, and -lift away the paper, then wash away the composition, leaving the image -on the stone; now cover it with thick gum solution, and allow it to dry. - -If more than one transfer is in hand at a time, they are trimmed as -closely as possible and pasted with very thin paste close together -upon a large piece of paper, and then all can be transferred at one -operation. - -The gum upon the stone being dry, wash it off carefully with clean -water, then roll up with transfer ink. Clean away any dirt there may -be with sponge and snake stone; where the snake stone cannot be used, -a piece of pointed wood, dipped into acid gum, will clear way the -dirt. Take care to have the wet sponge handy so as to prevent the acid -spreading upon the work; now roll up as strong as possible, then etch, -by passing over water acidulated with nitric acid of such a strength -that it just slightly effervesces when the stone is touched; saturate -a sponge with the weak acidulated water and go gently over the stone, -then with another sponge charged with clean water, wash off the acid. -Now again roll up with transfer ink as strong as possible, and pull -the transfer. Chalk drawings are transferred to stone in the same way, -then etched, but the acid water is allowed to act a little longer than -for a line transfer, and after |54| washing away the etching solution, -the picture is washed out with clean turpentine, then wiped with a -sponge, gummed in, fanned dry, moistened with a wet sponge, and the -water removed. Then the image is rolled up with transfer ink, and the -transfers pulled for subsequent etching. - -To transfer to zinc, take a piece of polished zinc and immerse it in -the graining bath (page 40) for about a minute; then remove it, wash -it under the tap, and rub it with soft sponge; then wipe it dry with a -soft rag, and warm the plate slightly; lay it upon a litho stone in the -press, lay the transfer (which has been lying in the damping book) upon -the zinc plate; lay upon the transfer the piece of blanket, lower the -tympan and pull through; then damp the back of the transfer, pull it -through again; then reverse the plate, dampen the back of the transfer, -pull through again; again dampen the back of the transfer, and again -pull through; now saturate the transfer with water, peel off the paper, -remove the composition, and apply with a sponge a sufficiency of a -solution of gum (thickness of cream), 5 ounces; decoction of nutgalls, -10 ounces. The decoction of nutgalls is made as directed on page 56. - -Allow this to stay on the zinc for about a minute, then wash off, -cover with plain gum, fan dry, and dip a sponge in gum and rub over -the plate; now dip a soft rag into the gum, then into the etching ink -(page 57) mixed with a little cocoanut oil or mutton fat and middle -varnish, continuing the application of gum and ink until the whole of -the picture is sharp, black, and strong. Be sure and keep the plate -well covered with gum and the ink as thick as possible. - -The plate is now dusted with finely powdered resin, sponged with a wet -sponge, and then is placed in the etching trough containing water and -just sufficient nitric acid to taste; in this the plate remains about -half a minute, rocking the etching trough gently all the time; now -remove the plate, wash it under the tap, rubbing gently back and front -with a sponge, then dry by gentle heat; next coat the back, edges, and -margin and portions of the front which are too large to etch away, with -thin shellac varnish. When dry proceed to etch as directed in the next -chapter. - -Instead of inking up with the rag after etching with the acid gum, wash -off, then roll up with a leather roller charged with the etching ink -mixed with a little cocoanut oil, and used as stiff as it is possible -to work it, until the image has taken in all possible, damping the zinc -with a sponge directly it shows any signs of getting dry; then dampen -slightly, and repeat as above. Next immerse it in the etching bath as -before; wash well, and dry; coat the back, edges and margin on the -front with shellac varnish, when the plate will be ready for etching. - - -|55| - -CHAPTER VIII. - -ETCHING LINE TRANSFERS. - -For etching transfers on zinc, whether photographic or direct, we shall -require the following apparatus: A slab of iron about 24 × 18 inches -and 1/2 or 1 inch thick, supported horizontally upon four legs, and -heated by an atmospheric burner, arranged somewhat like a gridiron so -that the heat is even all over. A set of rollers on litho stock, one -of leather, one of flannel, and one or two glazed rollers, the same as -lithographers use for tint printing—we also require an etching box—_i. -e._, a wooden tray, 30 × 24 inches, and 8 inches deep, well made of -seasoned wood, lined with either pitch (with a little tallow added), or -gutta-percha, and mounted upon rockers. - -This box will require a firm table for its support during the etching, -said table standing as close as convenient to a sink and water tap. - -The other requisites used during etching, are, nitric acid, turpentine, -gum Arabic of a good quality, some powdered nutgalls, three or four -sponges, some finely powdered resin, a flat camel’s-hair brush, a -solution of shellac in spirits of wine, and the following inks: - -First the etching ink, composed of beeswax one-quarter ounce, Russian -tallow two ounces, bitumen half an ounce, middle varnish two ounces. - -Melt these together in a pan over a fire, or Bunsen burner, stirring -well during the operation, so as to mix them thoroughly; when all are -melted, add five ounces of ordinary letterpress printing-ink, and -thoroughly mix; then allow to boil and continue the heat until the gas -escaping from the bursting bubbles explodes upon the application of a -lighted taper; then remove all from the fire, and allow to cool. - -For a hard ink, for use after the plate is etched deep enough, and the -resist is cleaned off, mix - - Beeswax 1/2 ounce. - Resin 1 ounce. - Shoemaker’s Wax 1 ounce. - Black Litho Ink (about $1 a pound) 2 ounces. |56| - -Melt, then cool and mix with turpentine to make it the consistency of -soft soap. - -Now, with these and a solution of gum Arabic (in cold water), the -thickness of cream, add one-quarter pint of a decoction of nutgalls to -each quart of gum solution. The decoction of nutgalls is made by adding -one-quarter pound of bruised nutgalls to one and one-half pints of -water, in an earthenware vessel (not metal); boil, then allow to stand -at the fire and simmer gently for six hours, keeping the vessel covered -over; then allow to cool, filter and add the proper quantity to the -above gum solution. - -We will assume that a suitable place is provided for carrying on the -operations to be described, in the shape of plenty of bench room, and a -good light to work by. - -The first stage in etching a zinc plate in relief is, to slightly warm -it upon the hot plate, then allow it to cool (by-the-bye, it will be -very convenient to have a clean litho stone handy for placing the plate -upon to cool quickly). The plate being cold, with a piece of soft -sponge carefully smear it over with the gum solution, allow the gum to -dry, spontaneously, in a cold current of air; if heat be applied the -gum will crack and bring away the image from the plate. - -Whilst the gum is drying, with a palette knife place equal parts of -transfer ink (page 44) and of etching ink (page 54) upon one corner of -the inking slab, then thin to the consistency of cream, with middle -varnish, thoroughly incorporating the three ingredients with the -palette knife. - -Now place a little of this ink upon the leather roller and roll -vigorously upon the slab, so as to distribute the ink thoroughly upon -both roller and slab; be careful not to get too much ink on the roller, -nor to have it too thin; in fact, work the ink as stiff as is possible. - -Now lay the zinc upon a piece of clean paper, and sponge it gently over -with a wet sponge, so as to loosen the film of gum, then squeeze the -sponge nearly dry, and pass it over the plate again, so as to insure it -being evenly damp all over, but be careful not to make it too dry. - -Now proceed to roll up, by passing the charged roller to and fro over -the plate, using moderate pressure and slow motion, recharging the -roller at short intervals from the inking slab. Occasionally use the -damp sponge so as to keep the plate sufficiently damp to resist the ink. - -If the roller slides instead of rolling, wipe it with an old linen rag, -which will remove the moisture; then recharge the roller again upon the -slab. |57| - -The rolling is continued until the whole image is an intense black, -when it is carefully dusted over with very finely powdered resin -applied with a broad camel’s-hair brush, taking care that all the image -gets covered. Then rub it gently with a wet, soft sponge and place it -in the etching box containing a mixture of water and nitric acid, the -acid being only just perceptible to the taste. - -The plate should remain in this for one minute (the box being kept -rocking); it is then removed, and thoroughly washed back and front -under the tap. Rub it gently with a clean soft sponge. - -This etching is merely to remove any traces of gum or dirt from the -zinc which would interfere with the shellac varnish holding. - -Now dry the plates, using gentle heat, then coat the back with thin -shellac varnish to protect it from the acid; do the same to the margin -of the picture on front, also varnish the centre of any very broad -whites up to half an inch of the image, so that the acid dissolves no -more zinc than is necessary. Now examine the image carefully, and if -any of the lines are defective touch them up, and make any alterations -and additions required. - -The plate is now ready for the first etching, for which purpose a -little nitric acid is added to the water in the etching tray—precise -directions cannot be given as to how much acid to add, as so much -depends upon the area of zinc on the plate that requires dissolving; -practice, however, will soon enable the operator to judge the proper -quantity. If too much acid is added, the plate will quickly be covered -with myriads of minute bubbles, in which case it must be instantly -removed, well washed, and the bath diluted with water before the plate -is reimmersed. If, on the other hand, there is too little acid present, -the action is too slow, and more must be added. - -The first etching must be carefully watched, and the rocking continued, -until the application of the finger-nail to the margin shows that the -zinc inside has been dissolved away to a depth of about the thickness -of a visiting card. - -The first etching is the most important of the whole, as unless a -sufficient depth be attained the sharp lines will not be obtained; and -as the ink is not yet capable of resisting too strong acid, great care -must be taken that the work is not damaged; proceed cautiously, adding -acid from time to time as required. - -As a rule, the first etching will take from five to ten minutes (the -tray being kept rocking all the time). - -When it is judged that the first etching has been carried far enough, -remove the plate from the tray, wash it well under the tap, rubbing -gently with a |58| sponge, so as to remove the scum left by the acid, -dry by means of gentle heat, then allow it to cool. - -When the plate is quite cold, smear it over with gum solution, and with -a piece of cardboard, fan the gum dry. - -Now sprinkle the inking slab with turpentine, and with a cloth wipe -the slab clean. Take a piece of etching ink and thin it with middle -varnish, mixing them well with the palette knife upon the slab; now -take the leather roller, and with the palette knife place a little of -the ink upon it, and roll up on the slab until both roller and slab are -well coated; but on no account must there be too much ink, nor must it -be too thin. - -Now lay the zinc down on the bench, on a piece of clean paper, and with -the wet sponge carefully wash off the gum; then wipe all superfluous -water off the plate, and roll up with the leather roller charged as -above; roll the plate first one way, and then the other, keeping the -zinc evenly damp all over, else the ink will catch in the whites, and -probably spoil the picture. When the rolling is completed, and as much -ink as possible has been piled on, the zinc will be nearly dry. If not, -allow it to stand in a cold current for a little time, then take it to -the drawer in which the powdered resin is kept, and smear the plate -all over with the powder. Now brush as much of the resin away as will -come, using the brush from all sides, so that all the lines get evenly -coated, not only on the top, but upon the sides; this being done, take -a damp sponge and carefully remove the superfluous resin from the -whites, or unprotected zinc. - -The plate is now ready for the second etching, and the solution in -the etching tray must be reinforced by the addition of a little acid; -but do not add too much at once. It will be far best to add a little -at a time, and then, as soon as the zinc shows there is no action -going on, add a little more; an easy and simple method of ascertaining -whether any acid be present or not is to wipe the bare metal with the -tip of the finger, and if that spot (which will be brighter than the -surrounding parts) does not speedily resume its dingy color, the acid -is exhausted. - -The plate being immersed in the solution, set the tray rocking, and pay -attention to the remarks above. At the end of ten minutes remove the -plate from the tray, wash it under the tap, rub it gently with soft -sponge, then remove as much of the water as possible, and examine the -progress made by the acid. This can be seen by the lines being bare -below the ink, in which case the etching has been carried far enough, -and if not stopped, there would be danger |59| of under-cutting; if, -however, no progress has been made, add a little more acid to the -solution, replace the zinc, and rock again for another five or ten -minutes. - -The second etching being effected, the zinc is carefully washed, and -the scum left by the acid is carefully sponged away; now stand the zinc -up near the hot plate, so that it will get the benefit of a gentle -heat, and when quite dry lay it upon the hot plate (which should be -heated to a temperature of 120° to 150° F.) face up, with a piece of -brown paper between the zinc plate and the hot plate. - -As soon as the zinc plate begins to get hot, there will be a tendency -to curl slightly away from the hot plate, which, if allowed, would -prevent the ink being evenly melted. To prevent this, take a brad-awl -in each hand, and press down the sides of the zinc, taking care not to -touch any of the picture. - -Allow the zinc to remain on the hot plate until the ink and resin are -melted and run down to the bottom of the etching, then remove it and -lay it on the cold slab until the plate is cold. - -When cold, smear the plate with the gum solution, fan it dry (_never -use heat for drying the gum_), moisten with wet sponge, roll up again -(use the leather roller), using the ink pretty stiff on the inking -slab; keep the surface of the zinc well moistened. When the roller gets -too much water upon it, pass a piece of damp cheese-cloth over it to -remove the water; then roll the roller vigorously on the slab until it -again bites the ink. Continue rolling the zinc until all portions have -received due attention from the roller. N. B.—Some of the closest work -will be quite blocked up this time, and each subsequent rolling will -block up more and more, until only the very open work will be left. - -Now allow the zinc to get dry, then cover it with resin, brushing from -all sides, so as to coat the sides of the lines as well as the top, and -then remove all superfluous resin from the whites with a damp sponge. -The zinc is now ready for the next etching, for which more acid is -added to the solution in the etching tray. - -Rock the tray carefully, watching the zinc to see that the acid is -neither too weak nor too strong, until the progress can be seen by -examining the plate; the time, with the proper quantity of acid, is -twenty to thirty minutes. - -When the etching has proceeded far enough, after washing and sponging, -again allow it to dry, then place it upon the hot plate until the ink -is melted and runs down the sides of the lines; then cool, smear with -gum, fan dry, moisten with sponge, and roll up as before; dry, cover -with resin, using a |60| camel’s-hair brush, then dampen with a sponge -and give a fourth etching, using the same precautions as to strength of -acid and duration of rocking as before. - -Now cool the plate; get a little more ink on the roller, and roll the -plate whilst cold. When the surface of the lines has a nice even coat -of ink upon each and all (coarse and fine), again warm the zinc on the -hot plate until it is just too hot to hold in the fingers; then cool -it again, varnish the back with shellac varnish, then make a mark with -a blunt point, in the ink on the margin, so as to lay a short line of -zinc bare to the action of the acid. - -The round of operations is repeated; but for rolling up for the fifth -and subsequent etching, a flannel roller is used, and more ink will be -required upon the slab; it will also require to be a little thinner. - -For some subjects six or seven etchings will be required, whilst for -others—especially where there are whites that are too small for cutting -out with a fret saw or router—ten or twelve etches will be required. -Practice, the best teacher, will soon enable the operator to judge how -many are required. - -The etching having been carried as deep as is judged sufficient, -sprinkle the plate liberally with turpentine, and with a stiff -scrubbing brush loosen the ink from the lines, and wash it off with a -solution of American potash. - -The plate being cleared from all ink, etc., is now examined carefully. -The sides of the lines will show each etching, by a series of irregular -steps. If the plate be put into the press in this condition, the -chances are that before many copies had been made, these steps would -take more or less ink from the rollers, and blur the image; therefore, -before passing it into the hands of the printer, the plate will require -etching two or three times more, to get rid of these irregularities. - -This is done by warming the zinc on the hot plate, and then, whilst -still warm, rolling up with a fine glazed roller charged with the hard -etching ink from a clean inking slab. - -Roll the zinc firmly, first one way and then the other, so that all -the tops of the lines get well coated with ink; now make a mark on the -margin with a blunt point in the ink, so as to lay a short line of zinc -bare to the action of the acid. - -Next empty the etching tray, put into it some clean water, and add -sufficient acid to make it taste like strong vinegar; in this immerse -the plate, and keep rocking for ten or fifteen minutes, or until the -mark on the margin, when felt with the finger-nail, shows that it has -attained a depth about the same as that obtained in the first etching. -|61| - -Now wash the plate under the tap, and wash off the ink with turpentine, -followed by a solution of American potash; again wash and dry on the -hot plate. Now examine, and if the lines are free from the steps, the -plate is finished, but if not, the operation must be repeated until the -steps are all removed. - -Be careful to cover the surface of the block thoroughly with the ink, -else the acid will spoil the picture. - -The plate is now ready either for mounting for the press, or for -electrotypes being taken from it; if the former, the deep whites -are cut away with the router or fret saw, the edges are trimmed or -bevelled, holes are drilled and counter-sunk at convenient places, for -the insertion of nails or screws to fix the zinc to the wooden block, -to make the surface type high. - -The object aimed at in the instruction in Part I. is the production -of relief blocks on zinc from an original in black and white, which -original may be a drawing made purposely for reproduction, or it may -be from a drawing already in existence, a woodcut, or engraving, -the picture being rendered entirely in line, or a chalk drawing may -be used. In fact, any subject that is capable of being worked from -either at a type press or by ordinary (monochrome) lithography. Washed -drawings, or oil or water color drawings are not applicable. - -In fixing plans, or drawings on the easel, prior to photographing them, -if they are cockled, and difficult to get flat, pins may be placed -anywhere, so long as the lines are not interfered with, for these pins -may be painted out with a camel’s-hair brush and gamboge or Indian ink. -It is important that the plans or drawings be as flat as possible, as -if the lines are cockled, they will not be photographed straight. - -In photographing drawings on tracing paper or cloth, a piece of white -paper should be placed behind them. - -When, from an original of black lines on a white ground, it is desired -to make a reverse block—_i. e._, white lines on a black ground—a -negative is first made from the original, and from that negative -a transparency is made; and a print made upon the zinc from that -transparency will be a reverse of the original. - -Thus far I have tried to make plain the details of a process which is -as fascinating and as pretty as any in photography, and which supplies -results which could not be attained by the most expert workers two -years ago. And since those experts first obtained even tolerable -results by zinc etching, like |62| everything else in photography, -it has made wonderful progress. At first we were delighted and -content when a block was obtained with relief sufficient to enable -us to print it upon an ordinary press with type. But now we can -get from the zinc surface all the qualities which are given by the -lithographic stone. Indeed, the process of zincography bears a very -strong general resemblance to that of lithography; of course, it -varies therefrom in matters of process detail. The manipulations of -zincography, however, are no more complicated in their nature than the -details of printing, etc., from stone. Crayon drawings, ink work in -line and stipple, rubber work, in fact, anything that can be drawn on -stone can be drawn on properly prepared zinc, with the exception of -engraved lines (intaglio), the structure of the zinc not giving the -yielding brittleness of stone. The great departure made possible by -zinc plates exists in the fact that they can be bent to the surface of -a cylinder, thus displacing the reciprocating bed and stop-cylinder -of the lithographic press with the continuously rotating plate and -impression cylinder of the zincographic press, which, at the same -driving speed, produces double the number of impressions printed on -the lithographic press. To Mr. Bernard Huber, of the Huber Printing -Press Company of Taunton, Mass., belongs the credit of designing the -only American zincographic press in existence, and which is now in -successful operation in several lithographic establishments. It is a -thoroughly American machine in design and construction, and while no -glowing prophecies of its immediately taking the place of lithographic -presses are indulged in, yet this kind of press has its place and use, -and will by its qualities win favor in the trade. - -Many lithographers are beginning to give correct attention to -zincography, but few are willing to give the time and constant -experimenting to the subject that has been given by Messrs. Harris & -Jones, who during the past three years have operated the zincographic -presses in their lithographic establishment known as the Providence -Lithograph Co. Having taken the selling agency of the Huber -zincographic press, they offer to those who _buy_ the press full -instructions in zincographic surface printing. - -These suggestions are given right here, first because we are now about -to take a step higher in zinc etching—a step which will lead us to -results which lithography can scarcely equal in some particulars—and -second, because it is the policy of this work to withhold no -information which the novice will need in supplying himself with a -perfect outfit for doing the best of work. For the same reason the -advertisers have been chosen, rather than received in the usual way. - - - - -|63| - -PART II. - -PHOTO-ENGRAVING IN HALF-TONE. - - -CHAPTER I. - -RETROSPECTIVE. - -The former chapters have treated entirely upon the production of blocks -in line—_i. e._, where the picture has been made by a draughtsman, -the half-tones and gradations being communicated by a greater or less -thickness of line, or by dots, or stipple, or hatching. - -The picture for such blocks may have been specially drawn for the -process, the same size or larger, or it may be a copy of some woodcut -or engraving already in existence, but if it is desired to reproduce -blocks from drawings, paintings, or photographs, then an entirely -different method must be adopted, and the smooth gradations of -half-tone levelled, so to speak, so as to bring the high lights and the -shadows upon one plane. - -In photographs from nature (or from washed drawings or paintings) the -scale of gradations runs, as it were, in a series of short steps from -the deepest shadow to the highest light, and a block made, say in -bichromated gelatine, from such a negative can give no half-tones, as -the inking roller could only touch the deep shadows properly. - -Now the subject of making photographs applicable for the illustration -of letter-press, instead of woodcuts, has occupied the attention of -experimentalists from the early days of the art-science, as the records -of the Patent Office show. - -The first patent, dated 1852, bears the honored name of Mr. Fox Talbot, -and although it is for intaglio printing, and therefore a little out of -place under the above heading, still it claims our attention as giving -a method for breaking up the half-tones of the photograph, by placing -muslin, crape, etc., between the photographic cliche and the sensitive -surface; or a glass plate may be covered with fine lines, or glass may -be coated with powder, which is caused to adhere. |64| - -In 1854, Paul Pretsch broke up the half-tone by the reticulation of -gelatine, caused by the admixture with iodide of silver and bichromate -of potash; this was spread upon a silvered copper plate, dried, and -exposed to light under the half-tone negative, then washed in cold -water and borax, or carbonate of soda, then in alcohol, coated with -copal varnish, and immersed in a weak solution of tannin, after which -an electrotype could be made, or a transfer made to zinc or stone. - -In 1855, A. J. Berchtold produced a grain by printing upon a photograph -in black or in any color, from a plate or block or other surface, or -by perforating or making strokes, lines, or dots upon it, by roller or -other instrument. Repatented in 1883, by Brown, Barnes, and Bell. - -In 1860, E. J. Asser used starch, and in 1865, J. W. Swan used a tissue -of gelatine mixed with charcoal or other chemically inert grit; in -the same year Messrs. E. & J. Bullock published, perhaps, the most -important specification, describing all, or nearly all, practical -methods of obtaining grain, the most important of which are the -placing of any fine fabric between the lens and the sensitive surface, -or between the camera and the object, or copies of granulated or -recticulated structures or fabrics could be used, or such copy could be -placed in contact with negatives, and both copied together. - -In 1879, J. W. Swan made negatives by moving, during exposure, the -Bullock’s screen, placed in front of a sensitive plate. Meisenbach’s -method, patented a little later, is somewhat similar. - -If a Woodbury relief is thinly coated with transfer ink, and then laid -upon a piece of ordinary litho transfer paper which has been embossed -with lines, or dots, or stipple, by being pressed in contact with wire -gauze or an engraved plate, and the inked relief and the embossed litho -transfer are then subjected to heavy pressure, a grained image is -impressed upon the transfer paper, which can be transferred to zinc, -and then etched in relief. - -The method of making a grained negative to be now described, shortly -stated, is done by interposing a screen, either before the sensitive -plate in the dark slide of the camera (when copying a photograph) or -placing the screen behind a transparency on glass when transmitted -light is used. In the first instance the image projected upon the -sensitive plate, having first to pass through the screen, is broken -up by the dots upon the screen, the result being a definite grained -negative. In the second instance, the screen being placed in contact -with the transparency, a similar result follows. The first method -is most generally used, as the print does not require the careful -focussing necessitated by the second. - - -|65| - -CHAPTER II. - -MAKING GRAINED NEGATIVES. - - -THE SCREEN. - -For making grained negatives, the apparatus, chemicals, and -manipulations described in Chapters I. and II., Part I., for line -negatives, are required, with perhaps a little increased care to secure -clean and bright negatives. - -The first requirement will be a proof, on fine white paper, from a -machine-ruled plate, or a plate with fine dots or stipple; a favorite -being plates ruled diagonally and straight, either in single lines or -crossed. These plates must be of good size, say 18 by 15, ruled with -lines as fine as possible, 100 or 150 to the inch. The ruled sheet must -be perfect, as any defect in it will be fatal. - -Such a proof being secured, it should be carefully mounted with starch -paste upon a stout piece of smooth cardboard, and should be carefully -shielded from all chances of being soiled, as the slightest stain -or mark upon it will unfit it for use. As such a fine line is very -difficult to focus, especially in making the smaller screens, it will -be found a good plan to cut four narrow strips of good, bold type, and -paste these at the four corners of the sheet, just outside the ruling; -these slips of type will be easy to focus, and will render the task of -making the screens easier. - -Plates ruled with single lines, either diagonally or horizontally, may -be used instead of the cross ruling, and are by many preferred. - -Those in possession of a ruling machine may make these ruled sheets by -ruling a large litho stone, and pulling impressions from that stone. -If this is done once, and done well, the sheets will last a lifetime; -and if the stone be sufficiently large, and the lines very fine, the -screens may be used for blocks 15 by 12 inches or larger. - -To copy this ruled sheet, remove the mirror from the lens, and put the -lens in the camera in its ordinary position; then pin up the sheet -on the easel, and, after seeing that the easel and camera are quite -parallel, proceed to make a series of negatives from the sheet, making -screens of various degrees of fineness, varying from a coarse grain for -a coarse photograph, to the finest possible for |66| photographs full -of delicate half-tone, and from three inches to ten inches wide. Many -subjects will need screens made especially for them. The screens must -be free from speck or stain, and should be made upon very thin glass. - -The nitrate bath should be in good condition, and the collodion ripe. -Such negatives take a good deal of time making, but as they are the -foundation of the process, and with care will last for years, the -trouble must not be grudged. - -The screen negatives being made, they must be varnished with a good, -hard, well-filtered varnish, applied in a room quite free from dust. - -The screens must be made by the wet collodion process. The ordinary -gelatine dry-plate is utterly useless for such work. Gelatino-chloride -plates might do, but the exposure is so very long that there is risk of -shaking the camera during exposure. - - -THE GRAINED NEGATIVE. - -For the first method a good vigorous photograph is selected, placed in -position on a copying board, and the camera adjusted so as to get the -image on the focussing screen the size wanted the mirror being used, as -the negative must be reversed. - -A collodion plate is now prepared and well drained; then one of the -transparent screens is fixed in front of the carrier by drawing pins, -by passing strips of gum paper over, or by fixing with fine tacks -a piece of thin card at the top, and one at the bottom, slightly -overlapping the screen, and holding it firmly in a sort of rebate. - -The carrier is now placed in the dark slide, the sensitive plate in its -place, the door of the slide closed and fastened. - -The exposure is now made in the camera, and if the screen is properly -transparent the time will not be very much more than when copying in -the ordinary way. - -The development of the exposed plate is done by means of the developer -given in Chapter I., and the result must have all the details of the -photograph, while the lines of the screen must be clear and free from -veil. - -The negative is washed, fixed in cyanide, washed again and then -intensified, first immersing it in the solution No. 1, Chapter I., -until bleached, then thoroughly washed and blacked with No. 2 solution, -again washed, and varnished with the water varnish, or dried and -varnished with benzole varnish. - -For the second method we shall require, instead of a paper photograph, -a transparency on glass. |67| - -The transparency may be made on a gelatine dry-plate by printing in -contact with the negative, or an enlarged transparency may be made, -either on a dry plate or by the wet collodion process. - -The transparency should be made by contact, when the original negative -is of larger size than the block required; the enlarged transparency is -used if the negative be smaller or the same size as the block. - -The development of the transparencies on gelatine dry-plates will be -treated of later, but if wet collodion be used, the manipulations will -be the same as for negatives, except that the image is in reverse -gradations, the lights being clear glass, and the shades dense and -black. Every detail in lights, shadows, and half-tones must show -distinct and strong. - -[Illustration: Fig. 5.] - -For the production of these enlarged transparencies, an enlarging -camera will be required, which may be provided by having an arrangement -in front of the ordinary camera, fitted like the accompanying figure, -consisting of two boxes, one sliding within the other, the negative -from which the transparency is to be made being placed in a carrier at -B. - -In the illustration the sides are shown open, but only for simplicity, -as they must be quite opaque. In using such an arrangement, the camera -must be brought under the skylight of the studio, and the light -reflected through the negative, by placing a large sheet of white paper -at an angle of forty-five degrees in front of the negative. - -Another and perhaps better method will be to cut a hole in a dark-room -at a proper height for the camera, and fix the negative in the hole, -then adjust the focus upon the screen, illuminating the negative by -means of a reflector fixed at an angle of forty-five degrees. - -The transparency being secured, it is varnished, and all blemishes or -spots removed by means of a sable brush, and a little carmine color; it -is then placed in contact with a suitable screen, and the two together -are inserted in the |68| place previously occupied by the original -negative. Now adjust the camera so as to get the image on the focussing -screen the proper size, and proceed to make a grained negative by the -wet collodion process exactly as described in Chapter II., Part I., -and above. When a negative containing all the details of the original -negative broken up by the fine grain of the screen is obtained, it may -be dried and varnished, and then it is ready for printing upon the zinc. - -All pinholes, etc., should be stopped by means of a fine sable brush -and Indian ink. The printing on the zinc should be done by the bitumen -process, Chapter VI., Part I., as the albumen is not nearly so perfect. -If, however, the albumen process be preferred, the printing is done in -the same way as described in Chapter V., but extra care must be taken, -first, that the zinc plate is thoroughly and evenly polished; secondly, -that the graining bath is kept weak with plenty of alum in, so as to -have the grain on the plate as fine as possible; thirdly, that no -speck of dust, dirt, or any air-bubbles be on the film after coating, -and that the whirling be effectually done so as to get the sensitive -coating as even as possible. - -The inking up requires no comment, as it must be done as evenly and -thinly as possible, for both line and half-tone. - -In development, a little more energetic friction will be necessary, but -extreme care must be taken not to abrade the ink surface. Continue the -rubbing until all the details are developed, and bear in mind that the -finished block will be exactly like the zinc after development. - -In printing these half-tone zincs, it often happens (like printing -in silver) that to get the best results some portions will require -less exposure than others. The best way to stop back any portion or -portions, is to cover the front glass of the printing frame with -whiting mixed with water to the consistency of thick cream; apply with -a rag over the places in the negative, before exposing to light, and -at the end of one-third, or in case of very deep shades, one-half the -exposure, clean off the whiting and finish the exposure without any -obstruction to the light. - -The exposure to a grained half-tone negative will be one-half to double -as long as a simple line negative. - -A perfect print on the zinc must contain all the grain intact, for -if there is any break in its continuity, it is of no use to proceed -further with it. - -The printing in bitumen requires no more comment than to say care is -necessary to avoid dust. The smallest speck will be likely to spoil an -otherwise perfect print. - - -|69| - -CHAPTER III. - -ETCHING IN HALF-TONE. - - -WHEN THE PRINT IS IN ALBUMEN. - -The zinc plate with the image upon it in ink, is dried, then warmed -slightly on the hot plate, cooled, and coated with thick gum* and -fanned dry (not dried by heat, or the gum is certain to crack and bring -away the image or part of it); then wash it under the tap, and rub it -gently with a fine sponge so as to remove all gum from the ink, but -not from the zinc. Next proceed to roll up as directed in Chapter V., -using the India-rubber roller charged with stiff ink. The surface of -the zinc should be kept well covered with water. Use as little pressure -as possible, but let the motion be fairly rapid, and if any portions of -the image should smear, roll rapidly with slightly increased pressure. - - * See page 55, Part I., Gum and Nut-galls. - -This operation of rolling up the image is the crucial one, for unless -it is done properly, when it is finished, the result is a strong black -and perfectly even image; it is of no use proceeding further with it, -for in fact the picture must be perfect. - -The rolling up being done, any touching up that may be required can -now be done, and any fine details clouded over, or made indistinct by -the grain, strengthened or opened out. Additions should be made with -transfer ink thinned with turpentine, laid on with a very fine sable -brush. The whites are put in by scratching through the ink with a fine -etching needle. - -To rest the hand upon in doing this touching up, so as to avoid -touching the image, a bridge is used made of a strip of smooth wood, -one inch wide, quarter of an inch thick, and sufficiently long to well -span the plate; at each end of this strip nail narrow strips a quarter -of an inch thick to serve as the feet for the bridge to stand upon. -Then the zinc may be slid under it without touching the surface against -the under part of the bridge. - -The zinc is now ready for the first etching in the rocking tray. -The nitric acid solution must be very weak indeed to the taste, the -presence of acid being just perceptible. The time of immersion in the -first bath must not be longer |70| than thirty seconds; then the zinc -is removed, washed under the tap, and gently rubbed with a sponge; dry -it gently on the hot plate, allow the zinc to cool, coat it with gum, -fan it dry, rinse it under the tap and rub it with a sponge; then again -roll up, when it is ready for the second etching; that is done in the -same bath as the first, without any addition of acid. Keep the tray -gently rocking for three minutes, then again withdraw, wash it under -the tap, rubbing with sponge, coat with gum, fan dry, wash under the -tap rubbing gently with sponge, and again roll up, using the ink on -the roller a little thicker, but stiff. When the image has taken the -ink equally, place it on the hot plate and allow the zinc to get hot -enough to melt the ink slightly; then allow it to cool, and place it in -the etching bath, slightly reinforced with a few drops of nitric acid. -Immerse it this time for five minutes. - -The operations of washing, gumming, rolling up, etc., are to be -repeated until it is judged that the etching has been carried far -enough. The time of immersion in the acid solution with each etching -may be lengthened, but take special care to keep the bath weak until -near the last etching, when the strength may be slightly increased. - -The resist is cleaned off with turpentine and a stiff brush, and then a -proof is pulled. If further etching will improve it wholly or in part, -the plate is inked up and again subjected to the action of the acid -bath. - -If only portions require reëtching, cover the rest with bitumen -varnish; but it will be scarcely safe to give more than one etching -after cleaning off the original resist. - - -WHEN THE IMAGE IS IN BITUMEN. - -A bitumen image is etched in the first bath in which the acid is -just perceptible to the taste, without any preliminary rolling up. -The duration of the first etching may be prolonged for three or five -minutes; then the plate is withdrawn and well washed. Remove any scum -with a soft sponge; then dry it in a cold current, and smear it with -gum, fan it dry, and roll up with a leather roller charged with stiff -ink, until all portions of the image have taken a film of ink. Now -reinforce the nitrate bath with a few drops of nitric acid, and again -immerse the plate, rocking the bath for ten minutes; watch the picture -carefully so that in case of undercutting the plate may be removed -before any mischief is done. - -The plate is again removed, washed, rubbed with a sponge, and dried; it -is |71| then warmed on the hot plate, so as to slightly melt the ink, -then allowed to cool, smeared with gum, fanned dry, damped over with -a wet sponge, and rolled up, the roller being charged with stiff ink. -The plate is now ready for another etching, for which the bath must -be strengthened by the addition of more acid. The immersion (rocking -all the time) may be fifteen or twenty minutes, after which the plate -is withdrawn, washed, rubbed with a sponge, and if it is thought -another etching would improve it, the cycle of operations is repeated, -beginning with warming the zinc on the hot plate. - -After the resist is cleaned off (which with bitumen must be done first -with turpentine and then with benzoline) further etching may be given, -if deemed necessary, first inking up well with the hard ink mentioned -in Chapter VIII., and then reimmersing in a weak bath of acid and -water. If only a portion requires reëtching, those parts that are not -to be touched, are protected by coating with bitumen varnish. - -The plate being etched, now requires finishing. - -The outside zinc is removed with a circular saw and then the edges are -filed and holes drilled at an angle, so that the metal can be fixed -upon the block. - - -|72| - -CHAPTER IV. - -PRINTING FROM THE BLOCK. - -A half-tone block to give results commensurate with the care needed -in its preparation, must be handled by the machine man with care and -consideration. - -The blanket on the tympan or cylinder must be replaced with something -harder, else the soft pressure of the blanket will blur the print. - -The block must also be made ready, not by putting cut-outs on the -tympan or cylinder, but underneath the block, and there as thin as -possible. - -The ink must be good and not too thin; the rollers must be free from -flaws and not too tacky. In fact, as much care is required on the -press as during the photographic and subsequent operations. Indeed -photo-engraving and zinc etching would have come into popular use -more rapidly than they have, if printers had been willing to give -them the special “making-ready” attention they require. Despite all -prejudice and indifference, “process-engraving” so called, has made -continuous improvement ever since it came into use, and the good work -goes on. The most delicate gradations of light and shade discernible -in nature, may, from the photographic plate, be rendered in pure black -and white by means of any of the methods given in this work. All that -nature displays, and all that imagination compels, may be reproduced -indefinitely. - -With regard to the storage and keeping of zinc blocks after using, Mr. -T. Bolas, in the _Photographic News_ of September 24, 1886, says, “they -should not be washed with the usual lye, but should have a few drops -of paraffine oil poured upon them; and after this has been well rubbed -in by a soft brush kept for the purpose, the paraffine should be well -wiped away with a soft cloth. If the block is to be stored away for a -long time, it should be waxed. The best way of doing this will be to -make it rather warmer than is necessary to melt wax, and then to rub it -over with a piece of yellow bees’-wax, after which the excess is wiped -off with a piece of flannel.” - -Sometimes zinc blocks are electroplated with copper or nickel (a -necessity when they are to be used for certain color work), and such -blocks should also be treated in the same way as the bare zinc, as they -cannot be safely cleaned with the lye solution. - - -|73| - -CHAPTER V. - -THE TRANSFER OF THE DRAWING, AND ITS TREATMENT BEFORE ETCHING. - -According to the methods of producing them, classify the drawings as -follows: - -(_a_) Freehand drawings in crayon or ink, drawn with lithographical -chalk on rough paper, or with pen and chemical Indian ink on paper -prepared for transferring. - -(_b_) Lithographical transfer of engravings, pen-and-ink crayon -drawings, or drawings on stone. - -(_c_) Transfers from relief plates made in copper, steel, zinc, or lead -(music). - -(_d_) Anastatic transfers. - -(_e_) Fat or resin prints from photographic negatives. - -Proceed as follows: - -(_a_) _Transfer of hand-drawing._—Place the drawing to be transferred -with its face upon a sheet of clean, white paper, and moisten the -back with a weak solution of nitric acid (1/2° Baumé), by means of a -sponge. Over-moistening causes obliteration of the drawing, fringing -of the single lines, and the running together of the hatched portions. -The correct degree of moisture can be ascertained when the side -prepared and drawn upon grows slightly sticky, and when the drawing -becomes glossy. This will take place in from four to five minutes -after moistening. This time is to be spent in arranging the zinc in -the press, after having freed it from all greasiness. Place a card on -the rolling press below the drawing and the zinc; above it, a sheet -of good blotting-paper, a sheet of Bristol paper and are of pressing -board; then make a trial print with the press, a clean piece of paper -taking the place of the drawing. The correct pressure is a matter of -experience; it is advisable to begin with a pressure less by one sheet, -in order to be able to increase it during the process of transfer. - -In the lithographic press the ink-block is first to be adjusted; since -it needs a greater “setting in” than the rolling press, the zinc must -be cut larger. It must extend three centimetres on all sides beyond -the drawing. The edges of the cut plate must be well ground off, in -order that the ink-block may not be |74| caught; at all events, it is -advisable to have the latter smaller than the plate. Observe that the -range of the press should be regulated; then place the zinc directly, -without any intervening layer of paper, on a solid stone; lay upon it -a clean sheet of paper, a blotter, a sheet of Bristol paper, and a -pressing board well covered with tallow. Make a trial by drawing the -sheet through at a moderate pressure. If all is arranged, the work of -transfer can be started. The temperature of the zinc should now be -about 35° C. - -Place the drawing down carefully, without moving it about; upon it the -blotter, the Bristol paper, and a pressing board, and draw it through -three times with constantly increasing pressure; turn the plate in -a contrary direction, and draw it through three times in the same -manner. Now place a moistened sheet of good paper between the blotter -and the drawing, and draw through, first with weak, and then with -strong pressure, three times in both positions. Instead of turning the -zinc, the ink-block may be reversed. This finishes the operation of -transprinting, and the next question is the loosening of the paper from -the zinc. Here we can pursue two methods: first, we can have hot water -and a porcelain tray at hand; place the copied plate in the tray, and -pour the water upon it. The coated layer bearing the drawing begins to -separate from the paper. Shaking the tray promotes this action, and -soon the paper will loosen itself from the layer which remains attached -to the zinc. With the second method proceed thus: moisten the back of -the copied drawing, thoroughly with a sponge and cold water; allow it -to soak in, warm the plate to 60°–65° C. and carefully rub all parts by -hand. The layer will again separate by degrees from the paper, which -latter we can then easily lift off from the plate. - -On account of the strongly gelatinous layer, crayons on grained paper -should only be moistened moderately before and after the first rolling, -in order to avoid the coiling of the paper. - -Hand-drawings on paper without coloring require treatment with stronger -acid (I recommend nitric acid, 4° Beaumé). At the same time the drawing -should be cut as close as possible. To draw it through securely, place -it as usual upon the zinc, and above it a piece of prepared copy paper -moderately moistened, and a trifle larger than the drawing, then a -blotter, a Bristol board, and a thick card, and draw through as before. -The coated copy paper sticks tight to the zinc after the first rolling; -it also retains the drawing in its first position, and allows repeated -rolling. If the original was over-moist when |75| copying, it sticks -to the zinc and separates with difficulty; if the moistening was just -right, two perfect copies can often be made from the same original. - -I have attempted to copy drawings on a fatty zinc surface, and to etch -them strongly, but, far from being satisfied with the result, I prefer -the above method. - -(_b_ and _c_) Copies of lithographs, type, plates for printing of any -kind, plates for _deep_ printing, I make on well satinized copying -paper*; in making the prints, I employ a copying ink as thick as -possible, with the addition of a few drops of a thick solution of -asphaltum in lavender oil, rolling a long time with but little color, -so as to get a sharp rather than a heavy print. - - * Instead of the paste-gelatine-chalk, I prefer to prepare - the surface with a decoction of semina psyllii. - -Plates for _deep_ printing, I heat equally throughout before applying -the color. Instead of color, I rub them with chemical Indian ink, wipe -the surface carefully, even polish it finally with a ball and some -Frankfort black. I then draw it through and again heat it uniformly, so -that the copy comes off of itself. Fine, sharp transfers, with perfect -relief, are thus obtained. - -(_d_) Anastatic copies are no longer of great value, since they always -turn out roughly and cannot compare with photographic copies. Although -I possess a safe method, I believe that I will have to omit it on -account of the limited space of my work and the minute importance of -the results. - -(_e_) Photographic fat or resin prints should be treated like ordinary -prints. Moisten them on the back with water—which is preferable to -placing them between moistened blotting-paper, since the drawing does -not grow too wet—and wait till they are easily flexible. Drops of water -on the film can and often do destroy the proof. Draw the plate through -with increasing pressure and one intermediate moistening. Prints in -fatty inks necessitate a temperature of plate of 35° C. Prints with -dissolved etching varnish (resin) as a printing film should have from -50°–60° C. When loosening the paper avoid warming, but moisten well. -Sticking of the gelatine film happens, especially with Husnik’s paper; -a safe remedy is to dry the copy in strong light, after developing. -Old sensitized paper, on the contrary, seldom sticks at all, and fresh -paper should always be sought. - -In printing with the rolling press, I observe that the rollers of the -press need only once to be regulated, and that greater or less pressure -can be attained by thicker or thinner covering of the print with -sheets of paper. This gives much greater security than can be had when -constantly readjusting the rollers. |76| - - -THE FURTHER TREATMENT OF THE TRANSFER. - -Should we now proceed directly to etch the copy, the acid would act -through the drawing, which is as yet but loosely attached to the zinc, -and would at last cause the lines to appear broken, if not destroy them. - -It is, therefore, necessary to replace the loose copy by a possibly -dense etching varnish, attached fast to the zinc, and to produce an -intimate connection between the latter and the etching varnish. Here we -meet a difference between the French and Austrian methods. The former, -totally based on the lithographic process, favors the use of a resinous -dense color as a _strengthening material_, whereas the Austrian method -employs an ordinary copying color and endeavors to form an etching -varnish by sprinkling and melting in a quantity of finely pulverized -resin. In the method of etching with copper sulphate, it was attempted -to restrict the corroding action of the sulphuric acid by the following -method: The drawing, rubbed with color and thinly besprinkled with -resin, was slightly melted in, then sprinkled and rubbed with the -finest silver graphite or real water-gold. It was thus made an electric -conductor. A thin coating of copper was then deposited on the drawing, -which, in point of fact, hindered the destruction of the film. At the -same time, however, the process became uncontrollable, since often a -deposit of amorphous copper became tightly fastened to the metallic -surface. The lateral action could not well be ascertained, since the -narrowest parts were often clogged with metal, without preventing -corrosion from below. - -The French method of etching is this: A thick solution of gum-arabic -is mixed with extract of nutgalls; this is carefully spread over the -surface of the plate by means of a fine sponge, and dried by a fan. -Then a knife’s point full of etching color (composed of 500 grammes -chalk color, 40 grammes coagulated mutton suet, 40 grammes soap, 125 -grammes yellow wax, 40 grammes margarin, and 40 grammes oleine, melted -in the warm bath and passed through the color mill) is dissolved in -oil of turpentine, and a portion of this solution is spread uniformly -on the grinding stone by means of a fine sponge, so that the latter -contains a similar layer of color throughout. The fatty gum film -is then washed, with a wet sponge, free from fat and acid; a fresh -quantity of the gum and nutgall solution is poured out, and the copy -is by degrees strengthened by rubbing on the etching color with a -sponge. This is repeated until the drawing has attained the proper -strength throughout. The superposed layer of gum is then washed off, -the superfluous water is removed with a sponge, a wet cloth, and -blotting-paper, dried with a fan, then gently warmed. |77| - -Now the plate is to be dusted with the finest pulverized resin, -consisting of equal parts of Syrian asphalt, washed in alcohol, and of -mastic; the superfluous resin is removed with a brush and some cotton; -the plate is then carefully heated, without beginning to melt the -resin, however. - -This, by the French method, finishes the plate for etching. Only weak -acid is safe for such a plate, however. - -According to the Austrian method (practised by me for several years), -we proceed as follows: The copied plate is first copiously coated with -a cold saturated solution of gallic acid, and then with a pure solution -of gum. Without allowing it to dry, I remove the superfluous preparing -materials with a wet sponge, and pour on some fresh gallic acid, as -with an excess of acid the drawing assumes a more brilliant black color. - -The strengthening with ordinary copying color I effect, as the case may -be, with the rollers, the sponge, or by coating. - -(_a_) _Strengthening with the Rollers._—I roll out some thick copying -ink with good, rough rollers which have been frequently used, and begin -to roll the transfer plate while still damp, without any pressure, till -its surface begins to dry. I then grasp the handles of the rollers -more firmly and blacken the dry plate uniformly, giving it a thin -coat of ink. This done, I moisten it a little and roll it regularly -with rollers freshly treated with color, so that the picture comes up -harmoniously and strongly. - -Rolling off during drying keeps the gum solution from the drawing while -drying on, and keeps open the connection for rolling in. - -Before going further I will explain the terms used*: To roll in is -to give color or ink, and is done slowly, with tightly grasped handles -and certain pressure. Rolling off is effected with loosely grasped -handles, without pressure, and quickly, and is intended to draw off -with the rollers any excess of color on the plate. _To work out_ or -_make the rollers_ means to bring fresh color on it from the grinding -stone, and is done with strong pressure and strong traction. The -correct management of the rollers rests in the wrists. To _reverse the -rollers_, to _change the handles_, means to turn the rollers around, -to make the left-hand handle the right-hand one, and thus to correct -irregularities in the distribution of color. After every advance and -return on the stone or plate to be blackened the rollers are newly -adjusted. The plate thus strengthened must be well |78| washed with -clear water, to be dried, and at times even to be retouched with a -brush and color dissolved in oil of turpentine. - - * Color and ink are synonymous. “Burn in” and “melt in” mean - the same. - -(_b_) _Blackening in_ with a sponge. The initiatory etching is done -with gallic acid, the gum coating put on and additional gallic -acid poured over; then some turpentine solution of copy color, the -consistency of syrup, is rubbed over the plate until the picture is -uniformly strengthened. If, as may happen in hand-drawings, the color -should become massed and not attach itself smoothly, it must be washed -off with turpentine and then clean color must be rubbed on. - -This operation requires great delicacy. After having finished the -blackening in, rinse well, dry with a sponge and thick blotting paper. -Heat, so as to vaporize the last remnants of dampness, and retouch. - -(_c_) A peculiar method of strengthening, nowhere described, as far as -I know, is that of drying the plate after coating it with gum, then -washing the gum with water; then, after drying, of covering the plate -with a thin solution of wax, asphaltum, rosin, and shellac in ether, -and of carefully coating the quickly drying film with gum. The film -remains on the lines of the copy, but easily detaches itself from the -bright metallic spaces, which have an insoluble combination with the -gallic acid and gum, and are thus protected from the fat. - -_Faults in strengthening_ are caused by the following: - -_a._ By ink which is too thick or too thin, or which has not been well -ground. Stripes are caused by the dissolving of the color which is -already present. - -_b._ By excessive dampness on the plate (it does not take the color; -the color in the sponge changes to a slimy emulsion). - -_c._ By too great pressure with the color sponge the fine parts are -lost. The same is the case with careless washing of the color of -hand-drawings. - -_d._ In _rolling on_ excessive moisture on the plate spoils the work. -The surface of the rollers becomes glossy and must be again inked. - -_e._ In pouring out the ink a very thick layer prevents the -strengthening of the finest lines. - -Dirt on the plate often comes from handling the drawings; it must be -scratched off and the plate must be perfect before proceeding. - -Now comes the changing of the ink into an etching varnish. But before -beginning we must cover the free edges of the zinc for the distance -of half a centimetre around the drawing with a solution of ink in -turpentine; the same applies to large white surfaces in the drawing, -which it is more convenient to cut out with a scroll saw. Then subject -the plate to the finest asphaltum |79| powder, passed through a -hair-sieve, and cover it by the dusting brush copiously with powdered -rosin. Continue the rubbing on of fresh powder for a minute, until the -ink is saturated, then dust out the superfluous powder with the dusting -brush and fine cotton, so that the metal is bright (no film should be -perceptible on looking over it). - -The plate should now be heated to about 60° C., till the color of the -asphaltum changes from a coffee tint to a dead (matt) black. Place the -plate in this condition a second time with the asphaltum, which is -again absorbed rapidly. Dust off carefully as before and burn in again -till the color changes to a somewhat shiny black; the yellow tint must -be avoided, because this degree of burning exposes the lights in the -closest hatchings to the danger of running together. - -Thus the coat of color is changed into an etching varnish of excellent -resistance and adhesion, and the plate is ready for etching. - - -THE ETCHING AND ITS INTERMEDIATE TREATMENT BEFORE MOUNTING THE CLICHÉ. - -_Introductory remarks._—If we examine a wood cut or an electrotype with -regard to the depth of its narrow and wide-line complexes, we can at -once determine a plane for the closest hatchings; in a uniformly deep -layer the lines lie at a moderate distance apart, and those of the -highest lights are very deep. These three planes are situated higher -or lower according to the very narrow or very wide series of lines. -This gives a natural division of the different stages of etching, and, -according to the three depths, we distinguish the _sharp etching_ or -_etching on_ in which the engraving must advance far enough to place -the narrowest portions sufficiently low; _middle etching_, which has -to accomplish the same for the moderately narrow portions, and _deep -etching_, which must attain sufficient depth for the highest lights. - -On account of the lateral action of the acid it is impossible to etch -down perpendicularly, but a wider covering is taken for each stage. Of -these wider coverings there remain after etching all around the relief -two terrace like grades, which must also be removed. - -We have, then, in addition to the above, three sorts of etching, a -_round etching_, in which the grade remaining from the deep etching is -to be removed, and a _clean etching_, or a removal of the wire-edge -left after middle etching. - -This natural subdivision is found in the old French method as well -as in the |80| new method, and both coating and the acids are of a -strength proportionate to the different stages of the work. - -We have already alluded to the lateral action of the acid; it is a -factor that taxes the care of the etcher in the highest degree. In the -beginning of the action of the acid, the edge of the metal under the -coating is exposed the more, the longer the action lasts; here, of -course, the dissolving power becomes apparent. The deeper we go, the -more the metal under the line is exposed, and the action on the lateral -edge continually increases. In the effect of the acid we distinguish -thence, a perpendicular and a lateral action. Since the latter cannot -be removed by changing the character of the acid, we must give it a -part in this process of dissolving metals, but at the same time must -invent a method which will prevent the lines from growing thin. - -But in order to do this we must know the relation of the perpendicular -to side action. Both are in proportion, a result both of theoretical -and practical consideration. In order then to attain a certain depth of -etching, a proportional lateral protection must take place, which is -by degrees destroyed by the lateral action. Since this lateral action -sets in at the beginning of the work, the dimension of the line must -be secured from the start. This is done in the Vienna method by the -already mentioned formation of the etching varnish, by means of dusting -with resin and burning in, by which an almost imperceptible growing of -the width of line is attained. The French method endeavors to correct -this by using a very weak acid and a correspondingly thin coating, -but coating oftener and etching at every new coating, as we shall see -below. Also the coating for middle and deep etching must be arranged in -accordance with the principles above elucidated. As deep as the middle -or deep etching is desired, so wide must the lines be surrounded by -etching varnish. - - -ETCHING BY THE FRENCH METHOD. - -We have already seen (p. 76) how a copy is made by the French method -for etching, and we now continue the development of this process. - -Into a tray pour 4 litres of water at 18° C., add 15 c.cm. nitric -acid and mix well by shaking. Then place the prepared plate into the -bath and rock it for seven or ten minutes (according to the fineness -of the drawing), rinse well with water, remove the remaining water -with blotting paper, and, finally, dry thoroughly with a fan. (Do not -forget to dry the back.) Now warm the plate from the back, moving the -flame about continually, so as to secure uniform heating and prevent -warping of the zinc. The asphalt powder, which is as |81| yet but -loosely attached, is more intimately connected with the subjacent ink -through this heating process. The combination becomes evident from -the assumption of a black lustre. With the appearance of this, stop -heating, and lay the plate on a cold stone to cool. This done, spread -some gallic acid over it with a soft sponge, and without washing it -off, spread gum on the surface of the plate, and hasten the drying with -a fan. - -Mix some etching ink with varnish and work it out into a thin layer -with good rough rollers. If the rollers are in order, wash the coat of -gallic acid and gum from the plate, remove superfluous water and _roll -in_ (the manner similar to that used in lithography). The surface of -the plate should not be more than moderately damp, so that the rollers -may not slip. If a coat of color has been uniformly deposited, wash the -plate with clean water, remove the excess with a sponge and blotter, -dry by fan and remove all moisture by heating to 45° C. Dust the warm -plate again with asphaltum (remove the excess), and warm it a trifle -to secure better adherence. Strengthen the bath by the addition of -15 c.cm. nitric acid, and etch again for seven or ten minutes under -continued shaking. Then rinse the plate, remove the water and dry with -a fan, and burn in the resin powder well. Careful inspection will now -show a successful and uniform but still weak relief. - -As before, the plate is coated with gallic acid and solution of gum, -is dried, washed, and _blackened in_, in which treatment one-third -“wax pomatum”* is mixed with the etching ink. After washing and -drying heat the plate up to 60° C., thus causing an imperceptible -widening of the drawing. After coating dust once more with asphaltum, -warm it and cover only the back and the white rim around the drawing -with a solution of shellac (1 part ruby shellac in 10 parts spirits). -Strengthen the bath with 20 c.cm. of acid and bathe it for seven to -ten minutes, shaking the bath regularly. Continue until you see that -the lateral action of the acid has almost wholly destroyed the lateral -covering produced by heating. Do not, however, etch too long, and do -not mistake the _over_-hanging coat for the other. Then follow washing, -drying, melting on some resin, cooling, coating with gum, blacking -in with equal parts of etching ink and “wax pomatum,” then washing, -drying, greater heating (70° C.) (so that by increasing the ink each -line receives lateral protection), cool and dust to excess with the -finest resin dust. |82| - - * Wax pomatum is prepared by cutting beeswax into fine - parts and covering it in a wide-necked flask with oil of - turpentine. In a few days a jelly-like mixture will remain, - which serves the above purpose. - -As we have now reached the necessary depth for the narrowest portions, -we use, instead of the asphaltum, resin, which melts easily and spreads -out readily, in order to attain protection for our middle etching. - -Strengthen the bath with 30 c.cm. acid, and bathe until the lateral -action of the acid has reduced the lateral coating to a narrow edge. -Then wash, dry, melt on some resin, cool, prepare with gum. Blacken in -as before, but employ one-third etching ink and two-thirds wax pomade -and apply so thickly that all the narrowest spaces of the drawing are -completely filled with color. Continue warming until the ink, which was -applied, has well covered each line; then dry and use resin as before. - -The acid may now be strengthened by 100–158 c.cm., according to the -strength of coating chosen. Bathing must be continued until the edge -that has run off begins to grow narrow. Wash, dry, burn in resin, cool, -coat with gum, and blacken in by rollers with clean wax. Continue -heating until each line is well covered by ink. Always dust until the -ink is fully saturated and then heat gently. - -Strengthen the bath 200 c.cm. and begin the _deep etching_. According -to the depth to be attained repeat the manipulation of strengthening -once or twice. Whenever a corrosion of the lateral coating becomes -apparent, coat freshly, adhering to the above order of operation. For -obtaining the necessary depth ink is applied about _ten_ times, adding -wax each time to facilitate the spreading when warming. - -In order to attain a fine, regular lateral coating, great ability in -manipulating the rollers is necessary, since without such the correct -degree of strengthening is never attained. Irregular coating leads, -of course, to irregular melting of the ink; one spot then is already -sufficiently wide, while another is not yet covered. In such cases -coating with a brush must be resorted to. - -If the necessary depth is attained, the plate is to be freed carefully -from the coating with a brush and oil of turpentine, and then placed in -fresh sawdust, which absorbs the oil of turpentine and leaves behind -a clean surface. Now the work can be criticised in all its parts. To -every coating is a corresponding narrow edge of etching, which is now -to be removed in order to make the plate fit for printing. To removing -these edges we must devote our attention. We begin with the top one, -and make preparations thus: Roll out on a clean, warm stone with -faultlessly smooth rollers a very thin gauze-like layer of etching ink. -Likewise warm the zinc plate and roll it in all directions without -pressure till the picture becomes beautifully black. |83| - -Pressure must not be employed, but the coating must be obtained by -renewed _working out_ of the rollers on the _color-slab_, and repeated -coating. When at last the desired strength is obtained, dust with the -finest asphaltum powder, blow the traces of dust out of the hollows, -and warm till the layer becomes slightly brilliant. Next, etch in a new -bath of 4000 c.cm. of water and 40 c.cm. of acid for 7 minutes, wash, -and dry well; then, with more ink on the rollers, coat the dried plate, -dust once with resin, heat gently, then apply the asphaltum and burn in -strongly. Thus the first relief is protected laterally, and the first -grade can be etched down completely, without endangering the drawing. -To remove the second grade, we repeat washing, and put on etching ink -mixed with one-third wax. Rolling must continue till the narrowest -spaces of the etching are completely closed. Then follow dusting with -resin, warming, and placing the warm plate in the asphalt, dusting, -removing the excess, and finally burning in. - -With this coating a further rounding of the grades can take place (in -a bath of 10° Baumé). Continue this process until all the grades are -removed and the etching appears as perfect as a cast plate. - -Since hitherto all publications on chemigraphy have duly described -this method, I believe that I should not enter into further details, -improvements, etc. Suffice it to call attention to weak points. In -view of the new method later to be described, the reader may make a -comparison between the two. - -A very weak point is the method of strengthening based on the -lithographic process of superimposing new color upon the old color. -In consequence of the repeated melting in of resin, this latter -acquires an uneven surface, which can be blackened in only with great -difficulty. Equally untrustworthy is the lateral protection by _melting -off_, which is only attained with safe uniformity by skilled workers. -And what is more, with the weak coating at the beginning; even weak -acid often works its way through to the etching, so that the finished -etching appears slightly porous, and gives no dense black print. Also -shaking, which is to promote the removal of the metallic mud and the -gas bubbles from the lines of the etching, has an unsatisfactory -effect, inasmuch as the single lines are often thus under-washed. - -But the principal defect is that no accurate determination of the -degree of each operation can be made, everything depending on the -delicate execution of the process. - -The time that the etching of a correct, deep cliché requires by this -method is from eight to ten hours. This procedure also demands better -trained hands |84| than the Austrian, which, in large establishments, -is based on a division of labor, and in which men trained in a single -manipulation, under good supervision, accomplish the maximum work -surely and excellently. - -Furthermore, the expenses of the manufacture on a large scale are -far greater, since each etcher draws a greater salary than a workman -skilled in a few manipulations, such as the following method requires. - - -THE AUSTRIAN METHOD—THE ETCHING ON. - -I have already shown how a transferred plate should be prepared for -etching by this method. Before proceeding to the details, however, -we will prepare the etching baths, which, by the way, may always be -employed for several plates. Corresponding to the three steps of -etching, we require three baths of different concentration to be -determined by means of an areometer with a Baumé scale. The bath for -_etching on_ is prepared in strength of 2° Baumé at a temperature -of 18° C. There must be a quantity sufficient to cover the plate to -a depth of 4 to 5 centimetres. The bath for middle etching requires -10° Baumé and a temperature of 18° C.; the bath for deep etching, -18° Baumé. These baths are prepared at the beginning, and are used -for the five successive stages of etching. If, after continued use, -the bath for deep etching should grow weak, it may be used for middle -etching. For protecting the trays, I recommend a coat of gutta-percha -over a well-coated inner surface of asphaltum. Everything being ready, -immerse the prepared plate in the bath, and with an etching-brush brush -the surface of the plate uniformly for two minutes. - -The hairs of the brush must only rest lightly on the metallic surface. -For determining time, use sand-glasses of two, three, and five minutes. -After two minutes, take the plate out of the acid, wash it well with -water, and examine it carefully. If the effect has not been uniform, -see that two minutes more can be safely given in the etching bath. If -by any sort of careless handling the plate has been injured, dry it -with blotting-paper, vaporize the remaining dampness, and cover the -soiled spot with very thick solution of asphaltum in turpentine. Cool, -and continue brushing lightly for two minutes in the bath. - -At the end of this time, wash and examine again. Even now everything -will be intact. With very fine drawings, however, lateral action has -already progressed so far that, under all circumstances, the exposed -edges must be covered. Coarser drawings generally stand one or two -minutes more. - -To try the depth of etching: with your finger-nail on the edge of the -black |85| rim, feel how far the etching-on has proceeded. As soon as -the finger-nail catches, the depth is sufficient, and the sides of the -lines may be covered. - -For this operation the plate needs, above all, thorough washing, drying -on both sides by blotting-paper and gentle heat, and a temperature -of 45° C. At this temperature place the plate into the finest -resin-powder, and rub the latter several times over the warm drawing, -using for this purpose a fine brush. The protection, which has grown -sticky through heating, retains a thin coating of resin, which, after -dusting off the bright metallic spots with a brush and fine cotton, -and after careful fanning off, is reheated to about 50° C. At this -temperature the plate is returned to the white rosin, receives a good -dusting-in, and being freed from excess as before, is heated to about -65°, so that the easily fusible rosin begins to spread out. At this -moment extinguish the light, and put the plate into the asphaltum, -which will attach itself copiously to the sticky resin. Brush the plate -well with the substance, remove any excess from the bright spots, heat -to 80° C.; then place it again into the asphaltum, brush it, clean -it by removing any excess, and heat it to 100° C., when a complete -combination of the resinous mass takes place, and a uniform etching -varnish is formed. This last coating is extremely regular, and it is -wonderful to see the accuracy with which the lines have been covered. -Beginners are warned to pay attention to the careful cleaning of the -bright parts of the plate when brushing and dusting it; should any -resin remain behind, it melts on, and grows by degrees to a strong -yellow tint, which is very difficult to remove, but very easy to guard -against. Never forget to dust off the back. - -While the plate is still hot, lean it against the wall, face in, and -the back covered with a solution of shellac. - -Now the plate is ready for further etching, which is carried on for two -minutes in the first bath. At the end of two minutes, wash and examine -critically. In almost every case we may etch for a third, or even a -fourth time. It is, however, sufficient for the beginner to know that -he has sufficiently etched in two spaces of two minutes each, after -preparing with resin. Trying and examining with the finger-nail on the -black edge will show a fine relief. Should it be possible to etch for -a third space of two minutes, or even of one, without danger, it is -preferable to do so. It should be a rule to proceed as far as possible, -judging from the character of drawing and coating. Experience is easily -gained in two or three trials, since anything can be examined at any -moment. Beginners would do well to use a magnifying-glass with good -field of view in examining, when they can observe the most sensitive -portion, and |86| all changes may easily be noticed. The brush should -be used lightly, to prevent scratching. Usually, it is fastened at -right angles to a stick to protect the hands from the effect of the -acid. - -To raise the plates out of the tray, lay a gutta-percha thread into the -bottom of each tray, fastened at one end to the top edge of the tray, -projecting over the same on the other side. The plate is placed on the -thread while etching. It may be removed without touching the bath by -pulling the free end of the thread. - -As already remarked, the spreading of ink on a surface which is more -or less rough is difficult. For this reason the plate, when etched-on -after my method, is to be washed out with oil of turpentine. A strong -brush should be used for this, and some of the oil rubbed over the -plate without pressure. You must cause a dissolving, not a rubbing off, -of the coat. On continuing the addition of turpentine, the metal grows -bright. Take, then, a handful of the coarsest of pine-wood sawdust and -rub off the surface. This removes instantly every trace of turpentine, -leaving a clean surface behind. For the sake of security, pour on more -turpentine, rub with a somewhat softer brush, and remove again with -clean sawdust. - -It is important that the wash-table should always remain free from -sawdust, which latter should fall through the grating into a suitable -receptacle. If this rule is disregarded, the wash-brush will soon be a -conglomerate of sawdust and hairs. Sawdust and turpentine will stick to -the brush so tightly that a new brush will have to be purchased. - -Now we again examine our work. It is a mark of success if the relief -still shows its original smoothness in all its parts, and has nowhere -grown porous. All the parts must be clear in their correct proportional -strength, as seen in the transfer. - -The treatment of the plate from the time of transfer to the close -of the etching-on takes: for the saving of the edges and the white -portions of the drawing, 2 minutes; for preparing twice with asphaltum, -4 minutes; for varnishing the back and coloring the plate, 4 minutes; -for etching-on the lateral protection, 4 to 5 minutes; for preparing -twice with resin, asphaltum, and varnishing, 16 minutes; for renewed -etching, 4 to 5 minutes; and for washing, 5 minutes—that is, 33 minutes -in all. Add 7 minutes for inspection and retouching, and 40 minutes -will be the space allowed for etching-on. |87| - - -MIDDLE ETCHING. - -In order to give to the middle tints of the drawing the depth necessary -for printing, we begin with a new blacking-in. We need for this purpose -excellent, smooth, and hard rollers, which are immersed in minium and -linseed oil, and are then left to dry for a short time. Contrary to the -French method, we need here a thin composition for the etching ink, -obtained by concocting equal parts of paraffine, suet, beeswax, and -ordinary ink, prepared in an excess of good linseed oil. (Ready-made -color of right composition may be had of E. Liesegang, in Dusseldorf, -and other dealers.) - -This color, when of right composition, possesses the power of absorbing -resin-powder, and changes in combination with the same, when heated, to -a compact, very solid, yet brittle mass. - -Of this color, which is soft as butter, take a portion on a -knife-point, and spread it upon the smooth rollers, forming a perfectly -uniform layer. The complete covering is done by rolling, changing the -adjustment at intervals. When a perfectly uniform, oily coat is spread -on the color-slab and the rollers, begin rolling-in the washed plate. - -Do not exert any pressure, but roll, carrying the handles so as to -black the relief only from the surface of the rollers. Of course, -it cannot be prevented, and is of no consequence, if ink attaches -itself to the large white spots. Rolling continues till the oily brown -coating has deposited itself uniformly. Exercise care in order not to -get more ink on some spots than on others. The plate, now completely -rolled, is placed in the finely powdered resin, with which it must -be completely covered. For the space of two minutes the oily color -absorbs the powder, which should, therefore, be strewn on it and rubbed -off repeatedly. If saturation in the cold has taken place, dust off -lightly with brush and cotton, blow off well, and heat uniformly to -35° C. The resin should not melt now, but should only grow sticky and -combine intimately with the color, which forms the binding material. -This change is observed immediately in the change resulting in the gray -resin coat. As soon as the change occurs (beware of unequal heating), -again place the warm plate into the resin, saturate as before, dust -out, blow strongly on the bright, metallic spaces, to remove remaining -traces of resin, and heat to 50°–55° C. At this temperature cover the -film with fine asphalt powder, dust off as before, and heat to 65° or -70° C. In this condition the plate is again saturated with asphalt, -and the layer, after careful dusting and blowing, is heated until it -grows slightly |88| brilliant. Thus a complete coating is formed, and -the plate has the appearance of Fig. 6. The black spots represent the -dirt which has clung to the intensest lights, and must be removed. -But before attempting this, we varnish the back of our plate with a -solution of shellac, and cool it completely in water. - -[Illustration: Fig. 6.] - -Now take a very coarse scraper, ground with a sharp edge; hold it -between the index and middle fingers, and scratch away the dirt from -the light spots, making the edge of the scratcher draw the strokes -close together. The brittle backing breaks off finely, and in a few -minutes the dirt is removed and the plate is ready for etching. If -(which will only happen to beginners) the drawing should be scratched, -the exposed spot must be covered, by means of a brush, with a thick, -warm solution of asphalt in turpentine; the dirt which was scratched -loose is brushed off, and the plate goes into the bath for middle -etching for about three minutes. Brushing and washing follow in the -same way as in the previous operation. At the expiration of three -minutes inspect (with or without a magnifying glass); places that have -been uncovered must instantly be covered with asphaltum, as already -directed. Etching is continued till the lateral coating no longer -protects the first relief, which generally takes place after the third -period (in about nine minutes) in a new bath, but requires twelve -to fifteen minutes in an old one. It is proved by the existence of -only a narrow thread alongside of the relief. The moment can be well -ascertained. If we wish to be sure of it we may do so by exposing the -edge of the black rim at different places; the width of the thread -is then apparent, and a safe conclusion may be drawn from the single -spots as to the whole plate. If not enough middle etching has taken -place, the thread remains wide and requires an extraordinary clean -etching, which may lead to the picture growing thin and endanger the -finest lines. Care, then, is necessary to ascertain the right moment of -suspending the middle etching, and of continuing in the above-described -manner with oil of turpentine, brushing, sawdusting, and washing. -After drying and brushing off the sawdust with a strong brush, we -have the clean plate ready for examination. We observe the grade of -etching produced by |89| middle etching parallel to the contours of -the different parts, and can safely assert that the process has taken -its natural course. Etchings without real deep places (as high lights) -might here be _etched clean_—that is, might undergo removal of the -formed _etching grade_. Yet it is preferable to place the edge of the -drawing as low as possible, to prevent a tendency to crookedness, -so-called facetting, and to get a deep edge for nailing the plate on -wood. The outward appearance of the etching improves considerably, and -the cliché can be fastened much more securely. The chemigraphist must -endeavor to satisfy the demands of the printer in all respects, and -should omit nothing that serves to perfect his work. Thus only can he -gain a good reputation both for himself and for his work. - - -DEEP ETCHING. - -Having been successfully treated in the middle etching process, the -plate needs only depression of the larger light spots. Some simplify -this part of the work by cutting out the highest lights by means of -a chisel, reverse ground. This can easily be done after a little -practice, and often saves time and acid. Care should be taken with the -chisel; the plate should lie on a flat surface and the cutting twist -be executed lightly and regularly. If this course is decided upon and -is applied to the highest lights, proceed to the execution of the deep -etching. Such chiselling does not happen in my laboratory, since I -prefer to etch all plates alike to their normal depth. - -An excess of ink is now well spread over the rollers and the plate -is rolled in all directions. Close up all the middle tints and give -the acid room only in the densest lights. This coating is done by -warming the regularly covered plate to 31° C., and allowing the ink to -flow down rapidly and cover the recesses. A second coating with slow -manipulating of the rollers and manipulation of the handles without -pressure, will yield a sufficient coat from above. If, despite this, -certain parts should not be sufficiently blackened, rub on more ink -till the covering is sufficient and the side protection perfect. - -As in middle etching, we must proceed to the formation of an etching -varnish by dusting with gums, placing into resin, by lightly rubbing -this resin on in constantly renewed layers, till the absorptive power -of the ink ceases; then warming and dusting warm with the same resin to -complete saturation; then raising the heat as above, and dusting with -asphaltum to saturation, heating stronger and finally placing the hot -plate into asphaltum, which again secures all parts covered with ink -and resin. |90| - -At the different times of removing the dust, pay particular attention -to the bright metallic parts. Over-removal of dust removes resin from -the layer; under-removal leaves behind an obstinate yellow tint in the -bright spots. Practice and experience readily prove the best teachers -in this respect. - -The final heating of the etching varnish must be pushed so far that -an intimate connection is effected between all of its parts. This is -easily noticeable from the uniform gloss of the mass. While still hot, -the back of the plate is carefully varnished and cooling is promoted by -dipping it into cold water. - -[Illustration: Fig. 7.] - -But few spots are to be removed by chiselling (see Fig. 7), for the -rollers have only blacked the middle of the highest lights. These -spots, as indicated in middle etching, are scratched bright with a -chisel. It is important always to scrape off the white edge around the -drawing. Scratching of the plate does not even happen with beginners, -except in cases of gross carelessness. If it does happen, a good -covering with the turpentine solution of asphalt must be used. When -this is all done properly we proceed to etch. - -The process of etching by the aid of a brush is continued in periods -of five minutes each. It is necessary to examine the side covering -carefully at the end of every operation; a diligent brushing off of -the surface is also to be recommended. Etching is continued until, by -degrees, the lateral coating decreases and the grade grows narrower. At -this juncture—that is, after about five to six operations (twenty-five -minutes) the necessary depth is attained. In few cases (and almost -always with beginners), it happens that a single coating does not -suffice for deep etching without endangering the plate. In such cases -wash the plate, coat it a second time, and form a second etching -varnish. - -When the depth is satisfactory the plate is washed and the new grade -may be criticised. - -After a proper examination, we proceed to the - - -ROUND ETCHING. - -Its object is to remove the last formed grade. Coat the plate with a -very uniform coating of ink, corresponding to the one used in middle -etching. A |91| criterion for correct coating is, that only the grade -caused by middle etching be covered, while the grade from deep etching -must remain exposed. Remember also that in heating the plate a further -spreading is caused by melting. - -To the inexperienced it may happen that the grade caused by deep -etching is of variable width. These places must be removed by working -over with a graver before continuing, as otherwise we will not attain -symmetrical round etching. - -The plate prepared for the latter treatment is only dusted once in -resin, and then blown out. It is then heated to 45° C., and is dusted -and heated twice with asphaltum at increasing temperature, just as in -both the previous processes. Nothing now remains to be scratched away. -After having varnished the back, the plate is etched in the middle -etching bath two or three times for three minutes. At the end of each -period examine whether another whole period is necessary, or whether -rounding the plate requires less time. When this is over (several -parts, which perhaps were already finished beforehand, have been -covered), wash and approach the next problem, the removal of the grade -resulting from the middle etching. This is called - - -CLEAN ETCHING. - -Upon the clean, smooth rollers spread thick transfer ink and roll it -out perfectly. It is advisable to warm the stone previously with a -little alcohol, which promotes the working out of the color. When the -surface of the color has become perfectly uniform the plate is rolled -in slowly and without pressure. Pressure would deposit too much color -in the finest recesses, and prevent the clean etching and sharpening of -the same, thus causing lack of harmony in the prints. - -It is better to coat the shadows with a pad, as they require more color. - -The plate, thus blackened, is to be dusted once with the finest asphalt -powder, then freed from excess by dusting off and blowing until the -coating becomes brilliant. - -Clean etching then takes place in the bath for etching on, in -periods of one minute each, and repeatedly until the last thread has -disappeared. - -Now everything is ready for a proof, and for subsequent mounting. - -Fig. 6 shows a print of the little picture given during the process of -middle and deep etching, and admits of an instructive comparison during -the progress of the work. |92| - -Proofs are made from the cleaned plate (the back of which has been -scratched clean) in the following manner: Upon a good lithographic -roller place a quantity of the best ink and coat the etching uniformly. -Help the shadows along by dabbing on some ink with a leather pad. -When this is done, carefully rub off the excess in the lightest -spots, and fix the plate in the rolling-press; place on it a sheet of -well-calendered tissue paper, next a sheet of writing paper, a sheet -of Bristol paper, and a cardboard. With very little pressure (the -thickness of one cardboard less than in the transfer) draw it through. -If the print is too weak, place paper below, sheet by sheet. The -stronger spots may be blackened separately. - -[Illustration: Fig. 8.] - - -FINISHING AND MOUNTING THE PLATE. - -The first thing to be done is the removal of the black edge left by -etching and the sawing out of such spots in the drawing as were spared -for this from the beginning. The waste may be removed by means of -a circular saw or a fine-toothed carpenter’s saw. Do not, however, -forget to leave behind a margin of about three millimetres for the -purpose of nailing the plate to the wood. The edges must be smoothed -with a graver, filed and chipped off to a suitable plane, since sawing -produces a sharp edge. - -To remove the spots spared in the drawing, bore a hole through the -metal at that spot with an American gimlet, introduce a scroll saw, and -thus cut out the metal. The edge should be worked over with a dog-leg -chisel. - -By aid of the borer we also make the conical holes in the edge, through -which the nails are to be hammered. Elevations caused on the back of -the plate by boring should be removed by filing. - -The block of wood which is to raise the height of the plate to that of -type should be cut from perfectly dry maple, oak, or mahogany wood. -With the plate it must just reach to the top of the type; the sides -must be parallel, and all should be perfectly smooth. - -Cutting at right angles can be done with a circular saw or with the aid -of a mitre saw used by printers for such work. For exact examination -of height, |93| pass the block and zinc through the caliber-bridge -(Fig. 9). Roughen the base and top surface of the block with a -toothing-plane. When convinced that the block fits perfectly, nail the -etching upon it, taking care to drive the heads of the nails well into -the holes provided for them, otherwise they will show in the print. If -other small details are noticed, they may be removed with a dog-leg -chisel. - -[Illustration: Fig. 9.] - -This finishes the plate for delivery. - -In the expounded explanation of my chemigraphical method, the following -arrangement may serve the beginner as a guide to the manipulations from -the beginning to the end of the work: - -1. Planing the plate. 2. Grinding it out. 3. Freeing from fat, and then -testing its cleanliness. 4. Transferring the drawing to the metal. 5. -Preparing the metallic surface after transfer. 6. Strengthening the -transferred drawing by rubbing, rolling, or flooding it as directed. -7. Transmutation of the transferred drawing into a resisting etching -varnish by double besprinkling and burning in of asphaltum, subsequent -to covering the edges and large light parts, and after varnishing the -back. 8. Sharp or preliminary etching, strengthening with resin powder, -and finishing preliminary etching. 9. Washing and examining the work. -10. Coating with etching ink for middle etching. 11. Formation of the -etching varnish by double dusting and increasing burning-in of (_a_) -resin and (_b_) asphalt; varnishing the back. 12. Chiselling out the -lights of the picture. 13. Middle etching. 14. Washing and examining -the result. 15. Coating for deep etching. 16. Formation of etching -varnish by dusting, heating with increasing strength of resin and -asphaltum; varnishing the back. 17. Deep etching. 18. Washing out and -examining. 19. Coating for round etching. 20. Formation of etching -varnish by single dusting and warming of resin, and double dusting -and burning-in of asphaltum; varnishing the back. 21. Round etching. -22. Washing and examining the plate. 23. Coating for clean etching. -24. Formation of etching varnish by single dusting and burning-in of -asphaltum at a high temperature. 25. Clean etching. 26. Washing and -scraping the back. 27. Proofs. 28. Cutting out and mounting the plate. - - -|94| - -CHAPTER VI. - -HINTS FROM ALL SOURCES. - -Although the number increases almost every week, there are but few -persons who understand photo-reproductive processes in all their -details. Those who do, have been so chary of giving of what they know, -that our literature on the subject is very scanty indeed. Consequently, -as all the hints that are obtainable are very welcome, I have collated -a few from various sources, and make a mosaics of them here for the -general good. - -Every would-be photo-engraver, if he is not already a skilled -photographer, should obtain and study a good photographic text-book. If -he proposes to make his own drawings, he should also obtain Burnet’s -_Essays on Art_. The first will not only teach the best formula for -the production of negatives, but it will also enjoin the importance -of being careful, cleanly, and exact in all the manipulations. The -second will teach how to draw according to the best rules of art. -Remember always, the old injunction, _whatever you are, be best_! After -the regular photographic manipulations are well looked after, the -preparation of the drawing should have attention.—EDWARD L. WILSON. - - -AS TO THE DRAWING. - -There are two separate and distinct styles of drawing for reproductive -purposes, whether the artistic engraver be employed, or any of the -means of automatic engraving be used. These two methods are technically -known respectively as _fac simile_ drawing, and drawing in wash. The -former consists in the sole employment of lines, in which the shading -is to be produced as well as the outline of a picture. Every line and -mark that is subsequently to appear in the engraving must be traced -in the original. This description of drawing is applicable to wood -engraving, to line engraving upon copper or steel, as well as to all -the methods for automatically producing blocks for relief printing. The -line method is also universally adopted by etchers in _intaglio_. - -Successfully to prepare drawings for photographic reproduction it is -essential that some knowledge should be possessed of the fundamental -principles of |95| photography, as well as an acquaintance with the -capabilities of the particular process of production which is to be -employed. Thus, the material upon which the drawing is to be made -should be of such a character as will yield a strong and well-defined -contrast to the lines of the drawing; while the pigment employed for -the drawing should be as black as can be procured. White Bristol -board of fine surface, and the best India ink meet these conditions. -A blue-black does not form a desirable drawing medium, but the -introduction of red or orange into the composition should serve to -intensify the photographic image. To draw upon a dark orange-colored -paper with a pale blue-gray ink would be simply to disregard all -photographic principles, for the photographic value of the paper and of -the ink would be nearly equal, and the drawing would consequently be -lost. - -Uniformity of color in the drawing is also desirable, and the artist -should resist the natural tendency to express distance and to produce -his effects by diminishing the intensity of color in parts of his -picture. From a drawing uniform in color a satisfactory negative is -obtained; but, in the other case, the photographer must estimate an -average duration of exposure, and will rarely escape the dilemma -of some portions being overexposed while others are comparatively -undeveloped. This theory receives illustration from the fact that -very good subdued effects can be obtained from well-executed pencil -drawings, where this uniformity of color is preserved. A longer -exposure may be required, but every part of the picture will be equally -developed. - -To return to the matter of the paper used, color is not the only -important consideration. If the surface of the paper is irregular and -coarse in texture, such as painters in water-color delight in, good -results must not be expected. A negative, taken in the ordinary way -from a drawing made on such material, would inevitably reproduce all -the inequalities of the texture of the paper, to the manifest injury -of the more delicate parts of the drawing. In reproductions from old -prints or printed books, the conditions and character of the paper -present some of the greatest difficulties with which the photographer -has to contend. The ridges in the surface of the paper cast shadows -which are too faithfully reproduced in the negative. The employment of -a diffusive rather than a direct light is the usual remedy, but the -best way of dealing with the difficulty is that employed in the studio -of the Autotype Company. The original is laid upon the floor under a -strong light, and the camera set at an angle of forty-five degrees. - -Mr. Alfred Dawson informs me that he inclines to the opinion, founded -upon |96| his extensive experience and untiring experiment, that it -is desirable to get rid of the surface of the paper altogether, by -covering it with a substance similar to an enamel. - -In conclusion, the conditions required in the successful preparation of -drawings for photographic reproduction, may be thus briefly summarized: -That a sufficient photographic contrast should exist between the -pigment employed and the material upon which the drawing is made; that -a paper should be selected which is smooth and without water-mark, and -white; that the drawing material may be pencil or ink, in which blue is -not a component.—JAMES S. HODGSON. - - -FADING OUT THE PHOTOGRAPH. - -For newspaper line work excellent results may be obtained by drawing -over a photograph, and then fading out the photographic parts not -wanted. There are several methods, but the following is the most -simple and the easiest to manage: Make a weak solution of cyanide of -potassium and add a flake or two of iodine. When the drawing is made -with water-proof ink and on a photograph printed upon bromo-gelatine -paper the above solution flowed over it will at once cause such -portions of the image as have not been drawn upon with the ink, to fade -away and leave nothing but a fine ink sketch against a perfectly white -background.—ROBERTS & FELLOWS. - - -THE REVERSAL OF DRAWINGS (NEGATIVE PRINTING). - -This very simple and very safe method is to be recommended especially -for advertisements in papers and for titles of books, and can be made -both by aid of photography (by a transparency) and without it, in the -following manner: - -Make a copy, on copy-paper, of the drawing to be reversed, using an -ink of gum, glycerine, and aniline, and transfer it carefully, without -using too much water, when loosening. Dry the plate, and pour over it -a solution of 1 part of asphaltum, 1 part Venetian turpentine, in 18 -parts benzole; then allow to dry upon a plate. Place the plate into a -weak soda solution, and develop with a fine pad of cotton, till the -drawing stands clear. Ordinarily I employ the following method: A plate -prepared for transfer is uniformly cleansed with gallic acid and then -coated with gum, as in the case of blackening a transferred drawing, -while both solutions are left to dry spontaneously. This done, the -coating of gum and gallic acid is thoroughly washed off, and the plate -is carefully dried and gently warmed. The transferred drawing must be -made on |97| paper with an easily soluble layer composed as follows: -dissolve 100 grammes of wheat starch—_i. e._, starch _made_ of wheat—in -400 c.cm. of rain-water; raise 1 litre of water to boiling and dissolve -therein: 50 grammes of common salt, 75 grammes of glycerine, 50 grammes -of gelatine, and 25 grammes of molasses; when these are well dissolved -and taken up, add slowly the wheat-starch, stirring continually; then -allow to boil a short time so that we may dissolve it without an excess -of water after the ordinary transfer of the picture. When this has been -done, we wash it again with a soft brush and water, dry, dust twice, -and burn in thoroughly with asphaltum. Place the plate in a very weak -bath of nitric acid (10 cubic centimetres of acid to 1 litre of water), -and rock it lightly for about two minutes until the zinc changes color. -Then wash, dry, and warm. - -The combination of gum and gallic acid is broken up by this etching -in all those places which were not protected through the transferred -drawing, and the latter itself, in the subsequent blackening with -chemical India-ink, forms the coating and protection against a -combination of the zinc below. It is best to blacken it with a brush -and to warm the plate until the ink has become dry. Now moisten again -with gallic acid and gum, wash the plate (without great pressure) with -spirits of turpentine, rub on more of the solution of gum, and blacken -as usual. Practice will insure safe working by this method.—J. O. MORCH. - - -ETCHING APPARATUS. - -It does not come within the province of this work to instruct in the -preparation of inks and colors for etching or for printing, since such -articles are better purchased of the dealers ready prepared. In all -cases the choicest results are obtained by using the best apparatus -and the purest materials. There is no economy in “getting on” with the -“cheap.” - -A few hints as to some of the “tools” which are found convenient in -practice: For sifting the fine _resin dust_, a machine is employed, -known to sieve manufacturers as “the _composition_ sieve.” It consists -of the ordinary sieve, having on each side a cover with a bottom of -calf skin. The sieve-bottom is made of the finest silk texture. (See -Fig. 10.) - -For fixing and melting-in of the drawing on metal, I use a grate made -of a wooden frame with diagonal iron rods. This form is preferable -to the ordinary grate, because it allows the flame free access to -the metal plate. Inasmuch as the heat is strongest in the _centre_, -the cross-bars protect the centre of the plate from burning and from -warping. The source of heat is either an alcohol |98| lamp (Fig. 11) -in which cotton soaked in alcohol is ignited (the cover shown in the -drawing serves to smother the flame), or a strong gas flame (Bunsen -burner). The adoption of the latter mode is advisable. - -[Illustration: Fig. 10. The Sieve.] - -[Illustration: Fig. 11.] - -Formerly I employed a plain cast-iron heating-plate, with a gas or a -petroleum flame. The zinc plate, however, being in direct contact with -the hot surface, warped very much. I obviated that somewhat by covering -the heating-plate with a piece of wire-gauze. The strata of hot air -thus obtained between the cast-iron and the zinc plate heats the latter -equally throughout, and prevents warping. Still I prefer the direct -method. - -For freeing the plate from resin-dust, employ a strong pair of ordinary -bellows. - -The table (Fig. 12) for washing the coating material from the plate -consists of a heavy framework, upon which rests a wooden grate. A -massive table-board is not to be recommended, as the dirty sawdust -adheres to the same, while with the other it easily falls through the -openings into a box, and leaves the table free and clear. - -[Illustration: Fig. 12.] - -The measuring or calibre-bridge (see Fig. 7) serves to determine -accurately whether the ready plates have the height of type. A rule of -forty |99| centimetres will suffice for any plate. No plate should -leave the workshop without having been tested as to its thickness or -height on this instrument. - -The zinc plane is of ordinary construction, to the bottom of which -is attached a double layer of hard wood. The iron being arranged for -scraping can be inserted in a position just the reverse of the ordinary -plane. - -The “hand-bridge” is a strong ruler, thirty centimetres long, and five -centimetres wide, to the ends of which are fastened two blocks of wood -one centimetre high. It serves as a support for the hand in retouching. - -The rollers of the “chemigraphist,” and also the pads, are of greatest -importance. For etching by the French process we need a good, rough -roller, and a faultless, smooth one; for the Vienna process only the -latter is needed, in addition to a smooth, tight leather ball or pad, -such as was used in the art of printing prior to the introduction of -rollers. A perfectly smooth surface is obtained by covering the rollers -with a dryer, and allowing them to dry in the open air. A solution of -shellac with camphor, applied like furniture polish, also yields a fine -surface.—J. O. MORCH. - - -THE BEST DRYING BOX. - -After bichromatizing the gelatine sheet for printing the transfer -image, I proceed with the drying in a box constructed as follows: - -The box has four walls or sides of cloth, or any other stuff that -allows the air to pass through, and must have a solid bottom, which -will allow the attachment of a heating apparatus beneath it. In this -box is a cylinder which turns on its own axle, and which can be set in -rotation from the outside when the box is closed. Upon this cylinder -the gelatine paper, as we may call it, is placed, and the box closed. -A very equalizing drying is thus obtained, by keeping the heating -apparatus under the bottom of the box constantly at a steady, uniform -heat. By these means, it will be noticed: - -1. That an uneven running down of the chrome-layer is avoided, -and uneven drying also positively prevented in consequence of the -centrifugal force. - -2. That the drying by the draft of air is regulated, and at the same -time the air can be driven to a more rapid current. - -3. That the grain formed by this extraordinary method is unusually -perfect, and the nature of the grain more pleasing to the eye than when -formed by chlorides. - -4. That, as already stated, a rolling up or an uneven drying is hereby -|100| positively prevented, as the paper is placed tight around the -cylinder. And now for the main advantage: - -This so dried paper is ready for use, and, when exposed to light, under -a negative, produces a perfect and correct picture, which, when rolled -up with transfer ink and developed in water, is ready for transferring -direct on to the lithographic stone, or on to a metal plate, and to be -further proceeded with as usual.—EDWARD MEISSNER. - - -TO PRODUCE GRAIN ON A NEGATIVE. - -The negative is taken, and a solid pigment of Chinese ink sprinkled -on it with the Air Brush, by which it gets a wonderfully fine grain. -A coarser grain is made in a similar way, by sprinkling with a knife -over a tooth-brush that has been dipped in Chinese ink. The Air Brush, -however, will always be found the most suitable instrument, and now a -wide field for its use is opened to artists of all classes. Instead -of using Chinese ink, gamboge, or any other solid and well-covering -pigment may be used. - -For the practical photo-engraver, lithographer, photo-lithographer, -and other men of experience in photo-mechanical processes, no further -explanation is required. They will at once see the _superiority_ of -this process over everything that has hitherto appeared. After the -information we have just given, they will all be enabled to do work by -this process. It will henceforward be easy to produce photo-lithographs -for lithographic printing as well as printing plates for the type press -_without difficulty, in a short time, and at trifling expense_.—FRED. -BUEHRING. - - -ON THE USE OF ACIDS. - -A few hints on use of the acids will form my contribution to your work: - -In order to obtain a proper resistance and firmness in the lines, it is -necessary to prevent the acid from making the base that supports them -too thin, and to strengthen the base by giving the depression the form -of a V, and the base itself the form of an A. The depth must be great -enough in the broad blanks to prevent the roller from sinking (although -there is no danger of this when the lines are close together), and thus -soiling them. A useless depth between very thin sides might weaken -them; but, in the process employed, the attack by the acid continues -only in proportion to the width of the spaces to be excavated. |101| - -These results are obtained as follows: The prepared plate bearing the -design is inked with a thick ink containing a little wax, and is placed -in a trough with acidulated water, which slightly attacks the metal. - -The trough is mounted so as to rock, and is kept in motion by a lever -actuated by a steam motor. The water moves to and fro over the entire -surface, and keeps continually washing the parts that are not protected -against its action. No local saturation, therefore occurs, and the -continuously renewed liquid attacks the bottom as well as the sides -of the hollow. The sides would soon be rendered too thin were the -biting-in too long continued, and for this reason the first attack -is made with great care. It is upon this that depends the sharpness -of the proof. The acid used is nitric, so dilute that it is scarcely -perceptible to the taste, and in the proportion of about one and a half -ounces to a quart of water. The acidity is kept up by a small quantity -of acid of 36°, that falls drop by drop from a bottle provided with a -cock. After about a quarter of an hour, the plate is taken out, and the -operation repeated as generally directed. - -Remember this: At every new biting-in the acidity of the bath is -increased, and, when the broad parts alone remain exposed to the -attack, acid of 6° B. may be used. In this state, the zinc plate, taken -from the bath and washed and dried, is treated with benzine, and then -with potash, in order to remove all fatty matter. It may then be seen -that the sides of the hollows do not exhibit a regular sloping surface, -but a series of ridges corresponding to the series of bitings-in. As -these might take the ink, and affect the purity of the lights and -shades, it is necessary to remove them by an operation analogous to -the first, but carried on quickly in an opposite direction. With this -intent, the plate, well cleaned and heated upon the iron table, is -inked while hot, with a composition formed of two parts printing ink -and one part each of resin and beeswax. This ink, which can be used hot -only, descends along the sides of the depressions, and when it has got -half way to the bottom the plate is cooled, and the inking is renewed -so as to well cover the entire surface. - -It must not be believed that in practice these operations can be -conducted without extreme care. A want of attention, unsuitable ink, or -a too high or low temperature, may lead to the loss or poor execution -of the piece. It is often objected that the lines in this style of -plates have not the boldness of those produced by the graver. It is -not for us to answer the question whether this is a merit or a defect; -artists generally endeavor to employ paper with an irregular and -granular surface, and which is far from giving such boldness; |102| -and he perhaps would be poorly appreciated who should present upon -glazed paper a drawing made with the pen and resembling a picture made -with the graver. It is the artist’s business to produce the work such -as he desires the Gilloteur to render it.—GILLOT. - - -MULTIPLICATION OF ZINC ETCHINGS BY GALVANIC MEANS AND BY STEREOTYPING. - -Multiplication of printing-blocks by galvanoplastic, or stereotyping, -is not so easy as in case of woodcuts or type. The main difficulty -lies in some peculiarities of the process of etching, especially if -the plate has been produced by the French method. The reproduction -of a form is often impossible, since the matrix is caught on certain -rough spots and then tears, thus rendering galvanoplastic reproductions -imperfect. - -Having very frequent opportunity of making matrices from plates, I call -the etcher’s attention to several points upon which the success of the -work depends. On no condition whatever may any parts of the plate be -corroded from beneath, as wax or gutta-percha will invariably tear when -lifting off the impression (mould). - -In the second place, the bottom of the etching must be perfectly -smooth, not rough; the single grades, left by etching, must be removed, -and the lines must incline perfectly smooth toward the depth of the -etching. - -In stereotyping, the process of drying presents special difficulties, -since with heat the wood warps and distorts the plate; the cold -process, on the other hand, does not give equally sharp impressions. -For this purpose I have mounted the plates on lead instead of on wood, -and am thus enabled to get sharp impressions and to apply hot drying. - -Instead of paste, I employ light magnesia; instead of oiling the plate -before planing or rolling it in, I give it a high polish with stearine -oil and rouge by means of a circular brush, and brush it once more with -talc. Thus I am sure of success. - - -PREPARING ZINC PLATES ON THE PRINTER’S PRESS. - -A wood-cut gives the _outrunners_ of the finest portions in a plane -which runs downward; an etching, on the contrary, shows the whole -engraving in one plane. According to this the _outrunners_ (the -borders) often print somewhat hard, unless care is taken to alleviate -this fault. This will be easy to the experienced workman. |103| - -Starting from the fact that a zinc plate is easily bent, place -something under the back of the _heavy_ portions in mounting, and when -nailing drive the nails tight in the white lights and on the edges; -thus the borders are deepened, and _print_ softer. - -In this manner an experienced and practised hand can produce effects -impossible in any other way. - -For printing on rotary machines, galvanos are used in many places. But -a zinc plate may be excellently fastened in the following manner: - -Clean the back well and solder the back with soft solder, as is -customary in galvanic backing. Then attach it lightly to its place on -the wooden or metal block, hammer or roll in the plate without paying -special attention to the zinc plate, dry the matrix, and lift it from -the form. After preparing for casting take the zinc plate from the -wooden block, bend it while hot, put it back into its position in the -matrix, cover the edges with tissue paper and paste, dry the edges -with an iron, place into the casting apparatus and cast as usual. In -this manner the zinc plate (metal, cast from a matrix) is in place at -exactly the height of the type and will print excellently. (The face -is to be slightly oiled before fastening in the matrix, to prevent any -sticking of the lead.) - -As a _cover_ for the printing cylinder, I have always found paper most -serviceable, although covers of English leather are also advantageous, -especially for large editions. I should not recommend felt. - -The rollers for printing zinc plates should be held with somewhat -stronger tension than for printing of wood-engravings. - -As a method of preparing, I recommend the gradating of the lights and -shades, known to every intelligent machinist. Wherever possible, highly -calendered paper should be used, as it gives the best results. - - -ETCHING WITH SULPHATE OF COPPER SOLUTION. - -Nitric acid may be replaced by sulphate of copper, especially in -the first periods of etching, and etching can be obtained both in a -galvanic way and by easy shaking of the tray. The sulphuric acid of -the copper sulphate combines with the zinc and the copper, and when -liberated, precipitates as an amorphous, muddy substance. - -Although this process has almost entirely fallen into disuse, the most -important points are treated of below. - -_The bath._—Dissolve pure copper sulphate (of the strength of -9° Beaumé) at a temperature of 15° C. Etch galvanically in this bath -by placing in it a clean |104| copper dish. The plate prepared for -etching as per page 84, is rubbed bright at the four corners and four -S-shaped narrow strips of sheet copper are so fastened to the bright -zinc that the S-shaped end rises about three millimetres over the -picture. Then place the plate face downward for three minutes into the -bath, above the copper plate, which is electrically connected with the -zinc by brass strips, so that instantly a strong galvanic current is -set up. The etchings are found to be very satisfactory and interesting. -In three periods (nine minutes) a beautiful preliminary etching is -obtained with rather perpendicular faces. - -I cannot recommend etching by shaking, as the sediment causes rupture -of the finest lines. - - -PROCESS FOR HIGH ETCHING IN RELIEF. - -Experienced etchers can also apply their art to the reproduction of -drawings by means of the printer’s press, in the following manner: - -A plate, ready for etching and free from grease, is cleaned with weakly -acidified water, the remaining water drawn off with a blotter, and the -plate gently heated. By means of a pad a fine paste of graphite is -rubbed upon the surface; it is then moderately heated and a very thin -gauze-like layer of warm white wax is applied to the graphite surface. -After cooling the plate, spread upon it a coat consisting of the finest -orange-colored chrome yellow (rubbed to a fine dough with water and -gum). In this ground layer we can erase as for deep etching. - -Brush the finished surface with writing ink dissolved in benzine (using -a fine wide brush). The plate should be warm. Take a pad made of -cotton, dip it into water and work over the surface in small circles -until the image has become well developed. From this point we can -continue according to the usual method. - -J. O. MÖRCH. - - -THE RUNNING OF A WORKSHOP. - -The great competition demands of every chemigraphical business a -ready, productive organization, which is also attentive to the rules -of economy. In following out the latter it is advisable to aim at -a division of labor. By giving to the single workmen more practice -in each particular manipulation, the quality of the work is also -promoted. To secure a lucrative trade, we need the following helpers: -1. A foreman thoroughly acquainted with the whole process. 2. A -photographic assistant, who is skilled especially in straight line -|105| reproduction, and who aids in the copying of negatives. 3. A -carpenter, at the same time polisher of the zinc and finisher of the -plates, who will also assist at other things in general. 4. A first -manipulator, who understands blacking of the plates and the examination -of the same throughout the whole process. 5. A man to form the etching -varnish on the plates. 6. A man to scrape off. 7. A man to etch. 8. -One to wash plates and to make himself generally useful. With the aid -of such a staff it is possible to produce 2000 square centimetres of -etching daily, and by the addition of a ninth assistant the capacity -can be raised to 3000 square centimetres. - -A first manipulator can be trained in three months, a carpenter in the -same time, and the others in four to six weeks. - -The head of the establishment will, of course, be doubly busy during -these first months. Upon his abilities depends the success of the whole. - -I think it is inadvisable to introduce etching into all the printing -establishments, as production on a small scale is far more expensive -and less satisfactory. But it _is_ advisable to add to the chemigraphy -a small lithographical laboratory.—J. O. MORCH. - - -SOME WRINKLES AND DODGES. - -As I had to stumble through to success like many others, I gladly give -a few little items of practice which may speed the work of others. I -like this for a sensitizing solution: - - Bichromate of Potash in powder 1 ounce. - Water 15 ounces. - Alcohol (950) 4 ounces. - Liquor Ammonia 1 ounce. - -After I have sensitized the gelatine transfer paper I increase the -surface quality by laying it upon a glass plate which has been heated -_very slightly indeed_ with vaseline. I use a squeegee to secure close -contact and then stand it up to dry, say over night. A slight start at -one corner with a knife point will cause the paper to leave the glass -readily. - -It pays always to get the best material. Nothing is worse than a bad -quality of zinc. I use No. 10. A strong, well-made clotheswringer will -answer for a time, for making transfers, when a lithographic press is -not convenient. The pressure should be uniform. - -Learn to be systematic until you are familiar with all the details -of the work. It might be well for you to make a numbered list of the -necessary operations |106| and paste it up where you can see it and -refer to it handily. Accustom yourself to having a place for everything -and everything in its place. I have seen many an etching lost by -disregard of this rule.—C. W. ROCHE. - - -CARBON PRINTING. - -In Chapters III. and IV. on engraving on copper, the resist and relief -are made by what is called in photographic nomenclature the carbon -process—that is, printing in gelatine to which has been added a -suitable pigment. This pigmented gelatine, spread upon paper and dried, -is known in commerce as carbon tissue, and is sold of various colors -and degrees of density as regards the quantity of pigment incorporated -with the gelatine. For our purpose that tissue containing the minimum -quantity of pigment is the best (this only applies to the resist or -relief on the copper, not to the transparency necessary for printing -the resist from; in this case what is known as transparency tissue must -be used, and that is made with the maximum quantity of pigment (India -ink) incorporated with the gelatine), but as the subject of making -transparencies in carbon has already been treated of, the present notes -will be confined entirely to developing carbon prints upon copper for -resists (Chapter III. for reliefs Chapter IV.). - -The carbon tissue of commerce is not sold in a sensitive condition; -therefore, the first care will be to render it sensitive to the action -of light, which is done by immersion in a solution of bichromates of -potash and ammonia. - -First of all dissolve in eighty ounces of water one and a half ounces -of bichromate of ammonia, and one ounce of bichromate of potassium, and -filter. Then cut the carbon tissue into suitable sized pieces—_i. e._, -pieces a little larger than the subject on the transparency or negative -to be used, and a little smaller than the copper plate upon which it -is intended to develop the carbon print; next select a sufficient -number of glass plates quite free from scratches a little larger -than the pieces of tissue, now clean these glass plates carefully by -polishing with clean linen or silk cloth free from lint, then dust over -with French chalk and again well polish; then coat with thin plain -collodion, and when the film is well set place the collodionized plate -in clean cold water until the greasy appearance that shows on the first -immersion in the water has disappeared. - -Place the filtered bichromate solution in a clean dish, then immerse -the pieces of tissue, one at a time, taking care that no air bells are -allowed to |107| remain upon the surface; if any form, remove them -by bursting them with the fingers. After the tissue has been in the -solution for three minutes, take one of the collodionized and washed -plates from the water and remove one of the pieces of tissue from the -bichromate bath, place the two face to face, lowering the tissue gently -down upon the collodion film, then place the glass plate upon a bench, -lay a piece of Macintosh cloth (larger than the plate) over the tissue, -and with a squeegee gently scrape along the Macintosh; this will bring -the carbon tissue into contact with the collodion film, and also expel -superfluous bichromate solution, but care must be taken not to remove -too much of the bichromate else the tissue will be insensitive and -print hard. The plate is now placed upon a rack, and all the remaining -pieces being done in the same way are also placed upon the rack. - -The tissue being thus squeegeed into optical contact (the squeegee is -made with a strip of soft rubber fixed between two pieces of wood) with -the collodionized glass, it must be dried in the dark room in a current -of warm air, not higher than 60° F., else the pigmented gelatine will -melt and be useless (bye the bye, the bichromate solution in hot -weather should be iced so as to keep the temperature below 50° F.). - -When the tissue is dry it is stripped from the glass and stored in a -tin tube, and care must be taken to keep it away from the light, as -if the tissue be once exposed to the light even for a short time, the -action will go on in the dark. - -In treating of the transparencies, it is mentioned that the subject on -the transparency or negative is marked, this being necessary to form -what is called a safe edge to the carbon print. If such a safe edge be -not provided, the carbon print will not adhere to the copper during -development; therefore, the extreme edges of the tissue must be guarded -from the light during the exposure in the printing frame. - -The exposure to light under the negative or transparency must be timed -by means of an actinometer, which may be improvised by dividing a strip -of tracing paper into ten spaces, and numbering these spaces so: - - ─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬────── - │ │ │ │ │ │ │ │ │ - 1 │ 2 │ 3 │ 4 │ 5 │ 6 │ 7 │ 8 │ 9 │ 10 - │ │ │ │ │ │ │ │ │ - ─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴────── - -Write the figures with good black ink and then cut other pieces of -white tracing paper into strips of the same width. |108| - -Now lay the piece of tracing paper with the numbers on it, upon a -piece of glass 4-1/4 × 3-1/4 inches, and fix it in the centre, then -place thicknesses of tracing paper over this so that space 2 has three -thicknesses of tracing paper, space 3 five thicknesses, space 4 seven -thicknesses, space 5 eight, space 6 nine, and so on up to 10. Now if a -piece of ordinary sensitive albumen paper is put into a frame behind -this screen, it will form an actinometer, and when, after exposure to -light the figure 5 is just visible, five tints are registered. - -This actinometer will with practice enable the operator to judge when -the carbon tissue has been exposed sufficiently long; the only guide -that can be given, is to err on the side of overexposure rather than -underexpose. - -The carbon tissue being exposed, it is removed from the frame, and -placed in clean cold water; then as soon as it begins to uncurl itself, -the copper plate is placed in the water, and the two are brought into -contact, the tissue adjusted in position upon the copper, then removed -from the water, and a squeegee applied vigorously to the back of the -tissue, applying the squeegee first one way and then the other. - -Now allow to stand a few minutes, then immerse it in water at a -temperature of 90° or 95° F., and in a few minutes the pigmented -gelatine will begin to ooze from under the paper backing, which may now -be stripped off and thrown away. The copper plate may now be raised -and gently laved with the hot water, or it may be allowed to remain -until the whole of the soluble gelatine is dissolved away, leaving the -picture upon the copper plate, which is rinsed in cold water and dried. - -For the purpose of copper plate work, the image must be thoroughly -well exposed, every detail being impressed, else it will be impossible -to get a good photogravure; therefore, until the operator thoroughly -understands the use of the actinometer it will be as well to make a few -prints upon a piece of opal glass. - -Carbon tissue does not keep in a sensitive condition more than a month, -under the most favorable conditions, the general time perhaps being a -week. The first sign of deterioration is generally shown when trying to -mount upon the copper, after soaking in cold water, the tissue refusing -to adhere after the application of the squeegee. The best way to test -the sensitive tissue is to take a small piece and immerse it in cold -water for a minute, then put it into water at 95°, and, if the coating -dissolves off the paper the tissue is all right; if it does not, it is -useless. Tissue will generally be found at its best about |109| three -days after sensitizing, and will gain rapidly in sensitiveness daily -afterward. - -Carbon tissue can be made at home, the following being the formula: - - Gelatine (soft) 10 ounces. - Sugar 4 ounces. - Water 30 ounces. - -Dissolve the gelatine at as low a temperature as possible, then add -the sugar and churn thoroughly; then add sixty grains of India-ink, -previously dissolved in a little water, again churn, then strain -through muslin into a dish (which dish is placed in another containing -hot water). Now take two sheets of paper, grasp one end tightly and -drag them rapidly through the tissue compound, and directly they are -lifted clear of the solution let an assistant grasp the bottom and you -dropping the top, will reverse the sheets and keep the gelatine on the -surface of the paper; when the gelatine has set, divide the two sheets -and hang up to dry; when dry the subsequent proceedings are the same as -for commercial tissue. - - -COLAS’S BLACK PROCESS. - -This process will often be found useful to reproduce a drawing on -yellow tracing-paper, so as to give a more suitable copy to photograph -from. - -Coat with a fine sponge a hard, well-sized paper, with - - Water 300 parts. - Gelatine 10 parts. - Perchloride of Iron (dry) 20 parts. - Tartaric Acid 10 parts. - Persulphate of Zinc 10 parts. - -and dry in a dark-room. - -When dry, expose under the tracing until the greenish-yellow tint of -the paper has disappeared, except where covered by the opaque lines. - -Development is effected in a bath made by dissolving 20 parts of gallic -acid in 200 parts of alcohol and 1000 parts of water; then wash in -plenty of clean water. - - -MORDANTS FOR ETCHING. - -I. MORDANTS FOR STEEL.—Nitric acid forms the basis of most fluids for -etching steel as well as for other metals. Acetic acid and alcohol are -sometimes added, and some formulæ contain nitrate of silver, corrosive -sublimate, salts of |110| copper, etc. Iodine is also a most efficient -mordant for steel, and Mr. Fox-Talbot used the chlorides of iron and -platinum for etching his plates through the coating of bichromated -gelatine. - - -_Plain Acid Mordant.—(Kruger.)_ - - First biting: - Muriatic or Nitric Acid 1 part. - Water 8 parts. - - Stronger: - Acid 1 part. - Water 4 parts. - - Deepest: - Equal parts acid and water. - -_Kruger._—Chromic acid, diluted according to the effect to be produced. -This also serves for zinc, copper, and brass, and bites with great ease -and certainty, making a good vertical cut. - - -_Ed. Turrell._ - - Glacial Acetic Acid 4 parts. - Absolute Alcohol 1 part. - Nitric Acid (specific gravity, 1.28) 1 part. - -The acetic acid and alcohol are mixed and allowed to stand for half an -hour, then the nitric acid is added very gradually. This mordant is -applied from one to fifteen minutes, according to the strength desired, -and may be strengthened by adding nitric acid. - - -_Etching Solution with Alcohol._ - -Alcohol seems to be added with the object of softening the action in -the first biting, and of making the mordant bite at once. For etching -Niepce de St. Victor’s asphaltum plates, M. Lemaitre used, for the -first biting: - - Nitric acid, at 36° 1 part. - Distilled Water 8 parts. - Alcohol, at 36° 2 parts. - -And finished off with nitric acid and water, without alcohol. - - -_Etching Solution with Nitrate of Silver._ - - Alcohol 6 parts. - Distilled Water 9 parts. - Pure Nitric Acid 16.6 parts. - Nitrate of Silver 0.83 parts. |111| - -The liquid improves by keeping. Before beginning, wash the plate for a -few seconds with dilute nitric acid (at four per cent.), then apply -the above mordant for about three minutes, and wash off with distilled -water containing six per cent. of alcohol. Repeat the biting as often -as may be necessary, well washing between each operation. - - -_Deleschamps.—Glyphogen._ - - Acetate of Silver 8 parts. - Rectified Spirits 500 parts. - Distilled Water 500 parts. - Pure Nitric Acid 260 parts. - Nitric Ether 64 parts. - Oxalic Acid 4 parts. - -This is recommended as being free from the defects of many of the other -mordants, and as giving a clean vertical bite. - -Several formulæ contain salts of copper. - - -_Roret._ - - Nitric Acid 62 parts. - Distilled Water 125 parts. - Alcohol 187 parts. - Nitrate of Copper 8 parts. - -Iodine is recommended as a very efficient mordant for steel, being free -from the inconveniences caused by the disengagement of gas, as when -biting with nitric acid. Messrs. Schwarz and Boehme give the following: - - Iodine 2 parts. - Iodide of Potassium 5 parts. - Water 40 parts. - -This may be further diluted up to 40 parts more water, for etching the -finest lines. It gives good deep lines, sharp, and with clear edges -even, for the finest and closely ruled lines have no tendency to run -one into the other. - -The following resembles the etching fluids for copper, commonly known -as “Dutch mordant.” - - -_Cooley._ - - Hydrochloric Acid 5 parts. - Water 95 parts. - -Mix and add: - - Chlorate of Potash 1 part. - Water 50 parts. |112| - -_Cooley._—For electric etching with the battery, a solution of common -salt is used. - - -II. MORDANTS FOR COPPER.—The most useful mordants for copper are nitric -and nitrous acids, more or less diluted with water. Latterly, however, -a mixture of chlorate of potash and hydrochloric acid, known as the -“Dutch mordant,” has come more into use. For some purposes, perchloride -of iron in solution is a useful mordant, particularly in photographic -work with gelatine films. These two latter mordants bite more quietly -than the acids, so that the lines are not so much enlarged, and -there is not the same risk of close lines running together and other -inconveniences caused by the evolution of bubbles of gas. - - -_Acid Mordants.—(Lalanne.)_ - - Nitric Acid, at 40° 1 part. - Water 1 part. - -With a little old etching solution added, or pieces of scrap copper. - - -_Malaret._ - - Nitric or Sulphuric Acid 1 part. - Saturated Solution of Bichromate of Potash 2 parts. - Water 5 parts. - -Fizeau used for daguerrotype etching a mordant composed of nitric, -nitrous, and hydrochloric acids. - - -_Dutch Mordant._ - - Fuming Muriatic Acid (specific gravity, 1.190) 10 parts. - Water 70 parts. - -To this add a boiling solution of - - Chlorate of Potash 2 parts. - Water 20 parts. - -This may be diluted with from 100 to 400 parts of water as required. - -Perchloride of iron, more or less diluted in water, is, according -to Hamerton, an excellent mordant. It bites deep and clear, without -enlarging the line much, and there is no ebullition, as with nitric -acid. It is particularly useful in photographic etching through -gelatine, as the latter is insoluble in it. - -In most cases the mordant is flowed over the plate, or kept moving -on it in the same way as a photographic developer. Such mordants are -generally used for finishing off and deepening the light tints, and are -called _eau fortis à couler or à passer_. The following formulæ are -given: |113| - - -_Roret.—(Abraham Rosse’s.)_ - - Strong White or Distilled Vinegar 3 litres. - Sal Ammoniac 180 grammes. - Common Salt 180 grammes. - Pure Verdigris 120 grammes. - -A little oxalic acid is sometimes added. The solids are ground up, and -boiled in the vinegar. Acetic acid at 3°, or pyroligneous acid, may be -used in place of vinegar, and, if too strong, more vinegar should be -added. - -The following, used by Callot and Piranesi, is similar and prepared in -the same way: - - Strong Vinegar 8 parts. - Verdigris 4 parts. - Sal Ammoniac 4 parts. - Salt 4 parts. - Alum 1 part. - Water 16 parts. - -For relief etching use only 10 parts of water. - - -_Relief Etching._ - -For etching copper in relief, the following glyphogen is recommended by -Deleschamps: - - Nitrous Acid, at 30° 2 ounces. - Acetate of Silver 6 drachms. - Hydrated Nitric Ether 16 ounces. - -The nitric ether is prepared by mixing two ounces each of nitric acid -and alcohol, and, when the reaction commences, stopping it by adding -eight ounces of distilled water. - - -_Tint Etching._ - -Flour of sulphur mixed with oil forms a good composition for etching -tints. It can be applied with a brush. For a flat tint, Hamerton says -“Oil the plate liberally with olive oil, and blow flour of sulphur upon -this.” The sulphur, if allowed to remain on the plate, will produce a -flat tint, more or less deep in proportion to the time it remains. - -Roret gives the following formula for tint etching: - - Bay Salt 2 parts. - Sal Ammoniac 1 parts. - Verdigris 1 part. - -These are pounded together, and the mixture kept in a bottle. |114| - -When required for use, grind up a little in a glass with some syrup of -old honey, so as to make a mixture which flows readily. It may be used -with a brush like a color. It is used after the bitings of aquatint -plates with acid, to give finish and vary the tints. - - -_Fielding (for aquatint)._ - - Nitrous Acid 1 part. - Water 5 parts. - -For the strongest touches, nitrous acid and water, equal parts, applied -with a feather or brush. No. 19 may also be used for this purpose, -either with or without a little gum. - - -_Hamman._—Dilute nitric acid at 12° (sp. gr. 1.09), mixed with: - - Distilled Water 12 parts. - Alcohol 3 parts. - -This is said to give a grain in biting, so that the ordinary grained -ground may be dispensed with. - - -_Electric Etching._ - -It has frequently been proposed to etch by means of electricity, and in -some cases it may be an advantage to do so. - -The copper plate to be engraved is attached to the positive pole of -a suitable battery and placed as anode in a solution of sulphate of -copper, or in water acidulated with sulphuric acid. - -In suitable cases, different degrees of depth may be given, putting -parts of the anode and cathode nearer together or further apart. - -Grove etched daguerrotype plates with a single pair of Grove or Bunsen -cells, by inserting the plate to be etched, and a platinum plate of the -same size, in a wooden frame having two grooves a quarter of an inch -apart. - -The daguerrotype having been attached to the battery as anode, and the -platinum plates as cathode, the frame is immersed in a suitable vessel -filled with - - Hydrochloric Acid 2 parts. - Distilled Water 1 part. - -Contact is made for about half a minute, after which the plate is -removed from the acid, washed thoroughly with distilled water, then -placed in a solution of hyposulphite of soda or ammonia, and the -deposit removed from the surface |115| with gentle rubbing with -cotton. It is again rinsed with distilled water and dried. - - -MORDANTS FOR ZINC. - -The comparative cheapness of zinc would give it an advantage over -copper or steel for engraving or etching with the graver or point, -but it does not seem to be recommended for these purposes. It is -hard to cut with the graver, and, though it bites easily, it is not -suitable for fine work. Another defect is that it will not stand a -long impression; but this may be overcome by surfacing the plate with -copper. The principal uses of this metal for printing purposes are for -surface printing or zincography in the same manner as lithography, and -for the process of biting in relief, and zinco-typography or Gillotage, -now so largely employed as a substitute for wood blocks. It can also -be engraved very delicately in the same style as engraving is done on -stone, through a coating of gum. - -The etching fluids for zinc are of two entirely different kinds: -first, mixtures of gum and weak acids used for preparing plates for -zincographic printing in the lithographic press, or for preliminary -inking preparatory to being bitten in relief by the Gillotage process; -and secondly, mineral acid, more or less dilute, used for biting in -relief and ordinary etching. - - -_Zincographic Etching._ - -This kind of etching is more of a preparation of the plate for printing -than engraving or biting, the object being merely to fill up the pores -of the metal with gum, and prevent it receiving printers’ ink from the -roller elsewhere than on the lines of the drawing. - -The solution most commonly employed for this purpose is a mixture -of gum and decoction of nut-galls, in use at the Ordnance Survey -Office, Southampton, and given by Sir Henry James in his work on -_Photo-zincography_. It is prepared as follows: Four ounces of Aleppo -galls are bruised and steeped in three quarts of cold water for -twenty-four hours; the water and galls are then boiled up together, and -the decoction strained. The gum-water should be about the consistency -of cream. One quart of the decoction of galls is added to three quarts -of the gum-water and to the mixture are added about three ounces of -phosphoric acid, which is prepared by placing sticks of phosphorus in a -loosely corked bottle of water, so that the ends of the sticks may be -uncovered. The oxidation of the phosphorus produces phosphoric acid, -which dissolves as fast as it is formed. |116| - -The etching solution should only just mark a piece of plain zinc. - -In Richmond’s _Grammar of Lithography_ the following modifications of -this formula are given: - - Decoction of Nutgalls 3/4 pint. - Gum Water as thick as Cream 1/4 pint. - Phosphoric Acid Solution 3 drachms. - -Boil one and a quarter ounces of bruised nutgalls in one and a quarter -pounds of water till reduced to one-third, strain, and add two drachms -of nitric acid and four drops of acetic acid. - -Richmond recommends, however, the use of a simple decoction of galls -without acid, and gumming in after etching. - -Scamoni has the following, by Garnier: Boil about one and a half ounces -of bruised gall-nuts in a pint of water till reduced to one-third, -filter, and add two drops of nitric acid, and three or four drops of -muriatic acid. For very fine work this may be weakened with water. It -is applied for about a minute, then washed off, and the plate gummed. - - -_Zinco-typographic Etching._ - -In biting zinc plates in relief, the acid generally used is nitric of -different degrees of strength, according to the nature and state of the -work. - -After the transfer is made, the plate is etched with one of the -foregoing preparations, then inked in and dusted with finely powdered -resin, which adheres only to the lines. This procedure is followed -after every biting, the plate being warmed to melt the resin and inky -coating, so that it may run down between the lines and protect them -from the undercutting action of the acid. - -Kruger, in his _Die Zinkogravure_, recommends for the first relief -etching, nitric acid 30 to 40 drops to 100 grammes of water, applied -for five minutes. For each subsequent etching, 8 to 10 drops of acid -are added for each 100 grammes of water, and the time is increased, -from five to fifteen minutes. For the final etching of the broad lights -he uses: - - Muriatic Acid 4 parts. - Nitric acid 1 part. - Water 16 parts. - -To soften down the ridges between the lines the plate is inked and -dusted as before, and etched with dilute nitric acid at five per cent., -applied for a |117| minute, and the inking, dusting, and etching -repeated as often as may be necessary. - - -THE DIFFERENCE. - -Finally, in this department, only the novice will require an -explanation of the varied productions possible by means of the -processes already given. As actual examples, reference may be had to -the illustrations in this work. Figures 1, 2, and 3 are specimens of -line work, zinc etchings made from pen and ink drawings. The figures in -the following chapter were made in the same way. - -[Illustration: Fig. 13.] - -Figures 4, 5, 6, and 7, as well as some others, are zinc etchings -reproduced from Mr. Mörch’s work. With them more effort has been made -to secure half-tone by a variety and quantity, or filling, in of lines. -The example below was made by using the objects (ferns) themselves as -the negative, without any interposition from photography, and shows one -of the possible applications of zinc etching. It is delicate work and -is very beautiful when carefully done. An example of true half-tone, -obtained in the manner described in Part II., is the one which follows. -It was made by Mr. F. E. Ives, the earliest inventor of a half-tone -process, several years ago. The larger examples of half-tone work which -appear in this book are made after the most modern fashion and formulæ, -as described in Part II., and will serve well to show what the worker -in this fascinating process may expect to reach after patient and -persistent experiment. When we look upon Fig. 1 and see the very best -that zinc |118| etching could do a few years ago, and compare it with -the Mosstype and other half-tone pictures now possible, we may well -wonder at the growth of the art. - -[Illustration: Fig. 14.] - -It has been attained by the careful and persistent plodding of a few. -Many a method has been discarded for a newcomer, and there is no -telling what may come next. Photography has about revolutionized the -illustration of books and magazines, and has made the newspaper far -more attractive than it was a few years ago. It has made the faces of -almost every renowned individual familiar in every land and in every -household, and the attractions of every known country have been so -pictured by it that every intelligent child is familiar with them. It -has been said that process-engraving has supplanted wood-engraving. -This is not so. How many newspapers were illustrated before -process-engraving was made available? How many works of the old masters -and gems of the old museums abroad were made familiar to the lovers -of pictures everywhere, by wood-engraving? Instead of coming into the -arts to take the place of another, photo-engraving has made a place for -itself and a market for itself. Moreover, it is refining and educating -the masses by creating a love for art, where before its advent, there -was very little feeling for the beautiful. Its accomplishments have -been marvellous, and yet they have hardly begun. The good photography -has done in bringing the wood-engraver up to his duty in following the -artist in every line and light and shade, it will augment by teaching -him how to secure the loveliest effects of nature. It will make way for -more wood-engraving as well as for more process-pictures if you choose -to call them such. - - - - -|119| - -PART III. - -PHOTO-ENGRAVING ON COPPER. - - -CHAPTER I. - -SUBJECTS IN LINE. - -In printing from copper plates, the ink, instead of being spread on -the surface of the plate by means of a flexible roller as in ordinary -type printing, is smeared over the previously warmed plate and thereby -forced into the deep parts of the plate. Then, after the surface is -polished, the paper picks out the ink from these cavities and so forms -the picture. Therefore, instead of using a negative for producing the -resist, a transparency is required; and for the production of subjects -in line, the transparency must fulfil all the conditions laid down as -required in a negative for the production of prints for zinc etching -and for photo-litho. transfers, and must be from a subject in line or -in stipple. - -The negative is made the exact size required, by the wet collodion -process (the lens being used without the reversing mirror). This -negative is intensified by immersion in the bichloride of mercury -solution, and after well washing is blackened by the application -of ammonia, as directed in Part I. of this book, under the head of -photographic manipulation. - -The negative must be varnished, and the margin outside the actual -subject required to be shown in the copper plate, must be masked by -means of strips of tin-foil cut perfectly straight and laid in position -squarely and symmetrically. The object is to make this margin appear in -the transparency as perfectly clear glass. - -The masked negative is next placed in the carrier of the dark slide, -film up; then a couple of thicknesses of blotting paper about the -eighth of an inch square are laid on the extreme corners of the -negative. Upon these pieces of blotting paper a sensitive wet collodion -plate is placed face down. The little squares of blotting paper serve -to prevent the sensitive plate from touching the negative. |120| - -The camera, with the lens out of focus, should be pointed to a large -sheet of white paper; insert the dark slide, draw the shutter, uncap -the lens, and the light reflected from the white sheet through the -lens, through the negative upon the sensitive plate, will result, after -development, in a transparent positive of the negative. - -The time of exposure will, of course, vary and can only be found by -experiment. The operations of development, etc., are carried on as for -a negative. - -This method of making transparencies in the camera yields the best -possible results, as the rays of light are projected by the lens -perfectly parallel, and the resulting picture is far crisper than it is -possible to obtain by exposing in the ordinary manner. - -If the negative to be reproduced is already made, and is larger than -required, mask the margin by means of the tin-foil, place it in the -holder of an enlarging camera, film towards the lens if the negative -was made without a mirror; but if the mirror was used and the negative -is a reversed one, the film must be placed away from the lens. - -The camera is now adjusted so as to get the image the size required, -then a sensitive wet collodion plate is used to receive that image and -produce the transparency. - -The transparency for printing upon a copper plate must, when laid upon -a piece of white paper, allow every detail, however minute, to be -perfectly distinct by reflected light. If this is not so it will be -impossible to get a good engraving on the copper plate. - -The transparency being secured, a plate of highly polished copper -is cleaned with a little fine whiting and alcohol, then flooded -with water. Take care that all grease has been removed (which will -be detected by the water running in streaks); next wipe the plate -carefully with a clean, soft cloth, and place it in the jaws of the -whirler mentioned in the chapter on the apparatus for zinc printing. In -the dark-room coat the copper plate with prepared bitumen (see chapter -on engraving on zinc in half-tone), and set the whirler in motion. When -the film of bitumen is dry, place it in contact with the transparency -in a printing frame, and expose it to the light (sunlight, if possible). - -The time of exposure will depend very greatly upon the time of year and -day, but, in direct sunlight, ten to fifteen minutes will be about the -time. - -After exposure, the copper plate is removed from the frame, and placed -in a dish containing turpentine. Keep it rocking until the image is -developed by the unaltered bitumen being washed away, then remove the -plate from the dish, |121| and wash it well under the tap. When quite -dry, coat the back and edges of the copper with ordinary black varnish -laid on with a camel’s-hair brush, so as to prevent the mordant to be -used from attacking the back. - -Alterations and additions may now be made by means of transfer ink -thinned with turpentine, applied by a sable brush, or by means of an -etching needle or scraper, remembering that the etching needle or -scraper will make a black line and the transfer ink will cause a white -mark, or exactly the reverse of a type block. The plate is now ready -for etching in a - - Saturated solution of Perchloride of Iron 2 ounces. - Water 10 ounces. - -Use a porcelain dish for the solution. Immerse the plate, and keep it -rocking for about ten or fifteen minutes, then remove it, and wash -it under the tap, rubbing it gently with cotton-wool. After drying -it, warm it slightly, then roll up with a glazed leather roller, or a -smooth India-rubber roller charged with the hard ink used during the -clearing-up of the zinc block, viz.: - - Beeswax 1/2 ounce. - Resin 1 ounce. - Shoemaker’s Wax 1 ounce. - Litho-printing Ink, black 2 ounces. - -Melt together. When cool, mix with turpentine to the consistency of -soft soap. - -The roller is charged with this ink, and the plate warmed and rolled -up, so as to close up the high lights and half tones, leaving only the -deepest portions bare. Immerse in the etching fluid again for about -three minutes, rocking during the immersion, and finally wash the plate. - -Next remove the resist of bitumen, by means of turpentine, and take -proofs in the press. If deeper etching is required, proceed as before. - -The following is equally satisfactory, and a little quicker: - - Fuming Muriatic Acid (sp. gr. 1.190) 10 parts. - Water 70 parts. - -To this is added a boiling solution of - - Chlorate of Potash 2 parts. - Water 20 parts. - -This is diluted for use by adding 1 part to from 100 to 400 parts of -water. - -The time of immersion in either of these mordants is ruled by the -temperature of the room and of the liquids used. One or two careful -trials will soon give the desired information. - - -|122| - -CHAPTER II. - -HALF-TONE INTAGLIOS. - -We now come to quite a different class of work, namely, the production -of half-tone intaglio plates. They may be produced in many ways, each -way giving results quite unlike the others. - -The first process is based on the half-tone method given for -typographic blocks, modified to suit intaglio. - -In this, as in fact with ALL methods, we must first of all produce -a satisfactory transparency. That is best done by reproducing in an -enlarging camera. - -Place the negative, with the subject masked with tin-foil, in the -window, then focus upon the ground-glass screen of the camera the -requisite size; then prepare a wet collodion plate, and, having fixed a -grained screen* in front of the carrier, put the plate in its place, -then expose to the light and develop as directed for wet collodion -pictures; the result, however, will be a positive and not a negative, -and instead of the grain being interspersed through the high lights, -the shadows will be grained. - - * The grained screen is a copy from a proof from a fine ruled - copper plate. See Chapter on “Half-tone Blocks on Zinc.” - -The transparency must be made in this manner—_i. e._, from an ordinary -negative with a screen in front of the sensitive plate, so that the -shadows and half tones are grained or broken up. This would not be -the case if the transparency was made from a negative grained for -the production of a type block, as in such a negative the blacks are -represented solid and the lights and half-tones grained should be made -on large sized plates. - -The transparency made must fulfil all the conditions necessary for the -production of type blocks—_i. e._, the film must be perfectly free from -veil or fog; it may be varnished or not. - -The mark put upon the negative from which the transparency is made, -will cause the edges of the transparency to be quite clear. Coat a -clean piece of polished copper with the bitumen solution, using the -whirler as before; then |123| place the transparency in the printing -frame, film up, and place the bitumen coated copper plate in position, -so that the image is quite in the centre of the plate: fasten the -printing frame and expose to the light. - -The exposure will, of course, vary according to the strength of the -light, and should always, if possible, be made either in direct -sunlight or by electric arc light. - -The development is effected by immersion in turpentine, and with the -washing and drying, has already been described. - -The image on the copper plate being satisfactory, it may be retouched, -if necessary, then immersed in either of the etching fluids described -in the last chapter. - -Rebiting, if necessary, may be done after rolling up with the resist -ink there given, but care must be taken in this rebiting to guard -against interfering with the grain of the plate. - - -|124| - -CHAPTER III. - -HALF-TONE INTAGLIOS—(_Continued_). - -The next process under consideration is that in which the grain is -given to the copper plate by dusting it with fine powder of resin -(colophony) or of asphalt. To do this a dusting box is required, which -may be an ordinary aqua-tint box hung on centres for the purpose of -revolving it when desired to cover large plates with the powder. The -following figure will illustrate a box suitable for small work. - -[Illustration: Fig. 15.] - -The box should be eighteen inches high, twelve inches wide, and eight -inches deep; it may be made of cardboard with the inside quite smooth. -It should be closed all around except at A, where there is a small door -four inches high; the bottom of the box is either studded with small -nails or some coarse wire netting is stretched across, upon which the -copper plates can rest, as near level as possible. To use this box, -four ounces of resin or asphalt are powdered in a mortar until quite -fine. The powder is placed inside the box, and the door closed; the box -is now vigorously shaken, then placed on the table, the door opened, -and a copper plate (previously cleaned and polished) is at once placed -face up on the nails or wire netting. By the time the door is opened -and the copper plate or plates are in position, the coarser particles -of the resin will have subsided, leaving only the fine dust floating in -the interior of the box; now close the door, and leave the copper plate -within until it is judged that it is powdered sufficiently, which, of -course, will be a matter for the operator to find out by practice. - -When the plate has been sufficiently powdered, it is carefully -withdrawn and placed upon a hot iron plate and allowed to remain there -until the resinous |125| powder is just sufficiently melted to adhere -to the copper plate, preserving as much as possible the separate -existence of each atom of dust. Take care to stop the action of the -heat before the resin is melted completely and made to run together and -form a smooth surface. - -The heat having acted long enough, carefully withdraw the prepared -copper from the hot plate and allow it to cool. Any desired quantity of -these plates may be prepared and stored away for future use. When they -are required the grain may be selected to suit each picture, as the -operator can prepare at will (after practice) either a coarse or a fine -grained ground. - -Instead of using a hot plate the resin may be melted over a gas flame, -but the hot plate will be found the best. - -There is another method of laying this aquatint ground that is simple -and novel, viz., by using the air brush. Those who are in possession of -this instrument need no further instructions than to be reminded that -ordinary bitumen dissolved in benzole, or a resinous-spirit varnish, -is placed in the color reservoir, and then the brush will coat the -clean copper plate with an aquatint as fine or as coarse as required, -according to the distance between the plate and the “brush.” Another -advantage with this method of laying the ground is, the ground need not -be even, as in the dusting method, but the artist may lay the ground -coarse in some places and fine in others, _verb sap_. - -The next step in this process will be to get a transparency of the -subject. This may be made by any known process (at last, some one says -we are getting away from the wet collodion) so long as it is clean, -vigorous, and free from fog. - -The transparency being at hand, that portion of it required to be -transferred to the copper plate is carefully surrounded by a mask of -tinfoil, or of non-actinic paper, which will serve as a safe edge to -the carbon tissue to be used in making the negative resist, as well as -to keep the margin of the plate free from extraneous picture. - -This done, a piece of sensitive carbon tissue, a little smaller than -the copper plate, which has been previously sensitized with bichromate -of potash and dried, is placed upon the masked transparency and exposed -to light until sufficiently printed; the tissue is then removed from -the printing frame and placed in a dish of clean cold water; then one -of the copper plates with aquatinted ground is also placed in the -water, and the face of the tissue and the copper plate are brought in -contact. After adjusting the tissue on the copper |126| plate, the two -are withdrawn from the water, laid upon a bench, and a squeegee passed -over the back of the tissue. Thus the driving away of the water from -between the two surfaces will cause the tissue to adhere to the copper -plate. - -Now let the plate stand a few minutes, then immerse it in a dish of -warm water at about 90° F. As soon as the tissue compound is melted, -lift away the paper backing and throw it aside, then gently lave the -copper plate with the warm water until all the soluble pigmented -gelatine is dissolved; after that wash it under the tap, and place it -in a strong solution of alum for fifteen minutes, and again wash and -allow to dry. - -When the gelatine image on the copper plate is quite dry, the margin -outside the picture is coated with bitumen or spirit varnish, then the -plate is placed in the etching bath of perchloride of iron (see page -121), in which it is allowed to remain until the high lights under -the thickest portions of the gelatine image just change color; then -remove it and wash it under the tap; next clean off the resist image, -and after drying and cleaning up, try a proof. If necessary, ink up as -directed in Chapter I., page 121, and rebite. - -To succeed with this process it is only requisite to have a well-laid -ground, a good, vigorous transparency, and the carbon tissue in good -working order. - - * * * * * - -N. B.—In order not to confuse the above directions by interpolating the -working details of carbon printing, these will be given in a chapter -further on, together with formulæ for making suitable tissue. - - -|127| - -CHAPTER IV. - -HALF-TONE INTAGLIOS. ELECTROTYPING METHODS. - -The preceding methods of obtaining intaglio plates have been by the -etching process. We now try another method whereby the printing plate -is obtained by depositing a film of copper upon the photograph, and -from this copper electrotype the prints are to be made. - -There are many ways of proceeding to make these copper intaglios, the -grain being obtained in many ways, but the foundation is the same in -all, and consists of incorporating bichromated gelatine with grit of -such a nature as to cause the image to be rough instead of smooth, or -else the roughness is given to an ordinary or modified so-called carbon -image developed upon a silvered copper plate. - -The silvered copper plates upon which the gelatine images are to be -developed are prepared by dipping clean polished plates in a solution -of cyanide of silver, made by adding cyanide of potassium solution -to a solution of nitrate of silver until there is a slight permanent -precipitate. The copper plate remains in this for three or four -minutes; it is then removed, washed under the tap, and dried. - -The gelatine tissue compound is had by first of all making a jelly of - - Gelatine (soft) 8 ounces. - Sugar 5 ounces. - Water 25 ounces. - -Soak the gelatine until soft, then melt it at as low a temperature as -possible, add the sugar and churn all for fifteen minutes; then add to -one-half of the jelly one ounce of finely powdered graphite, and to the -other half one ounce of a coarser powdered graphite. Churn these well -together. - -Paper is coated with the above mixtures, floating it first upon that -containing the coarser graphite, then after drying, coat again by -floating the paper upon the gelatine containing the fine graphite, and -again drying. - -The paper is then sensitized by being immersed in a three per cent. -solution of bichromate of potash. Dry it in the dark. After exposure -to light under |128| a _negative_, it is developed upon the silvered -copper plate, after which the electro is made. - -Another plan is to expose a piece of ordinary carbon tissue under a -negative in the usual manner, then develop it upon the silvered copper -plate, and sift over the wet gelatine image some finely powdered glass, -sand, or emery which has been previously soaked in paraffine. The -gelatine is then allowed to dry, when the grit is brushed away, leaving -the gelatine image all marked and pitted. This pitted image is then -black-leaded, and the electrotype is taken from it. - -Another method is to place the newly developed carbon print on the -copper plate, inside the aqua-tint box, Chapter III. (having previously -shaken up the powder); when it is well dusted over, allow it to dry, -and then remove the powder by dissolving it out with either alcohol, -turpentine, or benzole, after which the electrotype is made. - - - - -|129| - -PART IV. - -PHOTO-LITHOGRAPHY IN LINE. - - -CHAPTER I. - -This process is for making photographic reproductions of a subject in -black lines on a white ground, half-tones and shadings being indicated -by hatching, or stipple, but no washes of color are permissible. The -object sought for from such a subject is to produce a transfer which -can be laid down upon stone or zinc, and proofs printed therefrom in -the ordinary lithographic press or machine. - -To gain this end there are three methods: the first, by printing upon -paper prepared with bichromated gelatine, the lines of which, after -exposure to light under a direct negative (_i.e._, a negative taken -without a mirror behind the lens), will retain ink, whilst the gelatine -protected from light absorbs water, and rejects the ink. The result is -a replica of the original in fatty ink, and may be transferred to stone -or zinc, and printed from by the usual lithographic method. - -In the second method, a print is made upon zinc from a reversed -negative (in the same manner as directed in Chapter V., Part I.) in -bichromated albumen, which is rolled up in transfer ink, and from -that a transfer is pulled on Scotch transfer paper, which may then be -transferred to stone or zinc, and printed from at a litho. press or -machine. - -In the third, and by far the best method, the print is made from a -reversed negative on zinc, in bitumen, as directed in Chapter V., Part -I., then rolled up in transfer ink, the transfer pulled on Scotch -transfer paper, then transferred to stone or zinc, and printed from at -a litho. press or machine. - -The defects inherent to the first method are, first of all, in the -preparation of the gelatine paper; this is tedious and messy. Then -there is always danger of breaking the lines in transferring, and also -the difficulty of working exactly to scale. |130| - -The second method is quick, easy, and simple, the only drawback being a -tendency of the lines to thicken. With this and the third method there -is no difficulty in getting absolute scale. - -The third method is perfect, and presents no drawbacks. - -The two latter methods having been amply explained in Part I., it will -not be necessary to redescribe them, except to explain that when the -print is made on the zinc in albumen, it is gummed in, fanned dry, then -damped off with a wet sponge, followed by a damp cloth, rolled up with -transfer ink, and the transfer pulled upon good Scotch transfer paper. - -The same remarks apply to bitumen prints. - -For a transfer printed in bitumen, the image is developed in -turpentine, and when this is completed, wash the plate thoroughly under -the tap, then immerse it in the graining bath (Part I., Chapter I., -page 24), and keep the tray rocking for a few minutes; the effect of -this will be to destroy the polished surface of the metal, substituting -a pearly matt surface, which will show up the picture properly, and -allow the operator to judge whether any of the fine details are -wanting; if there are, it will be necessary, if the details are -dissolved out, to repolish the zinc, first with pumice-stone, then with -snake-stone, then with pumice powder, finishing with fine rouge; then -coat with bitumen, whirl, and again expose to light, giving this time, -longer exposure under the negative. - -But if the fine details are buried in undissolved bitumen, a further -immersion in the turpentine bath will soon clear them; then again wash -under the tap, immerse in the graining bath, again wash, then, with a -sheet of clean blotting paper, remove the surplus water, and allow the -surface to dry in a cold current; but beware of using heat, as it has a -tendency to make the bitumen image refuse ink in rolling up. - -The zinc being dry, it is gummed in, fanned dry, then the gum is -washed off, and the image rolled up with a leather roller charged with -transfer ink. As soon as the bitumen has taken the transfer ink all -over, a transfer is pulled upon Scotch transfer paper, which in turn is -transferred to stone for printing from. - -In rolling up these prints upon zinc, care must be taken to keep the -surface (whether the image is in albumen or bitumen) properly damp. - -The preparation of paper transfers will be treated upon in the next -chapter. - -The negative from which these transfers are made, must have all the -characteristics of a good negative for printing on zinc for etched -blocks, viz., the lines |131| must be represented by clear glass, and -those portions of the negative representing the whites of the original, -must be as near opaque as possible. - -The subjects to which photo-lithography is applicable, are those that -are strictly in line, or stipple, or dots, or cross hatched, or chalk -drawings; in fact, any subject that may be done by lithography, or in -black and white; but no shading by color washes is permissible. - -Transferring to stone or zinc is done as follows: - -First of all, the transfer is trimmed to proper size; it is then placed -in a damping book, made by placing wet sheets of brown or good printing -paper alternately with dry sheets, then placing all under a weight for -a few hours, until the whole of the book is evenly damp; the trimmed -transfer is allowed to remain here until limp; it is then sponged on -the back with a very little of oxalic acid (half an ounce), water -eighty ounces; now lay the transfer carefully down on a perfectly clean -and polished stone, backing the transfer with a piece of smooth paper. -Having adjusted the pressure of the scraper on the stone, pull through -twice, then reverse the stone in the press, and pull through twice -more. Then remove the backing and lift the transfer from the stone, -when the whole of the ink should be upon the stone, leaving the paper -quite clean. Now, if the picture is quite satisfactory, wipe the stone -first with a wet sponge, then with a damp cloth, then gum in and allow -to dry, and, if possible, to stand with the gum on all night. - - -|132| - -CHAPTER II. - -PAPER TRANSFERS. - -Paper for photo-lithographic transfers may be made by coating bank post -paper or a good hand-made writing paper, with - - Gelatine (Nelson’s) 2 ounces. - Water 20 ounces. - -Put the above into a wide-mouthed bottle or jar, and allow the -gelatine to soak until soft; then place the vessel in a large saucepan -containing cold water, and set on a fire, or over a gas-burner, and -by the time the water in the saucepan is hot the gelatine will be -dissolved. Then add slowly (stirring the gelatine with a glass rod) one -drachm of a ten-grain solution of chrome alum. Now strain the gelatine -solution through fine muslin into a clean dish, standing it in a larger -dish containing hot water; float the bank post paper upon this solution -(taking care to avoid air-bubbles) for two minutes, then lift it off -slowly and hang it up to dry, pinning it by two corners to the edge of -a shelf. - -When dry, the operation is repeated, but this time the paper is hung -up to dry by the two opposite corners, so as to equalize the coat of -gelatine. - -When dry a second time, it must be floated for two minutes upon - - White of 5 eggs. - Water 13 ounces. - -(Shake up well, and filter into a cold dish.) - -Paper prepared as above will keep for any reasonable length of time. - -For use, it is drawn slowly through a solution composed of - - Bichromate of Potash 1-1/2 ounces. - Water 20 ounces. - Alcohol 5 ounces. - Liquor Ammonia 10 minims. - -This being done, the paper is again hung up to dry, this time in a dark -room. - -When dry, the paper should be laid face down, upon a polished litho. -stone, and be pulled through the press three or four times, so as to -get the surface as smooth as possible, and insure absolute contact. -|133| - -This must be done in a yellow light, or in a room lighted by gas or oil -light. - -The paper is now placed in contact with the negative, in a -printing-frame, and exposed to light; the exposure for such paper -should be from five to fifteen minutes. - -Note well that these paper transfers are printed from negatives taken -direct in the camera, without the intervention of the mirror, therefore -negatives suitable for printing paper transfers will not do for -printing upon zinc, or _vice versa._ - -The progress may be watched by undoing one side of the back of the -frame, and examining the image in the dark room; but in damp weather -this should not be done too often, as the paper may expand or contract, -and blur the image. - -The exposure to light under the negative being complete, the print is -removed from the frame in the dark room, and is next coated with a thin -film of ink as follows: - -A smooth litho. stone is carefully coated with a fatty ink by means of -a leather roller, extreme care being necessary to insure an even coat -of ink over the stone; this being attained, the exposed print is laid -face down (the room being lit by yellow light or gaslight) upon the -inked stone, then a piece of backing paper laid upon it, and pulled -through the press, with a good nip upon it; pull it through twice, -then reverse the stone on the press, and again pull through twice, -which will leave a fine, thin film of ink upon it. Now take the inked -print, and place it in a tray of clean, cold water, allow it to remain -therein for five minutes, then lay the print upon a piece of glass, -and rub it gently with a pad of cotton-wool—previously wetted in the -water. This will remove the ink from those portions of the paper that -were protected from the action of light by the opaque portions of the -negative, representing the whites of the original. - -The application of the pad of cotton-wool is continued until the whole -of the picture is cleared from superfluous ink, and the lines composing -the image are evenly coated with ink. The ink adheres only to those -portions of the paper which the light has acted upon, through the -negative. - -Now wash the transfer under the tap, then hang it up to dry. When dry -it is ready for transferring to stone or zinc. - -To transfer to stone or zinc, place the transfer first of all in the -damping book, and when limp place it upon a clean, cold, polished -stone, and pull it through the press. |134| - -When transferred, the image is treated in exactly the same manner as an -ordinary transfer on stone or zinc. - -The enamelled double transfer paper sold for double transfer carbon -work may be used for photo-litho. transfers by floating it upon - - Albumen 5 ounces. - Water 20 ounces. - Saturated Solution of Bichromate of Potash 3 ounces. - Liquor Ammonia 10 drops. - -and then dried. - -Paper thus prepared must be kept in a dry air-tight case, and just -before using is laid face down upon a smooth litho. stone, and pulled -through the litho. press. After this, it is placed in contact with the -negative in the printing frame, and exposed to light until the details -are visible. Although the progress of the action of light can be seen, -the frame must not be opened too often, or the paper is apt to expand -and blur the image. After exposure the print is inked up, developed, -and treated exactly as explained above. - -The ink suitable for inking up the stone, previous to laying upon it -the exposed print, is composed of - - Best Chalk Litho. Printing Ink 3 parts. - Mutton Fat 1 part. - -Put the ink and fat into a small iron or earthenware pot, and place it -over a Bunsen burner, or a paraffine stove, or on the hot plate of a -kitchen stove (_but not over an open fire_); allow the heat to melt the -two ingredients, stir so as to incorporate them thoroughly; take great -care not to allow it to catch fire; if it does, at once extinguish the -flame, as the firing would be apt to spoil the ink. When thoroughly -melted and incorporated, pour into a tin, or pot, for use when cool; -the time occupied in making this ink will not exceed twenty minutes. -The mutton fat is obtained by dropping solid kidney suet (shredded) -into a pan of clean boiling water, then allowing to cool, when the fat -is taken off the surface of the water, freed from damp and stored for -use. - -Another formula for the preparation of paper, to be inked up, after -printing in the same manner as the above transfers, is to coat paper -twice with the following preparation, drying between each coat: -arrowroot, 1 ounce; wet this thoroughly with 5 ounces of cold water, -stirring well with a spatula, adding more cold water, if necessary, to -moisten the lot; then pour over it 20 ounces of boiling water, stirring -all the time; if, when the 20 ounces are added, |135| the arrowroot -has not thickened, add more boiling water until it does do so; now add -1/2 an ounce of powdered bichromate of potash and stir until dissolved; -then strain through muslin into a warm dish and float the paper upon it -whilst hot, and dry at a temperature of 70° F. - -If the bichromate of potash be omitted, the paper may be prepared -in quantity and stored away for future use, being made sensitive by -floating for five minutes upon - - Bichromate of Potash 1 ounce. - Water 25 ounces. - -Paper for either gelatine or arrowroot transfers, after keeping so long -after preparation as to be useless, should not be thrown away, but -should be again floated upon bichromated gelatine or arrowroot, and -after drying will give finer results than new paper. - -Prof. Husnik’s photo lithographic transfer paper is obtainable in -England and in America. He recommends the following chromate bath: - - Bichromate of Ammonium 1 ounce. - Water 15 ounces. - Alcohol 4 ounces. - Liquor Ammonia 1 ounce. - - Keep well corked in a dark place. - - -|136| - -CHAPTER III. - -PAPER TRANSFERS—(_Continued_). - -Prepare a solution of - - Gelatine 5 ounces. - Sugar 1 ounce. - Water 20 ounces. - -Soak the gelatine in the water (cold) until quite soft, then melt it by -the application of heat (nothing is better for this sort of work than a -_Bain Marie_, a domestic utensil with a porcelain pan enclosed in one -of tin); then add the sugar and stir well, continuing the application -of heat until a temperature of 150° F. has been reached; now strain -the gelatine through muslin, into a clean dish placed in a larger dish -containing boiling water, the heat from which will keep the solution of -gelatine in a properly liquid state during the operation of coating the -paper. - -The best for these transfers is a good hand-made writing paper, or good -bank-post. - -Cut the paper into suitable sizes, leaving a little extra margin at one -end, and float it upon the hot gelatine solution as above; be careful -in laying the paper upon the gelatine, that air bells are avoided; when -the sheet is laid upon the surface, raise it rapidly, and throw it at -once over a cylinder of cardboard or of wood, and at once commence -to revolve this cylinder rapidly, first in one direction, and as the -limit of the length of paper is reached, revolve it in the other, -which motion will alternately bring first one end uppermost and then -the other. By this means an even coating of gelatine upon the paper -is secured, which is not possible when the paper is hung up by clips -directly it is taken from the surface of the hot gelatine. The cylinder -is kept revolving until the gelatine has set, when it may be hung up to -dry upon clips, or laid face up, over a line upon a piece of cardboard; -during the operation of revolving the cylinder, any air bells formed in -the gelatine coating may be removed by blowing or pricking them. - -This, to my mind, is a most elegant method of coating small sheets (up -to thirty inches long) with a coat of gelatine, for which I willingly -give the |137| Royal Engineers the credit, it having been demonstrated -to me by Ex-sergeant Dalton, of that corps. - -Paper coated in this manner, when dry, is ready for sensitizing; but if -coated in the ordinary manner, it should, when dry, be coated a second -time and hung up to dry in the opposite way that it was the first time. - -Paper coated with gelatine solution as above, may be stocked, as the -coating does not deteriorate with time; but the operator must be -careful not to allow the solution of gelatine to get below 125° during -coating, else the surface will be sticky. The temperature of the drying -room must not exceed 70°, in fact, 60° will be best. - -Paper so coated is sensitized by immersion for three minutes in - - Bichromate of Potash 2 ounces. - Water 50 ounces. - -In hot weather this solution must be kept cool with ice. - -When the time of immersion has expired the paper is removed, and laid -face down upon a sheet of glass free from scratches—which sheet of -glass has been well polished with finely powdered talc (or French -chalk)—now squeegee the back of the paper vigorously, to remove the -superfluous solution and bring the surface of the paper into absolute -contact with the glass plate. The sheet of glass is now placed in a -rack, in the dark room, until the paper is quite dry, when it may -be readily stripped off the glass, and is ready for printing the -transfer. The operation of drying should be done in a current of air -at a temperature of about 60°, and the paper must be quite dry before -attempting to strip it from the glass. - -The exposure under the negative is the same as described in the -previous chapter. - -When sufficiently exposed, the print is removed from the frame in the -dark room, and at once immersed in cold water, where it is allowed -to stay for five minutes, when it is withdrawn and laid upon a piece -of plate glass, or a zinc plate, the face being uppermost; then the -loose end of the paper (provision for which must be made in cutting -the paper) is tucked under the plate, so as to hold the transfer in -position in the subsequent operations. - -Now take a glue roller (the same as used for inking up the albumen -image on zinc, described in Part I., Chapter IV.), and having spread -a little of the ink described in the last chapter (chalk, litho. ink, -and mutton fat) upon the slab, charge the roller carefully with a thin -coating of ink, and then, having |138| removed any moisture from the -face of the transfer with a soft sponge, apply the inked glue roller, -rolling one way only—_i.e._, from the body (presuming that the edge -of paper tucked under the slab is next the body of the operator); -continue rolling until the whole of the lines forming the picture are -coated with ink, and the whites quite clean and free from ink. If the -roller should get wet from water oozing from under the transfer, wipe -it with a damp cloth and then roll it a few times on the inking slab, -and continue rolling the transfer. Be careful that the portion of the -transfer representing the whites of the picture has absorbed its full -modicum of water before beginning to roll up, and also that there is -not too much ink upon the roller. When the transfer is successfully -inked up, it is hung up to dry, and when dry is trimmed to size, placed -in a damping book, and transferred to stone. - -The exposed transfer, after wetting, and being placed upon the plate -of glass, or zinc, may be developed in another way. First remove the -superfluous water from the surface with a soft damp sponge, then rub it -gently all over with a pad of cotton-wool dipped in a thin mixture of -ink thinned with turpentine and well mixed with a palette knife (this -ink should be a little thicker than ordinary copying ink); all the -image must be covered with the ink. The turpentine is then allowed to -evaporate, when by rolling with the glue roller from the body, the ink -will clear away from the whites, leaving the lines sharp and distinct. -Do not use too much pressure, else the ink may be removed from the -lines, in which case cover the whole picture with a fresh coat of the -thin ink, and again roll off. The subsequent operations are the same as -for the other paper transfers. - -The ink for this method is made by melting over a Bunsen burner, or -paraffine stove, - - Chalk Printing Ink 4 ounces. - Beeswax 1/2 ounce. - Stearine 1/2 ounce. - Resin 3/4 ounce. - -When these are melted and well stirred together, set the mixture on -fire and allow to burn for three minutes, then extinguish by putting -the cover on the pot or pan, then pour it into a tin. When cold it is -ready for use. - -In handling the sensitized gelatine paper for transfers, every care -must be exercised to keep the paper from being exposed to the action of -light, before and after exposure in the printing frame, else there will -be great difficulty in getting clean transfers. - - -|139| - -CHAPTER IV. - -TOOVEY’S NEGATIVE TRANSFER PROCESS. - -A good smooth paper is floated for five minutes upon finest picked - - Gum Arabic 5 ounces. - Water 15 ounces. - Bichromate of Potash 1 ounce. - -This is dried in the dark, then exposed to light in a printing frame -under a direct negative. It is then laid, face down, upon a polished -zinc or stone, if a line subject, or on a grained zinc or stone, if a -half-tone subject; upon the back of the print several sheets of damp -paper are laid, and then the whole is subjected to very heavy pressure -in a hydraulic press, so that the water in the damp paper may be forced -through the print and dissolve the gum in the unexposed parts of the -sensitive gum coating (which is still soluble). The dissolved gum -attaches itself to the stone, whilst the exposed parts being rendered -insoluble by the action of light, the damp has no effect upon it, and -the stone is protected in those parts. - -When the stone has been under pressure for a sufficient length of time, -to allow the small traces of gum in the deepest shadows to attach -themselves to the stone, the pressure is removed, the stone withdrawn, -and the paper carrying the photographic print is carefully lifted up, -leaving the bare negative image on a gummed ground. The stone is well -dried, and covered all over with a greasy ink applied by a roller or -otherwise. The ink is thus brought into contact with all parts of the -stone or zinc unprotected by the gum. - -The image is then washed out with turpentine, and the gum removed by a -damp sponge, after which the stone or zinc is rolled up in the ordinary -manner with a leather roller, and is printed from in the ordinary -manner. - -Of course, it will not be expected that the best results are obtainable -by so simple a process. Perhaps in no other branch of work does an -outlay of thought and time “pay” so well as in the practice of these -interesting photo-printing methods. - - -|140| - -CHAPTER V. - -PHOTO-LITHO. TRANSFERS. - - -TO DEVELOP PHOTO-LITHO. TRANSFERS. - -_To develop photo-litho. transfers on paper_ there are two methods. The -first and oldest is, after exposure, to coat a smooth litho. stone with -a thin layer of transfer ink, by means of a leather roller, then to lay -the exposed print face down upon this inked stone, and pull it through -the press. Of course, this must be done in a dark room, or by gas or -oil light, as daylight would spoil the transfer. - -Now the inked and exposed transfer is placed in water at 80° F., and -allowed to remain for three or four minutes, when it is taken from the -water and placed upon a plate of glass, and the superfluous ink is -removed by means of a sponge dipped in the hot water. If the negative -has been sufficiently opaque, and the exposure right, the image will -quickly develop, the lines retaining the ink, while that upon the -whites will come away. - -Hot water is used where the coating is of gelatine only; if gum arabic, -or albumen has been used, then, after inking up on the stone, the -transfer must be developed in cold water, and cotton-wool used to -remove the ink from the whites, rubbing very carefully with very little -pressure. - -Paper prepared with a thick coat of gelatine may be developed in -another way; after removing it from the printing-frame, the transfer -is inked up on the stone, then placed in a dish of cold water and left -there for five or ten minutes; then removed and placed upon a thick -glass slab, the end tucked under so that when placed on the bench -the slab will press the paper and keep it in position. Now, with a -sheet of clean blotting-paper, remove the water from the transfer, -using pressure with the hands from the end tucked under the slab; -then, with a glue roller, roll from the tucked under end until the -image is developed. Instead of inking the transfer up when dry, the -transfer may be placed in the cold water directly it is taken from -the printing-frame, and allowed to remain for ten or fifteen minutes, -during which time the image will swell, by the whites absorbing water. -Now place upon the glass slab (one end being tucked under), and remove -the superfluous water first with a |141| sponge, then with a damp -cloth; now dip a sponge in transfer ink thinned to the consistency of -cream by turpentine, and dab all over the damp transfer, then allow -it to stand until the turpentine has evaporated. Next take the glue -roller and roll the transfer until the whites are clear; only roll one -way—_i.e._, from the end tucked under the slab. - -The transfers being developed, they are rinsed with clean water, -and hung up to dry in a current of cool air. If dried at too high a -temperature, the transfers will be inferior, and difficult to handle. - -[Illustration: Fig. 16.] - -Instead of using a slab of glass, and tucking the end of the transfer -underneath, a proper developing-board may be used as follows: A is a -clamped board 18 inches by 12 inches, by 1 inch thick; B is another 4 -inches by 12 inches; these are hinged together at C, the hinges being -let into the boards underneath. Now, if the transfer be laid upon the -board A, the end placed in the aperture C, then the pressure of the -roller will cause the piece B to clamp the paper quite tight. - -A few little differences in manipulation are required by the various -transfer papers found on sale in the market. For this reason I add the -instructions given by Prof. Husnik for his transfer paper. - -_Making the paper sensitive._—Pour the solution in a shallow glass or -porcelain dish (such as photographers use), take hold of the paper -on two opposite ends, dip one end (prepared side _upward_) in the -solution, and draw the paper through so that the whole surface is -covered evenly with the solution; drain off and hang it up for drying -in a _dark_ room. Pins may be used for this purpose. Never _reverse_ -the paper in hanging it up. Wet only as much of the paper as you intend -using at every one occasion. In hot summer weather the so prepared -paper must be used within a few hours. In cold and damp weather it -keeps good for three days. After the paper has passed through the bath -the _prepared side_ of it must not be brought in contact with anything -whatever, as the least touch will create a spot in the picture. For -pouring back the solution into the bottle use a glass funnel. It is -very advisable to run the sensitive |142| paper on a polished stone or -metal plate through a lithograph press to give a smooth surface. - -_The development_ of the picture can begin after the mentioned time and -is to be accomplished with a fine, solid, and very soft sponge, rubbing -in circle-form with it over all parts of the picture until all the ink -is washed out of the lights, the lines becoming clear and distinct -and the shade properly open. The water must be changed several times, -passing always with the sponge delicately over all parts of the picture -to remove all uncleanliness from it. But never go over the picture -with a dry sponge. After washing the picture clean it is laid between -damp printing paper and slightly pressed with the hands to remove -the superfluous water. Was the exposure of the picture too _long_ it -will be very difficult, yea, impossible to develop it. Too _short_ an -exposure will lose the fine lines. The proper time of exposure will -easily be learned. - -_For very fine reproductions_ the paper should be dried and inked in -the following manner: - -Take a pane of glass, coat it with a fatty substance, as tallow or wax -dissolved in benzine; wipe the glass clean, so as to leave only a trace -of fat on; lay the paper in the solution about one minute, drain off -and then lay the paper face down on the glass, removing all air bubbles -by rubbing over the back with a rubber straight edge, or better, a -squeegee. When dry, the paper will leave the glass easily and will have -a glass-like surface. - -_The inking._—Take common lithographic transfer ink, mix with it -one-fourth part of the photo-lithographic ink and coat a smooth stone -with an even tint, taking care not to make it too thick (a smooth -lithograph or composition roller will answer). Lay the printed picture -face down and run it through the press with a good pressure; the -picture will be covered with an even tint, showing the picture through -it. - -The development is the same as above described. This later method gives -excellent results. - -_Transferring._—When all the water is removed from the picture, and -while damp, lay it on the stone and make the transfer with the same -care as other transfers are made, starting with a very light pressure; -and if the paper sticks to the stone, increase the pressure. It is -advisable to wash the stone with pure turpentine, and dry it before -transferring. - - - - -|143| - -PART V. - -PHOTO-LITHOGRAPHY IN HALF-TONE. - - -CHAPTER I. - -This process, like photo-engraving, has been the subject of many -applications to the Patent Office, but the first notable progress was -made by Messrs. Bullock, in 1865. They seem to have gone into the -subject thoroughly, as the elaborate and practical specifications -prove, but although the patentees issued some fine specimens of their -work, and advertised the sale of prepared paper, nothing came of it. - -Messrs. Bullock’s method comprises the printing from grained stone -tile, or a stone upon which has been laid a transfer, from a stipple -plate, or a plate engraved in lines or dots—upon sensitive transfer -paper in stiff ink. - -The sensitive paper, with such imprint upon it, is exposed to light -under a negative, the specks of ink forming a medium for breaking up -the half-tones. - -Suitable grain may be obtained from machine stippled plates, as well as -from grained stone. - -Half-tone photo-lithography may also be made by making, from a proof -pulled from a machine stipple, or a ruled plate, or a grained stone, a -wet, collodion negative, which, being stripped from its glass support -(by any of the means mentioned in the chapter on stripped films) is -placed between the ordinary half-tone negative and the sensitive -surface—zinc, coated with bichromated albumen, or with bitumen, or -either of the transfer papers treated of in Part IV.—the result will be -a grained transfer. - -Grained zinc, coated with bichromated albumen, or with bitumen, and -exposed under a very thin half-tone negative, will also yield transfers -suitable for a good many subjects, but the most successful methods are -modifications of the collographic printing processes. - -Transfers made by any of the methods mentioned in the following -chapters may be transferred to polished zinc, and then etched in -relief, as directed in Part I. - - -|144| - -CHAPTER II. - -INK PHOTOS. - -The various methods named in the last chapter for breaking up and -transferring to stone the delicate half tints of a photograph from -nature, are in a great measure rather crude and do not give the fine -results yielded by the following modification of the collotype process, -nor are they so certain and simple in their working. - -The production of ink photos is as follows: A plate of flat copper is -grained by means of graining sand and a piece of litho. stone, the -sand being put through a fine sieve (about 120 holes to the inch). The -copper plate being, first of all, well polished and without scratches, -is placed upon a flat board, the graining sand is then sieved over it, -and moistened, then with a light, firm motion of the wrist, the whole -of the surface is evenly ground. The operation of graining is very -difficult to describe, except to say that the stone muller is shuffled -all over the plate until the polished surface of the copper is replaced -by an even matt. Renew the sand when necessary. Do not try to get -through the operation rapidly by taking large circles, else scratches -are sure to result. - -The copper plate being grained, it is well washed, back and front, so -as to free it from all grit, then coated whilst wet with - - Stale Beer (not lager) 5 ounces. - Water 5 ounces. - Silicate of Soda (syrupy) 1 ounce. - Tannin 1 grain. - -Shake well, then filter; coat the plate twice and stand it on a rack to -drain and dry. When dry swill the plate under the tap and again dry. -These plates may be prepared in advance, as they improve by keeping. - -Now prepare the following solutions: - - Best Cologne Glue 1 ounce. - Water 10 ounces. - -When dissolved add - - Bichromate of Potash, in powder 30 grains. |145| - -Stir until dissolved, then add - - Nitrate of Silver 30 grains. - Dissolved in Water 1 ounce. - -Stir well, then add - - Chloride of Calcium (crystals) 10 grains. - Dissolved in Water 1 ounce. - -Stir up well, then add - - Acetic Acid 1/2 drachm. - -Again stir. - -Warm the coated copper plates by letting them lie upon the slab of -the drying oven. The drying oven is described in the chapter on -collotype printing, and for this process the slab should be at about a -temperature of 150° F. Now strain the above mixture through muslin into -an invalid’s cup with a long spout, and holding the warm copper plate -horizontally on the palm of the left hand, proceed to pour over it as -much of the gelatine mixture as will well cover it. Do not have a very -thick film, else the grain will be too coarse; nor too thin, or there -will be no grain at all. Practice will soon enable the operator to -apportion the proper quantity to each plate. As a rough estimate, about -one fluidounce of the mixture for a plate 12 × 10 will be required. - -The plate being coated, it is placed on the slab of the drying oven and -left there until dry. That will take from one and a half to two hours. -The exact temperature at which to dry these films cannot be arbitrarily -stated, as so much will depend upon the picture which is to be printed; -therefore, a few experiments will be necessary before settling down -to an exact form of working. A good plan that answers admirably is to -raise the water in the tank of the drying oven to boiling point before -coating the plate, then coat the plate, lay it on the slab, let the -water in the tank boil for a few minutes then turn out the gas and let -the plate dry. - -The plate being dry it is exposed under a good ordinary (reversed) -negative until the whole of the details are well out. Time the exposure -by means of an actinometer. - -After exposure under the negative, remove the plate from the printing -frame and in the dark room cover it with litho. transfer ink by means -of a leather roller, taking care that the whole of the surface is well -coated with the ink. Now place it in clean cold water for three or four -hours, then with a soft |146| sponge remove as much of the ink as will -come away. This operation will take time, as every care must be had not -to scratch the film. - -Now rinse the plate under the tap and allow it to dry. - -When dry soak it in cold water for half an hour, then place it on the -press (an ordinary letter press), and with a sponge and soft cloth -remove the superfluous water from the film; then roll up with a leather -roller charged with litho. transfer ink as thick as can be worked. -When the image is properly inked up pull a transfer upon good Scotch -transfer paper. - -Perhaps the first two or three pulls will not be satisfactory; -therefore, it will be best to pull a few before using the transfer -paper, damping and wiping between each pull just in the same way that -is done in printing from a lithographic stone. - -A good transfer being obtained, it should be given to a lithographer -to put it down upon a grained stone, an operation which requires great -skill and experience. The student’s interest will be best consulted by -not attempting to give a description of how to transfer to a grained -stone. - -Another formula for a sensitive coating for the copper plate is - - Gelatine 1 ounce. - Water 6 ounces. - -Soak the gelatine till soft; then melt, and add one drachm of -bichromate of potash in powder; stir until dissolved; add twenty grains -of good fresh dextrine and let the mixture cool to about 120° F.; -then add one drachm of liquor ammonia and six ounces of alcohol. The -subsequent operation of coating, etc., is the same as above. - - -|147| - -CHAPTER III. - -HUSBAND’S PAPYROTINT PROCESS. - -This is a process for the production of photo-lithography in half-tone, -direct from the negative, without the intervention of a collotype plate -from which to pull the transfer, and is a distinct step in advance. - -This process has been named papyrotint, being a modification of Captain -Abney’s improved method of photo-lithography, named papyrotype. It is -specially adapted to the reproduction of subjects in half-tone, such -as architectural drawings in monochrome, or subjects from nature, and -it is inexpensive. Its advantages over other methods of half-tone -photo-lithography are, that a transfer can be taken in greasy ink, for -transfer to stone or zinc _direct_ from any negative, however large, -without the aid of a medium, the grain or reticulation being obtained -simply by a chemical change. The transfer paper being in direct contact -with the negative, the resulting prints are sharper than by those -processes where interposed media are used; whilst the same negative -will answer either for a silver print, platinotype, or a transfer -for zinc or stone. The advantage of being able to use a non-reversed -negative is very great, now that gelatine plates have so largely -superseded those made with collodion. - -The method of manipulation is as follows: Any good surface paper is -floated twice on a bath composed of - - Gelatine (Nelson’s Flake) 8 ounces. - Glycerine 1-1/2 ounces. - Chloride of Sodium (Common Salt) 2 ounces. - Water 50 ounces. - -Great care should be taken that the solution is not overheated, and -that the paper is coated without bubbles. It is then dried in a -temperature of 60° F. The paper will take about ten hours to dry, and -in this state will keep for years. When required for use, it should be -sensitized by floating on, or immersing in, a bath of - - Bichromate of Potash 1 ounce. - Chloride of Sodium 1/2 ounce. - Ferridcyanide of Potassium 100 grains. - Water 30 ounces. |148| - -This need not be done in a dark-room, as the solution is not sensitive -to light. - -The paper, after sensitizing, is dried in a temperature of 70°, and in -a dark room. When dry, it is exposed under any half-tone negative, in -the ordinary printing frame. It is preferable to print in sunlight, -and, for negatives of medium density, an exposure of three minutes is -required; but the exposure will vary according to the density of the -negative. The correct time of exposure can best be judged by looking at -the print in the frame. When the image appears on the transfer paper -of a dark fawn color, on a yellow ground, the transfer is sufficiently -printed. It is put into a bath of cold water for about ten minutes, -until the soluble gelatine has taken up its full quantity of water; -then taken out, placed upon a flat piece of stone, glass, or zinc -plate, and the surface dried with blotting paper. - -The action of the light has been to render the parts to which it has -penetrated through the negative partly insoluble, and at the same time -granulated. A hard transfer ink is now used, composed of - - White Virgin Wax 1/2 ounce. - Stearine 1/2 ounce. - Common Resin 1/2 ounce. - -These are melted together in a crucible over a small gas-jet, and to -them are added four ounces of chalk printing ink, and the mixture -reduced to the consistency of cream with spirits of turpentine. A -soft sponge is saturated with this mixture and rubbed gently over -the exposed paper (in this stage the nature of the grain can be best -seen). An ordinary letter-press roller, charged with a little ink from -the inking slab, is then passed over the transfer, causing the ink to -adhere firmly to the parts affected by the light, and removing it from -the parts unacted upon. It will be found that with practice, rolling -slowly and carefully as a letter-press printer would his form, the ink -will be removed by the roller according to the action that has taken -place by light, leaving the shadows fully charged with ink, and the -high lights almost clear, the result being a grained transfer in greasy -ink. The transfer is next put into a weak bath of tannin and bichromate -of potash for a few minutes, and when taken out the surplus solution -should be carefully dried off between clean sheets of blotting paper. -The transfer is hung up to dry, and when thoroughly dry, the whole of -the still sensitive surface should be exposed to light for about two -minutes. A weak solution of oxalic acid should be used for damping the -|149| transfer (about 1 in 100), and this should be applied to the -back of the transfer with a soft sponge. After it has been damped about -four times, it should be carefully put between clean sheets of blotting -paper, and the surplus moisture removed. A cold polished stone is then -set on the press, and when everything is ready the transfer is placed -on the stone and pulled through twice. The stone or scraper is then -reversed, and the transfer is again twice pulled through. A moderate -pressure and a hard backing sheet should be used, care being taken not -to increase the pressure after the first pull through. The transfer is -taken from the stone without damping, when it will be found that the -ink has left the paper clean. Gum up the stone in the usual way, but, -if possible, let the transfer remain a few hours before rolling up. Do -not wash it out with turpentine, and use middle varnish to thin down -the ink. - -It should have been mentioned that varying degrees of fineness of grain -can be given to the transfer by adding a little more ferridcyanide of -potassium in the sensitizing solution, and drying the transfer paper -at a higher temperature, or by heating the paper a little before -exposure, or by adding a little hot water to the cold water bath, after -the transfer has been fully exposed; the higher the temperature of the -water, the coarser the grain will be. The finer grain is best suited to -negatives from Nature, when a considerable amount of detail has to be -shown. - -The coarse grain is best for subjects in monochrome, or large negatives -from Nature, of architecture, etc., where the detail is not so small. -Even from the finer grain, several hundred copies can be pulled, as -many as 1200 having been pulled from a single transfer. It would have -produced a great many more if required. - - - - -|151| - -PART VI. - -COLLOGRAPHIC PRINTING. - - -CHAPTER I. - -HALF-TONE PHOTOGRAPHIC NEGATIVES. - -In all the processes and methods treated of up to Part III., the -photographic negative has been what may properly be termed, a black -and white negative, the lines being rendered clear, and the portions -representing the whites of the original being as near black as -possible. The extremes of clearness and opacity in these negatives are -obtained by having the nitrate of silver bath kept and worked in a -very acid state; then the opacity is obtained by intensifying with a -solution of mercury followed by ammonia. - -Now for the methods to be treated of in this part. An entirely -different class of negative is required in which the half-tones -are fully preserved, both in the shadows, and in the lights. These -half-tone negatives may be made either by the wet collodion process, -or upon ordinary gelatine dry plates. For producing them by the wet -collodion process, directions are given on page 11. - -In the processes treated in Part II. the aim has been to get the -photographic half-tone broken up in such a manner that the picture -could be reproduced by the same means as an ordinary wood block, but -in collographic printing the half-tones are not (visibly) broken up, -the gelatine holding the ink in exact proportion to its exposure to -light, thereby giving a print with the smooth gradations of an ordinary -photograph. - -The collographic methods are called “heliotype” and collotype. They -are analogous in principle, but differ in detail; the heliotype is -printed from a film of gelatine, which, after being dried upon a plate -of glass, is stripped off, exposed to light under a reversed negative, -then mounted upon a plate of pewter to support it during the operation -of printing from. The collotype printing surface is the film of -gelatine upon the glass or metal plate upon which it was dried. Note -also the different printing methods. - - -|152| - -CHAPTER II. - -THE HELIOTYPE PROCESS. - -A heliotype print is made in an Albion or other type-printing press, -from a film or skin of bichromated gelatine, which, having been dried -upon a plate glass (finely ground and waxed), is stripped off, then -exposed to light in an ordinary printing-frame, under a reversed -negative, then removed from the frame, laid face down upon a piece of -black velvet, and the back of the skin exposed to light for a short -time. The skin is next mounted upon a pewter plate, coated with a thin -film of India-rubber, and placed upon the bed of the press, where the -skin is covered with water from a sponge, and is allowed to soak for -twenty or thirty minutes. It is then inked up, first with one roller, -and then with another of a slightly different composition; the margin -of the skin is then covered with a mask, with a suitable opening cut in -it, then the paper that is to receive the image is put into position -upon the mask. The picture is then printed. - -The above is a rough outline of the process; now for the working -details. - -First of all, it will be necessary to understand that the gelatine skin -from which the picture is printed must be of such a size as to allow a -margin outside the actual picture of at least two inches all around, -so that the rollers used in inking up will not overlap the margin, and -strip the skin away from the pewter plate upon which it is mounted. -For pictures 10 by 12, and under, a convenient size for the heliotype -skin will be 21 inches by 15 inches, so the present chapter will treat -entirely of skins 22 by 16, and the sizes of rollers, etc., given, as -well as formulas for quantities of gelatine, etc., will be those most -suitable for that size of skin; so if larger skins are adopted, the -quantities here given must be modified accordingly. - -The first consideration will be the apparatus and materials necessary. -The first thing that commands attention is the press—an Albion or -other typographic hand press—(the pressure necessary to print from a -heliotype skin must be vertical, not scraping, therefore a lithographic -press will not do). The press must have the bed fitted with several -thicknesses of Kamptulican sufficient to _nearly_ bring a sheet of -thick zinc type high—“nearly” is said, because |153| due allowance -must be made for the pewter plate (one-eighth of an inch in thickness) -upon which the heliotype skin is mounted. Inside the tympan place a -piece of good blanket, and also provide a loose blanket to lay over the -paper when placed in position for receiving the impression. - -The press must be fastened down to the floor, as plenty of pressure -will be required in printing; a bench will be required close to the -press, upon which either one large inking slab or two small ones can be -placed, as well as the stock of printing papers, and a dish of water. A -couple of good sponges are also required, as well as a supply of thick -plate paper, to blot off the superfluous water. - - -THE ROLLERS. - -The quality of the print from a heliotype skin depends greatly upon -having good rollers at hand for inking the image; therefore, the -preparation of the rollers (two) must be made with every care. Get the -usual printing office pattern, with handles in the centre. The stocks -of these rollers are to be coated with India-rubber sponge, upon which -is cast a mixture of gelatine, etc. - -First of all, procure two 12-inch rollers with handles complete, and -get the stocks coated with India-rubber sponge a quarter of an inch -thick; then, with strong twine tie down about a quarter of an inch from -each end, trimming off the edges outside the string, so as to make them -nice and round; now place one of the stocks in position upon the base -socket of a 15-inch seamless roller mould, then carefully smear the -inside of the mould with a rag saturated with whale oil (taking care -that the whole of the surface of the mould is smeared with the oil); -now place the mould in position over the stock, put the loose socket in -position at the top, when it is ready for receiving the composition for -the inking roller, made as follows— - - Scotch Glue 1 pound. - Gelatine 1 pound. - -Soak all night in sufficient cold water to cover it. In the morning -squeeze out the superfluous water, and in a suitable size glue kettle, -“Baine Marie,” or a jar placed in a pan of water, melt over a fire or -Bunsen burner, then add 1 pound of green treacle, mix, and add 2 ounces -of castor oil, 1 ounce of glycerine; stir well until all are thoroughly -mixed, then pour into a warm jug, and from the jug pour into the mould -as gently as possible; when the mould is full, take a piece of wood, -and tap the outside of the mould all round, from bottom to top. That -will cause any air bubbles that may be imprisoned in the mixture to -rise |154| to the surface; then, if the mixture in setting should -shrink, pour in more until the mould is quite full. - -Now allow to stand for 12 or 18 hours, then remove the mould from the -block, the socket from the top of the mould, then gently push the -roller out. If due precautions have been taken, it ought to come out -quite smooth. If it does not, the composition must be melted off in hot -water, and the roller recast. - -Composition for the clearing roller—Scotch glue, 1 pound; gelatine, 2 -pounds; green treacle, 1/2 pound; castor oil, 2 ounces; glycerine, 1 -ounce. - -The glue and gelatine are soaked as before, then melted and mixed with -the other ingredients. The stock (covered with India-rubber sponge) is -placed inside the greased mould, and the roller cast exactly as before. - -The rollers being pushed out of the mould, trim the ends square with -the ends of the stock, then dip the ends of each roller in hot water -placed in a saucer to a depth of half an inch, until the composition is -slightly softened. In this condition the sharp edges are rounded off -with a damp cloth wound round the fingers. - -The object of thus rounding the edges is to prevent the roller marking -the picture when rolling up the image. - -These rollers are not fit for use directly after casting, but should -be placed on the handles, and washed with turpentine on a slab, then -allowed to hang for two or three days, and occasionally washed over -with a rag dipped in alcohol. - -When in use the inking roller should never be washed, but if the ink -upon it requires cleaning off, it should be done by rolling it upon a -clean piece of hard paper. When put away after a job, the roller should -be coated with fatty ink. Clear it for work next time by rolling it on -the paper. - -The clearing roller will require keeping free from a superfluity of ink -by washing. - -Instead of making the roller composition, and casting rollers, some of -the high class composition sold for type printing may be used, or the -rollers may be obtained ready cast, which will, perhaps, be found far -more economical in the long run. - - -PREPARATION AND CARE OF THE ROLLERS. - -Leather rollers when new should first of all be warmed in front of a -brisk fire, and when warm rubbed with a piece of Russian tallow until -the leather will not absorb any more. Then allow the roller to stand -twelve hours |155| and repeat the operation; then take some middle -varnish, smear some of it along the roller, and on a clean slab roll -vigorously, and repeat the operation two or three times, scrape the -roller with the grain, then roll up in varnish, allow to stand all -night, scrape again, roll up again next day, scrape, then roll up with -collotype ink, scrape and roll up, repeating this until the roller -takes the ink evenly. After each time of using, scrape the roller -before putting away, and if, after using, the roller is likely to be -some time before being wanted again, after scraping smear it with -Russian tallow, and wrap it up in paper, scraping it before rolling it -up in the ink again. - -Glue rollers should be hung up after use in a cold place, and before -being put away should be coated with fatty ink, and just before using -should be rolled clean upon a piece of rather fluffy paper; washing -glue rollers in turpentine is not to be recommended, as it tends to -harden them, and deprives them of their feeding quality. Glue rollers -can be bought ready cast, and it is advisable to so buy them; any -dealer in typographic material will supply them of a suitable quality, -if the purpose for which they are required be stated at the time of -ordering. The “durable” composition being very good for collographic -printing, it may be purchased and used for the rollers, for printing -from a heliotype skin, instead of the mixture given previously. For -roller No. 2, add two ounces of gelatine previously soaked in cold -water, and as much water squeezed out as is possible, then add this to -the “durable” composition, and stir until the gelatine is melted and -well incorporated with the composition. - -These rollers may be cast upon the bare stock, without the India-rubber -sponge, if preferred, but the India-rubber sponge makes the roller much -lighter for use, which is a great consideration when long numbers are -printed straight away. - -These remarks are applicable to the rollers used in the work described -in the previous chapters. Too much care cannot be given to the rollers. -The skilled printer who has feeling for his work will soon learn to -regard his rollers as the magic wands which produce his results. And -well he may. - -The ink used for heliotype printing is the best chalk ink as purchased -in tins, brought to working consistency by mixing with lard, the two -ingredients being well mulled on the slab. Varnish must not be used, -lard being the best. Cocoanut and olive oil are also good. |156| - - -HELIOTYPE SKIN - -is composed of a mixture of gelatine, glycerine, chrome alum, -bichromate of potash, and water, dried upon a slab of thick plate -glass. The surface of the plate glass must be very finely ground with -emery powder (great care being taken that there are no scratches or -holes, or they will spoil the skin), then thoroughly cleaned, and waxed -with a solution of beeswax in benzole, a good plan being to first -of all smear the glass with the wax, and then polish as much off as -possible with an old linen duster (clean), then sprinkle with clean -benzole, and with a fresh duster polish the plate thoroughly, noting -well that wax marks will spoil the skin. - -This waxing need not be done every time a skin is made, but at -intervals of every three or four skins. - -The waxed glass requires levelling, so that the gelatinous mixture -will set of an even thickness; therefore, a levelling stand must be -provided, as well as a good and true spirit level. - -The gelatinous mixture is dried in an oven (see Drying Oven in chapter -on Collotype), at a temperature not exceeding 80° F., the time occupied -being from thirty to forty hours. - - -THE PEWTER PLATE. - -The skin after exposure to light under the negative, etc., is mounted -by means of a squeegee upon a plate of pewter 21 by 15 by 1/8 of an -inch in thickness, and well polished. This plate is cleaned with -benzole and coated with a solution of India-rubber in benzole (well -filtered) and dried. - - -THE MASK. - -To prevent the margin of paper upon which the ink picture is printed, -being dirtied, it is necessary, after rolling up, to lay a mask over -the skin, this mask having an opening in the centre the size of the -picture. Paper suitable for this purpose is made by coating bank-post -paper with a mixture of one part of gold size, and two parts boiled -oil; this mixture is laid on the paper evenly with a sponge, then hung -on a line to dry; when dry it is ready for use. - - -THE HELIOTYPE SKIN. - -To prepare a skin 22 by 16, weigh out two ounces of a good gelatine, -and soak it in ten ounces of cold water until soft, then place it in -the porcelain |157| vessel of a “Bain Marie,” the outer vessel being -duly provided with the requisite quantity of cold water; now place it -over the fire or Bunsen burner, and stir until the gelatine is just -melted, then add two drachms of glycerine; stir well, so as to mix -thoroughly, and raise the temperature to 125° F.; add two ounces of -solution No. 1, and two drachms of solution No. 2; stir well, then -remove from the fire or Bunsen, and strain through muslin into a jug or -beaker; now tie over the jug or beaker a clean piece of muslin, when -the mixture is ready for pouring upon the ground side of thick plate -glass, waxed, properly levelled, and slightly warmed. Begin by pouring -in the centre of the plate, and gradually enlarge the circle until all -the gelatinous mixture is out of the jug or beaker, then with a strip -of clean card coax the gelatine to the edges. - -Now examine the film for air bubbles, which, if present, must be -removed, either by pricking with a quill toothpick, or by coaxing to -the edge with a piece of card. - -As soon as the mixture has thoroughly set (which it soon does), remove -it to the drying box. - -Of course, the requisite quantity of gelatine for more than one skin -may be melted at once, but it will be better only to strain into -the pourer, from the “Bain Marie,” sufficient for one plate at a -time, remembering that the quantity now given is for one plate only; -therefore, if two, three, four, or more plates are to be dried at once, -the quantities given above must be increased accordingly. - -The stock solutions named above are compounded as follows: - - -_No. 1._ - - Bichromate of Potash 1 ounce. - Water 20 ounces. - - -_No. 2._ - - Chrome Alum 1 ounce. - Water 20 ounces. - -The temperature of the drying box must not exceed 80° F., and the time -occupied will be from thirty to forty hours, during the whole of which -time the temperature must be steadily maintained, but not exceeded. - -When the skin is dry, with the point of a penknife separate the edges -from the glass, and then lift the skin away, when it is ready for -exposure to light under the negative. If it is desired to keep the -skins a few days before using, they may be stored between sheets of dry -brown paper in a drawer, or in a tin tube. |158| - -It will be just as well to remark here that the dry heliotype skins -are sensitive to light; therefore, the drying oven must be in a room -illuminated by yellow light, or by artificial light, and the skins must -not be exposed to daylight until they are in the printing frame. - - -PRINTING THE PICTURE. - -The heliotype skin is now ready for exposure under the negative, which -is done in a printing frame 24 by 18 inches, provided with a plate -glass front. - -The negative must be reversed (_i. e._, instead of being taken direct -in the usual way, a reversing mirror is used). The margin of the -negative must be protected by a mask, with an opening cut the size and -shape of the intended picture, the outside edges of the mask being -sufficient to cover the rest of the skin. - -To print, the back of the negative is cleaned, then laid with the film -uppermost, in the centre of the plate glass front of the printing -frame; the mask is then laid in position, the opening in the centre -being adjusted so that exactly the amount of picture required will -be printed upon the skin. The rest of the skin is protected from the -action of light by the opaque margin of the mask. Now lay the skin, -with the matt surface (_i. e._, the side that was in contact with the -ground side of the glass plate during the process of drying) next the -film of the negative; upon this lay a piece of dry black velvet, then -a sheet of thick felt, then the back of the printing frame, fasten up, -turn it over and see that the front of the glass is clean; then the -frame is ready for exposure to light. - - -EXPOSURE TO LIGHT - -should be made in a good diffused light, and its duration timed by -means of an actinometer (see page 107). - -As the time of exposure to light will vary according to the quality of -the negative, no precise rule can be made, the best way being to get a -small negative as near the same density as the other, cut off a piece -of the skin, and placing it in a frame, expose to light at the same -time as the big frame, and occasionally examine the progress of the -small strip of skin in the dark room. A very good idea of the exposure -of the big one can thus be had. A heliotype skin is properly printed as -soon as the details in the half-tones show themselves. Of course, it -should be understood that the small negative must be exposed to light -at the same time and place as the big one. |159| - - -SUNNING THE BACK OF THE SKIN. - -The exposure to light under the negative being completed, remove the -skin from the printing frame, and lay it with the side that has just -been in contact with the film of the negative, upon a piece of black -velvet, covering the margin of the skin outside the picture with strips -of brown paper—these strips not quite touching the picture; now cut -off a strip of the skin, say a quarter inch wide by one inch long, -and double it lengthways, then cut a hole in a piece of brown paper -and place the doubled piece of skin under it. Now remove the skin to -diffused light, and as soon as the shape of the hole can be seen upon -the undermost half of the small strip, the sunning of the skin has gone -far enough, and it is ready for mounting upon the pewter plate. - -The test here given for timing the sunning of the exposed skin is -suitable, when a good ordinary negative has been used, but if a -negative somewhat flat, or thin, has been used, then less sunning will -be required, and if a very intense negative, the time of sunning must -be increased, the object of the sunning being to reduce the relief -caused by deep shadows. - - -MOUNTING ON THE PEWTER PLATE. - -The pewter plate upon which the exposed and sunned heliotype skin is -mounted for printing from, must be well polished, free from scratches -or other marks, the size being 21 by 15 by 1/8 of an inch in thickness. -This plate is polished with a soft duster, then coated with a solution -of India-rubber in benzole (about the consistency of sweet oil), the -solution being poured on, and flowed to the corners and edges; then the -plate is placed upon a levelling stand, and the India-rubber allowed to -dry. - -This India-rubber solution is made by dissolving India-rubber solution, -as sold in tins at any India-rubber warehouse, in benzole or benzoline. - -When the solution is made it must be filtered through paper, or -strained through five or six thicknesses of fine muslin, as the -presence of any grit between the surface of the pewter and the skin -would at once ruin the picture. - -The India-rubber film being dry, place the pewter plate in a tray of -clean water, the water being about a quarter of an inch deep; now trim -the skin with a sharp pair of scissors to a little smaller than the -pewter (20-1/2 by 14-1/2), then lay the skin, face up, upon the surface -of water, and at once lift the pewter plate from the water, keeping -the skin in position by grasping the two top corners with the two -forefingers. Now lay the pewter on the bench, and |160| with a nice, -soft squeegee bring the skin into contact with the India-rubber film. -This mounting must be done rapidly, as if the skin gets a chance of -absorbing water it will frill, and be spoilt. The back merely requires -moistening, and the squeegee, in expelling the water, brings it into -contact with the India-rubber film. Now, with the squeegee, remove all -the water from the plate, and then brush round the edges with some -India-rubber solution, so as to reduce the chance of water, to be used -subsequently, from getting under the skin. - - -PRINTING FROM THE SKIN. - -Now place the pewter on the bed of the press, and with a clean sponge -cover the picture with clean, cold water, in sufficient quantity to -form a pool about one-eighth of an inch deep, care being taken that the -water does not extend as far as the edges of the skin. - -The water is allowed to remain on the skin for five minutes; it is then -soaked up, and a fresh supply added, and this operation is repeated -at intervals for twenty or thirty minutes, the object being to partly -remove the bichromate, and also to allow the gelatine that has not been -rendered insoluble by the action of light, to absorb sufficient water -to enable it to repel the ink from the roller. - -When it is judged that the image has been sufficiently soaked, with -the sponge remove as much water as possible, then lay a clean sheet of -paper upon the skin; upon the paper lay the loose blanket, lower the -tympan, run the bed of the press under the platen, then pull over the -lever, and subject to as much pressure as the press will give, allowing -the pressure to “dwell” for a minute or two. - -This is to “smash” down the highest relief in the skin, which, unless -so smashed down, would interfere with the roller feeding the ink in the -deepest shadows. - -The skin is now ready for inking up with No. 1 roller, charged with -the best litho. ink mixed with a little lard, just sufficient, and no -more, to make the stiff ink distribute on the slab, the ink and the -lard being thoroughly incorporated, either with a stiff palette knife -or with a muller. The ink and lard being thus well mixed upon the slab, -gather up the compound and place it in one corner of the slab. - -For No. 2 roller take a portion of the above mixture and add to it a -little more lard, and mix well, then place this in one corner of the -other inking slab. - -With the palette knife touch the roller No. 1 at short intervals with -little dabs of the first ink, then roll it vigorously on the slab up -and down, and then |161| across and sideways, until the ink is evenly -distributed over the roller and the slab; now with the roller proceed -to ink up the image. Use plenty of pressure, and turn the roller first -one way, then the other, until the image shows itself vigorous and -strong. - -Now take No. 2 roller charged (in the same way as No. 1) with No. 2 ink -well distributed (but do not use quite so much as with No. 1), and with -a light pressure go over the inked image; this inking will fill up the -light half-tones and clean up the image generally. - -Before pulling an impression take a sheet of mask paper (which must be -a little larger than the pewter plate), and in the centre cut a clean, -sharp opening the size the picture must be. This mask, with the oiled -side down, is adjusted in position on the skin; then turn back the edge -furthest from the operator, and upon the extreme edge of the pewter -place a few small dabs of stiff ink, return the margin of the mask over -these dabs of ink, and rub down; these dabs of ink serve to keep the -mask in position, when turned back for each inking up. If the margin of -the mask paper projects over the pewter plate, and outside the bed of -the press, it must be turned down, else it will tear when the bed of -the press is run in. - -The mask being laid in position to protect the margin of the print, -lay a piece of matt enamel paper on the inked up and masked image, -back this first with a sheet or two of clean blotting paper, then with -a loose blanket; lower the tympan, and run the bed of the press under -the platen and pull over the lever. The pressure requisite to pull -an impression from a heliotype skin requires the full strength of an -ordinary man to pull over the lever. - -Now examine the print, and if it is flat and dirty, the skin has not -been soaked sufficiently before inking up, so remove the ink left by -the paper by washing it over with a rag soaked in turpentine, then wash -with a wet sponge, blot off the surplus and with the sponge again put -a pool of water over the image, and allow it to soak for about five -minutes; again wipe it off with a sponge, smash down and ink up again. - -If the image is black and white without half-tones, the fault may lie -in the negative, which perhaps is too hard; or if that is all right, -then the skin has not been sufficiently exposed in the printing frame, -in which case it may be at once thrown away, as no amount of coaxing -will make it yield a good print. Or it may be that the skin is too -damp, in which case rub it gently with the water sponge, on which a few -drops of alcohol have been sprinkled; then blot off, ink up again, and -pull another proof. |162| - -If the back of the skin is “sunned” too much, the print will suffer by -being dirty and flat, and will require sponging over with a little of -the ten per cent. mixture of ammonia in water; then blot off, and again -ink up; take care and keep the ammonia sponges away from the other -sponges. - -If the deep shadows show a white margin and are difficult to ink up, -the skin has been exposed under the negative for too long a time; and -if “smashing” down does not remedy the defect, the only chance of -saving it will be to allow the skin to get thoroughly dry, and then -(say the next day) to soak it up again for an hour. - -Spots on the margin of the print may be removed by carefully painting -them over with a camel’s-hair brush charged with dilute cyanide of -potassium, carefully washing afterward to prevent spreading. - -Each time the image is inked up, the mask must be laid back, so as not -to interfere with the roller; then after inking up, it is again laid in -position, so as to protect the margin of the paper upon which the print -is made. - -It must be borne in mind that the first print from the skin will not -be the best it is capable of giving, therefore, before any of the -above-named dodges are resorted to, the image should be inked up and -proofs pulled four or five times; as a generul rule perfection will not -be attained until about ten or twelve prints are made, using each time -a good paper, as a soft spongy one will not pick up the ink on the skin. - -Of course, a plain black ink will not suit every class of subject, -therefore, when the operator requires a different tint or color, it -must be made by a judicious blending of stiff ink of the proper colors -mixed with lard as given above. When a distinct change of color is -required, it is not a good plan to wash No. 1 roller, but have a -separate No. 1 roller for each color. No. 2 roller may be washed for -such a purpose. - -If it is desired to print two tints, the darkest tint is applied with -the No. 1 roller, the lightest with the No. 2 roller. - - -|163| - -CHAPTER III. - -THE COLLOTYPE PROCESS. - -This process, roughly described, consists in carefully grinding with -fine emery, a plate of thick glass, then coating it with a mixture of -white of egg, or of stale beer and silicate of soda. After the plate is -dried it is rinsed in water, and dried again, then warmed, and coated -with a thin film of bichromated gelatine. This coating is then dried -in a suitable oven, after which the plate is exposed to light under a -reversed negative, followed by a short exposure of the back of the film -to light, then washed in cold water until the whole of the bichromate -is removed from the film, when the plate is allowed to dry. It is next -soaked in cold water, then in a mixture of glycerine and water, after -which it is placed upon the press, and the printing proceeded with. - -As in lithographic printing, the size of the paper upon which the -picture is printed determines the size of the stone upon which the -transfer is made, so as to give a good margin, not only large enough -to prevent the paper being marked by the edge of the stone, but also -to allow plenty of room for working the roller; so in collographic -printing, the glass plate upon which the picture is to be made must -be sufficiently large to allow a margin of _at least_ four inches all -round the outside of the picture. This is not only requisite for the -reasons that hold good in litho. printing, but for the additional one -of giving plenty of room for the manipulation of the mask used to -protect the margin of the print. - -Collographic plates should also be sufficiently large to prevent their -edges from cutting the composition rollers used for inking the image; -for instance, a roller nine inches long should never be used upon a -plate less than twelve inches wide. - -Collographic films are made upon good patent plate-glass half an inch -thick, free from scratches, with the edges nicely bevelled to avoid -cutting the rollers; this bevelling the plates is absolutely necessary -for use upon the machine, but is not so important for the hand press. - -To prepare plates for use they are first ground with fine emery powder. -To do this place one plate upon a smooth board or a couple of bearers -across the sink, sprinkle with fine emery powder (sifted through book -muslin), then with |164| water. Now, with another plate on the top, -proceed to grind with a circular motion, continuing the grinding until -the emery is worn smooth; then renew the supply of emery, sprinkle with -water and again grind until the emery is smooth; now work well with -water, squeegee dry, and examine the surface; if it is evenly ground -the plates are ready for the next stage. If they are not ground all -over, cover them again with emery and water, and continue to grind -until the surfaces are of an even matt all over. - -The plates being ground, they are well rinsed under the tap, and both -sides are well rubbed with a rag to free them from all particles of -grit, etc., then flood them with a mixture of - - Liquor Ammonia 1 ounce. - Alcohol 1 ounce. - Water 5 ounces. - -rub this well in with a clean rag, and again well wash with clean -water, then allow to drain and flood with - - -THE PRELIMINARY COATING OF - - Stale Beer 5 ounces. - Water 5 ounces. - Silicate of Soda (Waterglass) 2 ounces. - -made up an hour or two before using, and filtered. - -The wet plate is covered with this two or three times, and then placed -on a rack to dry. When all the plates in the batch are coated the rack -should be removed to the drying oven and the plates dried _in sitû_, -not lying down. - -Be as careful as possible to prevent any of the beer and silicate -mixture from getting on the back of the plate, as it interferes with -the running of the image afterward. - -Plates may be prepared with the preliminary coating in quantity, as the -coating hardens and improves by being kept. - -When the coating on the plates is quite dry rinse them under the tap -and again dry them, this time quite spontaneously. Lastly, they are -placed upon the slab of the drying oven to get sufficiently warm before -being coated with the sensitive mixture. - -The sensitive mixture must be made exactly as follows, as everything -depends upon the time and temperatures named: First of all, take thirty -ounces of pure water and add ten drops of a saturated solution of -chrome alum; shake up well and allow to stand ten minutes; if the water -is very slightly opalescent, it is |165| quite satisfactory, but if -there is any tinge of green then too much chrome alum has been used, -and it must be thrown away and another lot made. - -Then add two and one-half ounces of fine gelatine and allow it to -soak until soft, then place it in the “Baine Maire” and melt the -gelatine, stirring all the time. Raise the temperature to 125° F. and -keep it thus for fifteen minutes; next add 150 grains of bichromate -of potassium in fine powder, stirring until dissolved, and raise -the temperature to 150° F. Strain the mixture through muslin into a -porcelain jar and allow it to cool, keeping it in jelly at least twelve -hours before using it. - -This sensitive mixture does not work well if used to coat plates -with directly it is made; therefore, it must be made up some time in -advance. It keeps well, in fact improves, with keeping, up to about -seven days. In remelting for use, only melt just sufficient for the -plates to be coated, as it does not improve it to melt it too often. - -Plates coated with the above mixture are dried at a temperature of from -100° to 120° F. in from two hours to three hours, and have a splendid -grain. - -Here is another formula the mixture from which does not keep, but -must be made and used directly. It is the formula most frequently -used by the writer. Plates prepared with it can be dried, at lower -temperatures, in from twenty to fifty minutes. It is also the best -formula when copper plates are used instead of glass, of which mention -will be made at the end of the chapter. - -Soak two and one-half ounces of gelatine in fifteen ounces of water -until quite soft, then place all in the “Baine Maire” and melt at as -low a temperature as possible; when melted add 100 grains of bichromate -of potash and 50 grains of bichromate of ammonia both in fine powder, -stirring until dissolved; now put in the thermometer, and raise the -temperature to 140° F. and keep it there for ten minutes; then allow -to cool to 125° F. and add the following mixture, stirring vigorously -the while: fifteen ounces of alcohol and five ounces of a saturated -solution of borax in alcohol. Mix the two before pouring them into -the hot gelatine. With some gelatines the addition of this mixture -will cause a slight coagulation of the gelatine, and it will stick to -the stirring rod; therefore, the solution must be stirred until the -coagulated gelatine is redissolved; then strain it through muslin into -the pourer and at once use it by pouring it over the warm plates. - -One of the best vessels to use as a pourer is an invalid’s cup with a -spout at the side. - -The above quantity of mixture is sufficient for sixteen plates 16 × -13 inches; |166| therefore, if only four are to be coated, which is -the quantity that the drying oven to be described will take, the above -quantities must be divided by four. - -Now if the first formula be used, take sufficient of the jelly, -melt it and strain it through muslin; then take one of the plates -from the drying oven—which plate should be just warm enough to be -comfortably held on the palm of the hand—carefully brush it over with -a dusting-brush, so as to remove any particles of dust that may have -adhered and balancing the plate on the palm of the hand, pour over it -sufficient of the warm gelatine to just cover it. A 16 × 13 plate will -take a little less than two ounces of the gelatine mixture. Take care -not to spill any. Next place the plate upon the hot slab, and coat the -rest in the same way. When all are done close the door of the oven and -do not open it again until the plates are dry. - -With the second formula the _modus operandi_ is the same, except, of -course, that instead of melting the already made jelly, the mixture -made as above directed is used directly after mixing. The plates being -dry they are ready for exposure, which need not necessarily take place -at once, as if stored away in the dark and away from damp they will -keep two or three weeks. - -The exposure to light is made in a box-pattern frame, the negative -having a mask in front of it to protect the margin of the plate from -the light. - -The negative used must be reversed—_i. e._, the image must be in its -right position on the negative when viewed through the film, not as -ordinary negatives are—through the glass; therefore, a mirror must be -used in making the negative, or a skin negative may be used; or, if -neither is practicable, the negative must be reproduced by one of the -methods already given. - -The exposure to light in the printing frame will vary according to the -density of the negative, and the strength of the light, and should be -continued until the image can be seen well defined upon the gelatine -film when examined in the dark-room, by opening one-half of the back of -the frame. - -The exposure being complete, lay the printing frame face down upon a -table in the light, remove the back and packing, and expose the back of -the film to the light for a short time, without in any way disturbing -the position of the collotype plate or the negative. - -This exposure of the back of the image to the light has a twofold -advantage, one being that it helps to weld the sensitized gelatine film -to the surface of the plate, and so enables it to stand the wear and -tear of printing; the other, that it reduces the relief of the picture, -and so gives the inking roller a better chance of feeding the deep -shadows. |167| - -The duration of the exposure of the back of the film to the light will -vary very much with the subject in hand; if it be one with slight -contrasts, a much shorter time will be required than where the picture -contains a lot of very heavy shadows. - -The next step will be to remove the plate from the printing frame, and -immerse it in clean cold water for five or six hours, or for such a -time as suffices to remove the whole of the bichromate from the film. -The plate is then placed in the rack to dry spontaneously, and should -be allowed to stand for at least twelve hours afterward before printing -from, so as to give the film a proper chance to become thoroughly hard. - -We now have a collotype plate which has undergone the following -operations, viz.: - -A plate of thick glass ground with fine emery until of an even matt -surface. Then it is washed and coated with the preliminary coating of -beer and silicate of soda and dried. Then rinsed in cold water and -again dried. Next placed on the warm slab of the drying oven until just -warm enough to hold on the palm of hand. Then coated with the sensitive -mixture, either No. 1 or No. 2, and placed in the oven until dried. -Then exposed to the light under a reversed negative in a printing frame -until the details of the image are well out. Then the back of the plate -is exposed to the light for a short time. Then it is placed in clean -cold water until the bichromate is removed. At last the plate is dried, -after which it is ready for the printer. - -[Illustration: Fig. 17.] - -Now, before proceeding further, it will be as well to touch upon -various points of procedure, and also to describe what may be reckoned -the most important piece of a collotype plant, viz., the drying oven. -Figure 17 gives a drawing of the oven as it stands on the table for -use, the |168| dimensions being from the top to the bottom of the -frame 5 feet by 3 feet 4 inches wide by 3 feet deep. The top A, and -the back, are covered with matched boards well seasoned; the sides -and front, B, B, B, B, are made of frames 2 inches by 1 inch, covered -with canvas sufficiently close to exclude light, but still open enough -to let out the heat slowly. The door C is also a frame covered with -canvas, 24 inches square, sliding upward in grooves, and balanced -by means of weights. D is the jacket of iron upon which a copper -tank rests, the jacket serving to carry the tank and to protect the -wood-work from the gas flame used to warm the water in the tank. E is a -sliding door in the jacket for the purpose of lighting the gas burner. -F F are the projecting ends of a levelling arrangement forming the base -of the oven, these ends being fitted with good, strong screws working -upon iron plates let into the top of a strong table upon which the oven -is placed. The distance between the two lower rails or styles is 6 -inches, which is also the height of the iron jacket. D G is a tube let -into the jacket to carry off the products of combustion from the gas. H -is a tube with a screw nozzle, for filling the tank. - -[Illustration: Fig. 18.] - -[Illustration: Fig. 19.] - -[Illustration: Fig. 20.] - -Figure 18 is the base of the oven, _A A A_ being the three points where -the levelling screws are placed; this base is formed of good 4 by 3 -inch quartering, the other dimensions being as marked. This base stands -on the table, the oven on the top, without any fastenings. |169| - -Figure 19, the jacket of sheet iron well wired, with a tube at one -corner, for carrying off the products of the combustion of the gas, and -a hole at the other corner to carry the projecting tube from the tank, -by which it is filled. - -Figure 20, the copper tank, the outside dimensions of which are 37 by -31 inches, the flange fitting on top of the jacket; the depth of the -tank in the centre is 3 inches; the inlet pipe is 1 inch bore, and 6 -inches long, the bend being taken high enough to be about 2 inches -above the top of the tank. - -The base is placed upon the table, then the iron jacket on the top of -the base; then the copper tank is fitted into the top of the jacket; -upon the top of the tank is placed a slab of marble or slate 37-1/2 by -31-1/2 inches, cemented by means of plaster-of-Paris. The wooden top of -the oven is fitted into position, the canvas being nailed on last. But, -before doing this, it will be as well to fix the bearers as at C C C, -Fig. 21, with corresponding ones on the other side, so that slats may -be placed across for the purpose of holding heliotype plates, and for -drying transfer paper, etc. The interstices between the edges of the -slab and woodwork should be made good, either by means of wooden laths -or cement. - -[Illustration: Fig. 21.] - -The oven being erected, the first thing to do will be to fill the -copper tank with water; then level the slab by means of the screws, or -if the bottom ends of the base are shod with sheet iron, wedges may be -used to level with. The drying oven must be kept in a room at a uniform -temperature of about 60° F. - -In using the oven after the plates are dry (after rinsing), place a -piece of clean, dry, brown paper upon the slab, then place on this -paper four plates 16 by 13 inches—which are the size and quantity for -which the dimensions of the oven have been calculated; then place a -thermometer between the plates, and close the oven. After the water has -been brought to boil, the plates will be ready for coating; but, if the -thermometer registers over 120°, turn off the gas, coat the plates, -again close the door, and let the plates dry. - -One of the first things the student must do is to familiarize himself -with the oven. Note the time taken to bring the water to boil; the -temperature of the |170| slab, and the time taken for the temperature -to fall after turning off the gas. A day spent at this will teach far -more than it is possible to do by writing. - -Do not try to improve the oven by having the door to open any other way -than by sliding. If made to open in or out, a draught of air is created -which will cause mischief. Petroleum, instead of gas, may be used for -heating the water. - -Instead of using glass plates for carrying the collotype film, copper -or brass plates may be used. They should be grained with fine sifted -graining sand and a stone muller, then washed with plenty of fresh -water, and coated with - - Stale Beer 5 ounces. - Water 5 ounces. - Silicate of Soda (syrup) 2 ounces. - Tannin 1 grain. - -Prepare the mixture three or four hours before using, and filter it -carefully. The subsequent operations are the same as with glass, except -that the sunning of the back of the film must be dispensed with, and -the second formula for the bichromated gelatine mixture must be used, -as the first one gives too high a relief for copper. - -Plates that have been used are cleaned again for further trial, by -immersing them in a pickle of American potash or concentrated lye, then -well washing, regrinding, washing, and finally coating with the beer -and water-glass substratum, exactly as before mentioned. - - -|171| - -CHAPTER IV. - -PRINTING FROM THE COLLOTYPE PLATE. - -Collotype plates are usually printed from, upon a typographic press, -but the best press is one with a cylinder, like the lithographic -machines. Such presses give a more even pressure, and at the same time -will enable more impressions to be made in a given time. - -In the chapter on heliotype printing, a description is given for -preparing the tympan for printing from the heliotype skin, and that -description holds good for collotype plates; but we shall require a -slate slab, the full size of the bed of the press, and a little under -half an inch in thickness, upon which to fix the collotype plate by -means of plaster of Paris. - -The press being ready, take the dried plate, and soak it for half an -hour in clean cold water. After that wipe it with a clean soft rag, and -scrape any gelatine from the back that may have found its way there; -spread as evenly as possible some fine plaster of Paris over the slate -slab on the bed of the press, then damp with sufficient water to make -the plaster the consistency of cream, and lay the damp collotype plate -in the centre, and press it well down, working it a little so as to -get it level and well bedded in; allow the plaster to form a ridge all -round the edges outside the plate, levelling these ridges by running -the finger over the moist plaster, so that they do not project above -the face of the plate. Now cover the collotype plate with a mixture of - - Glycerine 5 ounces. - Water 10 ounces. - Ox-gall a little. - -Allow this fifteen minutes to permeate the film, taking care that it -covers the whole of the surface evenly. - -Whilst the plate is thus soaking up, get the inking slab clean, and the -two rollers ready, viz.: An ordinary lithographic roller, for inking up -the heavier portion of the image, and a composition roller for inking -the half-tones and clearing the image; then mix the ink to the desired -shade by taking some stiff ink from the tin, and mixing to the proper -consistency with a little olive oil. The ink must not be made thin, but -just sufficiently softened to work up with |172| the palette knife. -The ink used must be very finely ground by machinery with a minimum of -olive oil. This, in hand grinding, is difficult to do, and the presence -of too much varnish in the ink is prejudicial to the production of -bright collotype prints. - -The ink being mixed, a little is taken up on the point of a palette -knife and smeared along the face of the leather roller and then -worked vigorously upon the inking slab, until the ink is thoroughly -distributed upon both roller and slab. Do not attempt to thin the -ink so as to lessen the labor of distributing the ink, as that will -only render the collotype print flat and weak. The ink must be stiff -and spare. Now remove the soaking fluid with a very soft sponge, and -blot off with fine plate paper, then proceed to roll up with the -leather roller, until the image just shows nicely on the plate. Do not -attempt to get it to take sufficient ink to look black. Next take the -composition roller, and a little ink thinned with lard to about half -the consistency of that used with the leather roller, and touch it -here and there with the palette knife holding this thinner ink, and -roll up on another slab until the ink on the slab and roller are quite -even; now apply the composition roller to the image inked up by the -leather roller, and roll with a light pressure and quick motion. This -will complete the inking up of the image. Now take a piece of the mask -paper mentioned for heliotype printing, and having cut out a suitable -aperture, place it in position upon the plate, then put a piece of -paper in position upon the mask; upon this paper fix a large sheet of -smooth waste paper, then loose the blanket, lower the tympan, run the -bed of the press under the platen, and after adjusting the pressure, -pull over the lever, run out the bed, and examine the proof. From that -deduce whether the ink is too thin, or too thick, or not enough, or too -much. Damp with a sponge dipped in water, then blot off or remove the -surface water with a damp soft rag, then ink up again, and repeat until -a suitable print is the result. - -Some collotype blocks require the ink far thinner than others, -therefore it will be the aim of the printer to try various degrees of -ink with each plate until the best result is attained. The best prints -are got, as a rule, from a roller that seems to have very little ink -upon it, but the ink thoroughly well distributed over both slab and -roller. - -To print from a collotype plate it is necessary that those portions -of the film which have not been exposed to the light—and from them in -proportion as the gradation of tone progresses to the shadows—must be -charged with moisture to enable them to resist the greasy ink; if plain -water be used for this it would |173| be troublesome to get sufficient -in the film to resist the ink, and at the same time enable the roller -to feed the image without slipping. Therefore glycerine is used, mixed -with water, and with various hygroscopic substances, to which the term -“etching fluids” has been given. This term is a misnomer, and quite out -of place, “damping fluids” being the best. - -In addition to the damping fluid previously given, a few others are -here appended, each having their advantages under certain conditions: - - Glycerine alone or with water. - -or, - - Glycerine 5 ounces. - Water 5 ounces. - Hyposulphite of Soda 1/2 drachm. - -or, - - Glycerine 5 ounces. - Water 5 ounces. - Nitrate of Potash 1 drachm. - -or, - - Glycerine 5 ounces. - Water 5 ounces. - Ammonia 10 drops. - -or, - - Glycerine 5 ounces. - Water 5 ounces. - Common Salt 30 grains. - -or, - - Glycerine 5 ounces. - Water 5 ounces. - Chloride of Lime 1 drachm. - -The last one must only be used when it is desired to take away a -tint, and if used too often, will be very likely to destroy the image -altogether. - -During the printing from a collotype block, the number of impressions -that may be pulled without redamping, will vary very much with each -block. Sometimes as many as eight or ten may be pulled, but the average -will not exceed two. As soon as there is a tendency to flatness, take -a sponge containing a little of the damping fluid, and go over the -film with it, then wipe it off |174| with another sponge, or a piece -of damp cloth (soft), then blot it off with a piece of good blotting -paper, and ink up again. In fact, as a rule, it is best to damp for -each print. - -Good printing paper must be used for collotype prints, and for very -fine work a fine neat enamel paper will be best. Coarse hand-made -papers, however much admired, must soon break up the delicate image. - -[Illustration: Fig. 22.] - -I will describe another drying oven, the heating arrangement of which -is the same as the other, but the superstructure is much smaller. It -will require more care during the time the coated plates are drying -to keep the temperature down, but it has the advantage of allowing a -thermometer being inserted in the lid in such a manner as to allow -the temperature of the interior being seen at a glance. Still another -advantage is, it takes up much less room. It measures inside 18 inches -wide by 32 inches long, and 9 inches deep to the top of the slab. The -thickness of the slate slab and of the copper tank should be the same -as in the larger oven; the lid at the top should be made solid and have -an orifice in the centre through which the thermometer is pushed. The -sides of the oven should be covered with one or two thicknesses of good -red flannel. - -The only thing that calls for particular attention in these ovens is -the copper tank, which should (especially the top) be made of good, -stout sheet copper, otherwise the water on being heated has a tendency -to make the copper bulge, and elevate the slab. By that means the care -which should be taken in levelling the slab will be lost, as this -elevation will put it all out. Before putting the superstructure in -position, the slab must be cemented to the top of the copper tank by -means of plaster-of-Paris; this is important, as a much more even heat -is thus obtained. - -Now, whichever oven is decided upon, it must be erected in a room free -from draught, where it can be kept at a temperature of 70° F., as the -quality of the collotype plate is much influenced by the temperature of -the room in which it is prepared. So, too, is the oven in which it is -dried, especially if below 60°, for then it is very difficult to get -good results, as the plate chills when taken from the oven, and the -film is almost sure to prove rotten during the printing. |175| - -In the summer time, if the room gets too hot, the gelatine solution is -apt to get frothy, and then dry hard and glossy, instead of with a nice -half-mat surface. It is then best to prepare the plates only in the -early morning. - -The temperature at which to dry the collotype plates will vary -according to the subject to be printed upon them, as some subjects will -require a finer grain than others. But a few intelligent experiments -will soon enable the operator to judge of the temperature required; -75° F. is the lowest, and 120° F. the highest temperature giving good, -bright blacks. - -One of the great secrets in collotype is to give a double coating to -the plate. I find it really a great advantage so to do. I found this -out quite by accident. One day, when I went to use some plates, I -found that they had not been properly levelled, and that the coating -was thin at one end, and thick at the other. This happened to three -out of a batch of four, the other one being all right; so, in a fit of -laziness, or hurry, or something, I decided on recoating the three, and -did so. When I came to print from the three twice coated and the one -once coated, I was agreeably surprised at the difference; the pictures -on those twice coated were much more vigorous. Since then I have tried -the experiment exactly, and always get the same uniformly excellent -results. The second coating is applied as soon as the first is dry; -but this second coat cannot be applied so well if the plate be held on -the hand, therefore a levelling stand should be used, and the gelatine -poured on the centre and coated over the surface by means of a glass -rod. - -The proper quantity of gelatine solution requisite for a plate 16 by 13 -inches is 2 ounces for each coat. Note well that all of it is left on -the surface of the plate, not some on the table. - -When once the coated plates have been placed in the oven, and the -lid is closed down, they must not be disturbed until they are dry; -this will be in two or three hours, according to the thickness of the -coating of gelatine. If removed before they are dry, there is danger of -marking the film. - -After the second coating of gelatine is dried, the plate will be all -the better if kept a few hours before being printed upon, care being -taken to store it in the dark, or somewhere free from damp and gas -fumes. - -By the bye, the oven must be placed in a room illuminated by yellow -light—_i. e._, daylight filtered through yellow glass, cloth, or paper; -or else the room must be lighted by gas or oil light. - -The negative to be printed from should have all the parts that are -intended |176| to be quite white in the finished print, stopped out -with India ink or Gihon’s opaque, and the limit of the picture should -be masked by very thin tinfoil, cut quite straight and gummed upon the -film side of the negative. The rest of the margin of the plate must be -protected by a brown paper mask. - -The best printing frames for collotype printing are of the box (or -“deep”) pattern, with plate glass fronts. They should be about two -inches deep, and the bars behind quite plain—_i. e._, without either -screws or springs. The back board should also be dispensed with, the -pressure being got by means of wedges. The advantage of these frames is -that the picture can be examined without undoing the back, and without -risk of shifting the plates. - -After printing, the plate should be placed in a zinc vessel like -a plate box fitted with a siphon, so that the water can be kept -constantly changed, until the bichromate is removed; then the plate is -drained, and, after being wiped with a soft cloth, is put away to dry. - -Now then, beginners, do not be in a hurry to try your first plate on -the press directly it is free from the bichromate, as no plate will -give a good result until it has been dried down. Before putting it on -the press, soak it for half an hour in water, then half an hour in -glycerine and water in equal parts, and, finally, wipe it, and proceed -to ink up the press. - -The safest plan is the one mentioned, viz., bedding up slate with -plaster-of-Paris. Another plan is to place on the iron bed of the press -a piece of thin felt, then a slab of glass, upon which are placed two -thicknesses of wet blotting-paper; upon these place the collotype plate -(the back of which is free from any gelatine that may have run over -after coating); then, if a chase be placed on the press, the plate may -be blocked in position by means of a few pieces of furniture tightened -by means of quoins. - -In the above only glass slabs are treated of; but brass plates, about -one-eighth of an inch thick, will be found safer, and more economical -than glass, and yield results just as good. They may be fixed upon a -block of hard wood by means of a screw (countersunk) at each corner. If -an ordinary type press is not at hand, brass plates may be printed from -upon a litho. press. - -Whether the plate will require damping each time will depend greatly -upon each individual plate and the subject. With some, damping must -be done each time; with others, once only for four, six, up to a -dozen pulls; but, of course, the temperature of the room in which the -printing is conducted will be an important factor in determining this -point. When the print is flat, and the whites degraded, then damp the -plate before again inking up. |177| - -To insure even prints, care must be taken to keep the roller well -charged with ink. Much more could be written on this subject, but -practice will be the best guide. - -A word as to bedding the glass slab on. With a properly prepared -leather litho. roller, charged with ink mixed with a little olive oil -and varnish, brought to a working consistency with a muller on a smooth -slab (be sure that the ink on the roller is evenly distributed), after -wiping the plate carefully with a soft, damp cloth, proceed to ink up -the image slowly and carefully; then, when all the ink possible has -adhered to the image, take the glue roller and apply it three or four -times, which will clear the image wonderfully. Now put the mask in -position—either a cut-out, or four narrow strips of bank-post coated -with gold size and oil, and then dried—then put a piece of mat enamel -paper in position, then a piece of common printing paper on top, then a -piece of blanket; lower the tympan, run in the bed, and press, and, if -the pressure is not too much, the prints will be just as good; but, if -too much pressure be used, the paper will be creased and spoiled, and -the collotype image is in danger of being cut. - - -|178| - -CHAPTER V. - -THE NEW HOME PRINTING PROCESS. - -There is a method of making reproductions from photographs without any -photographing process further than that required to supply the print. -Any good photograph with a matt surface may be traced over with the -ink supplied for the purpose by the inventor of the process, or with -the ordinary lithographic autographic ink, which comes in sticks like -India-ink, and then the superfluous portions faded away (or not) as -directed on a preceding page. From that or from a crayon sketch, music, -a written letter, plans, or circulars, in fact, from anything written -with the proper ink with a pen or printed, reproductions may be made. -The principal appliances needed are the “Universal Copying Machine” and -its accessories. - -[Illustration: Fig. 23.] - -Where the results desired need not be of as high a grade as those made -by the Collotype processes, or where there is not time to make a zinc -etching, this method will serve a good purpose and produce satisfactory -results. The zinc plates used for etching will serve to hold the -transfers. The methods for cleaning the plates, already given, will -serve here also. The machine should be securely fastened to a table and -_the bearings must be kept well oiled_. - -Write, draw, or trace the original with a steel pen and the ink, on -well calendered paper, not too thick. For drawing, a fine pen is the -best. Then lay it, written side up, in a shallow dish, cover the paper -with the transfer solution, leave it from four to five minutes. If the -writing is several days old, leave it longer—about ten minutes. Lay it -between blotting paper and dry gently by rubbing with the hand or a -cloth. Then lay it, written side down, upon the polished plate, pass -it from four to six times under the iron roller, having first placed -a pasteboard over it. To prevent slipping, it is well to cover the -original with a sheet of blotting paper before putting the pasteboard -|179| over it. If you are not sure your press is screwed up evenly, -run the plate through two or three times, then turn it end for end and -pass it through as many times the other way. - -[Illustration] - -Place upon the small distributing roller as much printer’s ink as will -go upon the point of a knife, then holding the handle with the left -hand, press it upon the inking roller, and turn the crank, moving -the distributing roller from side to side, until the ink is evenly -distributed. - -See that the rollers are an equal distance apart at each end, so as to -print evenly. The original is now carefully removed. - -After washing the plate gently with a sponge and water and drying it, -also gently, with a clean cloth, rub the whole printed or written side -of the plate, by means of a cloth or sponge, with mixture No. 1, not -pouring the mixture directly upon the writing, but upon an unprinted -place upon the surface and rubbing over the whole plate. Wash off -immediately with sponge and water, and dry gently; then pour about -twenty drops of No. 2 upon the plate, not directly upon the print, and -rub over the whole surface, so that there is a thin coating of it over -the whole surface. This prevents the ink from sticking to the part of -the plate not covered with writing or print. If there is too much, the -paper of the copies will be yellow, and the negative may be injured. - -Now lay the plate upon the pasteboard and pass it under the inking -roller (the pressure does not need to be strong); it falls before -the iron roller; place a sheet of clean paper upon the negative, lay -a pasteboard over it, and pass it under the roller. For the first -impression it is well to pass it under several times, until the -negative comes out clearly and distinctly. From time to time, after -every ten or twelve impressions, apply No. 2; if the paper used for -printing is very coarse or porous, it may be necessary to apply No. 2 -oftener. - -As soon as the impressions become faint, apply a little more ink in the -manner described. After applying fresh ink, apply No. 2. Only when too -much ink is put on or unevenly distributed, or when the plate is not -covered with the thin coating of No. 2, or not properly cleaned, can -the negative or plate become soiled. If this should happen from any of -these causes, remove the spots carefully by means of a cloth wet with -preparation No. 2. - -If the ink hardens on the rollers remove it with lye or washing soda. - -If you wish to interrupt the work, the plate must be washed with a wet -sponge, to remove the preparation, and then dried with a cloth. On -using again, apply No. 2, as before. If the plate has not been used for -several days, apply both No. 1 and No. 2. Do not use woollen cloths. - -The mixtures No. 1 and No. 2 are supplied with the press. |180| - -Thus it will be seen that photographs may be reproduced by many -processes and in quantities to accommodate all sorts of demands. As an -averment of what the future holds, our book is brought to a close by -the following quotation from a recent issue of a daily newspaper: - -“Some time ago the _Evening Post_ gave an account of a new process -by which books were being reproduced in this country directly from -photographic plates, and it was said that the field for such business -would probably grow in proportion to the ease and certainty with which -this kind of work could be done. Under this process the most important -work issued so far has been seventeen volumes of the _Encyclopædia -Britannica_, this production being sold at half the price asked for an -American reprint already in the market, and at one-third of the price -of the imported book. In order to make this reproduction, the sheets of -the English volume are carefully photographed, and the glass negative -placed over a thick sheet of specially prepared gelatine and exposed -to the sun. Wherever the dark film upon the glass negative prevents -the light from reaching the surface of the gelatine, this substance -remains insoluble in water. Wherever the light penetrates, the gelatine -undergoes a chemical change which makes it soluble. After an exposure -to the sun or electric light for some minutes, the gelatine sheet is -washed with water and the result is a plate in relief, every black -line upon the glass negative being in high relief, and everything else -washing away under the sponge. - -“Until the last few years, it had been very difficult to get this -relief sufficient to print from, but by improvements in the process -effected by a number of different inventors, this result has been -obtained. The gelatine sheet having been hardened, an electrotype is -made from it which is put into the printing press. Owing to chance, the -gelatine sheet itself was used one day for printing from directly, and -it was found that a larger number of good copies could be made from the -gelatine direct than from the hardest electrotype. The only drawback -to the use of the gelatine plate itself in the printing press is its -liability to crack, for no reason that has as yet been discovered. If -some way is found of making the gelatine plate durable, it would be -used entirely in place of an electrotype, as it costs almost nothing -and can be made quicker than an electrotype.” - -The way has been “found” and zinc etching is doing the work. - -Finally, the essays of John Burnet, “On the Education of the Eye,” “On -Composition,” and “On Light and Shade,” copies of which are hard to get -for $100, have recently been reproduced by one of the processes given -in this book, full size, and is sold at $4.00. There is a great future -ahead for all process work. - - - - -|181| - -INDEX. - - - Acid, lateral action of the, 80 - - Acids, on the use of, 100 - - Actinometer, to make an, 107 - - Air brush, grain with the, 100 - - Albumen, coating the zinc plate with sensitive, 41 - ― etching in half tone, 69 - ― printing on the zinc in, 45 - - Albumenized zinc plate, inking the, 46 - - Albumenizing the glass plate, 21 - - Alcohol lamp, the, 98 - - All sources, hints from, 94 - - Apparatus etching, 97 - ― for printing upon zinc, 39 - - Appliances for making negatives, 9 - - As to the drawing, 94 - - Austrian method, etching on, 84 - ― middle etching, 87 - - Bath, the nitrate of silver, 12, 16, 27 - - Beer, preliminary coating of, 164, 170 - - Bitumen, printing on zinc in, 48 - ― etching in half tone, 70 - ― image on zinc, developing the, 50 - ― solution, to make the, 48 - - Black process, Colas’s, 109 - - Blackening in with a sponge, 78 - - Block, printing from the half tone, 72 - - Board, the developing, 141 - - Box, the best drying, 99 - - Bridge, the calibre, 93 - - Calibre-bridge, the, 93 - - Camera, the enlarging, 67 - - Carbon printing, 106 - ― tissue for reproductions, 32 - - Chiseling illustrated, 90 - - Clean etching, 91 - - Clearing solution, the, 18 - ― the glass, 21 - - Coating the zinc plate with sensitive albumen, 41 - - Colas’s black process, 109 - - Collodion process, the wet, 11 - ― film, protecting the, 20 - ― ― stripping, 34 - - Collotype process, the, 163 - ― ― sensitizing solution for, 164 - ― film, exposure at the back of the, 166 - ― ― exposure of the, 165 - ― operations, the, 167 - ― plate, printing from the, 171 - ― ― the finished, 67 - ― process, drying oven for the, 167, 174 - - Copper, mordants for, 112 - ― photo-engraving on, 119 - ― ― in line, 119 - ― relief, mordants for, 113 - ― solution, etching with sulphate of, 103 - - Damping fluids for collotype printing, 173 - - Dark-room, the, 25 - - Deep etching, 89 - - Developer for wet plates, 24 - ― for gelatine dry plates, 30 - - Developing the albumen image on the zinc plate, 42 - ― the bitumen image on the zinc plate, 50 - ― the paper transfer, 138 - - Developing-board, the, 141 - - Difference in processes, the, 117 - - Direct transfers to zinc, 51 - - Drawing, transfer of the, 83 - ― as to the, 94 - ― treatment of the, 73 - - Drawings, Colas’s process for reproducing, 109 - ― for photo-engraving, 51, 73 - ― the reversal of, 96 - - Dry plates in photo-engraving, 29 - - Drying-box, the best, 99 - - Drying oven for the collotype process, 167, 174 - ― the zinc plate, 42 - - Dusting-box, the, 124 - - Dusting sieve, 98 - ― the transfers, 54 - - Electrotype methods for half-tone intaglios, 127 - - Engraving, photo-, in half tone, 63 - - Enlarging camera, the, 68 - - Etching apparatus, 97 - ― clean, 91 - ― cleaning the, with a scraper, 88 - ― deep, 89 - ― ― illustrated, 90 - ― finishing and mounting the, 92 - ― fluids for collotype prints, 173 - ― galvanic process of, 101 - ― in half-tone (albumen), 69 - ― ― ― (bitumen), 70 - ― in relief, high, 104 - ― intermediate treatment, 79 - ― line transfers, 55 - ― manipulations of the process of, 93 - ― middle, Austrian method, 87 - ― ― and deep, illustrated, 88 - ― mordants for, 109 - ― ― for electric, 113 - ― ― for relief, 113 - ― ― for tint, 113 - ― ― for zinc, 115 - ― on copper, 121 - ― order of the manipulations, 86 - ― round, 88 - ― the Austrian method, 84 - ― ― illustrated, 88 - ― the first zinc, 57 - ― the French method of, 76, 80 - ― the second zinc, 58 - ― with sulphate of copper solution, 103 - ― zincographic, 115 - - Exposed zinc, inking the, 44 - - Exposure and timing, 43 - ― of the collotype film, 166 - ― ― ― ― ― at the back, 166 - - Fading out the photograph, 96 - - Faults in strengthening, 78 - - Finishing and mounting the etching, 92 - - Fixing, solution, the, 18 - - Fluids, damping, for collotype printing, 173 - ― etching, for collotype printing, 173 - - French method of etching, 76, 80 - - Further treatment of the transfers, 16 - - Galvanic process for etching, 102 - - Gelatine dry plates in photo-engraving, 29 - - Gillotage (Gillot’s process), 101 - - Glass, albumenizing the, 22 - ― plate, the, 21 - ― silvering the, for mirrors, 36 - - Grain on a negative, to produce, 100 - - Grained negatives, making, 65 - ― ― transparencies for, 66 - - Graining the zinc plate, 40 - - Half-tone photo-engraving, 63 - ― ― etching in (albumen), 69 - ― ― ― ― (bitumen), 70 - ― ― block, printing from the, 72 - ― ― intaglios, 122, 124 - ― photo-lithography in, 143 - - Heliotype process, the, 152 - ― skin, the, 160 - ― ― printing the, 158 - ― ― mounting on pewter, 159 - - High etching in relief, 104 - ― ― dusting-box for, 124 - ― ― electrotype method for, 127 - - Hints from all sources, 94 - - Husband’s papyrotint process, 147 - - Ink for transfers, hard, 55 - - Inking the exposed zinc, 44 - ― transfers, 54 - - Ink-photos, 144 - - Intaglios, half-tone, 122, 124 - ― dusting-box for, 124 - ― electrotype methods for, 127 - - Intensifier, the, 18 - - Lamp, the alcohol, 99 - - Lateral action of the acid, 80 - - Line, photo-engraving in, 9 - ― ― on copper in, 119 - ― photo-lithography in, 128 - - Line transfers, etching, 56 - ― ― ink for, 56 - - Making grained negatives, 65 - - Manipulations in etching, order of the, 86 - - Manipulations of the etching process, 93 - - Manipulations, photographic, 24 - - Mask, the, 156 - - Middle etching, Austrian method, 87 - ― ― French method, 80 - - Mirror, the reversing, 10, 35 - - Mordants for copper, 112 - ― for etching, 109 - - Mounting and finishing the etching, 92 - ― the cliché, before, 79 - ― the zinc etching, 61 - - Negative printing, 96 - ― ― to produce grain on a, 100 - ― transfer process, Toovey’s, 139 - ― washing, 19, 28 - - Negatives, appliances for making, 9 - ― making grained, 65 - ― screen for grained, 65 - ― the reproduction of, 31 - ― transparencies for grained, 66 - - Nitrate of silver bath, the, 12, 16 - - Oven for the collotype process, drying, 167, 174 - ― using the, 168 - - Paper transfers, 132, 136 - ― ― developing the, 138 - ― ― ― ― sensitizing solution for, 137 - - Papyrotint process, Husband’s, 147 - - Pewter plate, mounting on the, 159 - ― ― the, 156 - - Photo-engraving, half tone, 63 - - Photo-engraving in line, 9 - - Photograph, fading out the, 96 - - Photographic manipulations, 24 - ― negatives, appliances for making, 9 - - Photo-inks, 144 - - Photo-lithographic transfers, to develop, 140 - - Photo-lithography in half-tone, 143 - ― in line, 129 - - Plate, graining the zinc, 40 - ― the glass, 21 - ― the pewter, 156 - - Polishing the zinc, 39 - - Pomatum wax, how to make, 81 - - Positives for negative reproduction, 31 - - Preparation of the rollers, 154 - - Preparing the printing press, 176 - - Printing, carbon, 106 - ― collographic, 172 - ― ― damping fluids for, 173 - ― ― etching fluids for, 173 - - Printing frame, the, 43 - - Printing from the collotype plate, 171 - ― from the half-tone block, 72 - ― press, preparing etchings for, 102 - ― ― preparing the, 176 - ― process, the new home, 178 - ― the heliotype skin, 160 - ― upon zinc, apparatus for, 39 - ― ― ― in albumen, 45 - ― ― ― in bitumen, 48 - - Processes, the difference in, 117 - - Process, the collotype, 163 - ― the heliotype, 152 - ― the wet collodion, 11 - - Protecting the collodion film, 20 - - Relief, high etching in, 104 - - Reproduction of drawings, Colas’s process, 109 - - Reproduction of negatives, the, 31 - ― with carbon positive, 32 - - Retrospective, half-tone photo-engraving, 63 - - Reversal of the drawings, 96 - - Reversing mirror, the, 10, 35 - - Rollers, the, 153 - ― preparation of the, 154 - - Room, the dark-, 25 - - Round etching, 90 - - Running of a workshop, 104 - - Screen for grained negatives, the, 65 - - Sensitometer, to make a, 107 - - Sensitizing solution, a good, 105 - - Sensitizing solution for paper transfers, 132 - ― ― for the collotype process, 165 - - Sieve, dusting, 98 - - Silver bath, the nitrate of, 12, 16 - - Silvering the glass (for mirrors), 26 - - Skin, the heliotype, 156 - ― mounting on pewter, 159 - ― printing from the heliotype, 160 - ― printing the heliotype, 158 - - Solution, clearing the, 18 - ― developing the, 17 - ― fixing the, 18 - ― intensifying the, 18 - - Sources, hints from all, 94 - - Stereotyping, zinc etching by, 102 - - Strengthening, faults in, 78 - ― French process, 82 - - Stripping collodion films, 34 - - Sulphate of copper solution, etching with, 103 - - Table, the washing, 98 - - Timing and exposure, 43 - - Toovey’s negative transfer process, 139 - - Transfer process, Toovey’s negative, 139 - ― and treatment of the drawing, 73 - ― of the drawing, 73, 83 - ― paper, 132, 136 - - Transfers, developing the, 138 - ― dusting the, 54 - ― etching line, 55 - ― further treatment of the, 76 - ― ink for line, 56 - ― inking the, 54 - ― photo-litho, 140 - ― to develop, 140 - - Transfers to zinc, direct, 51 - - Transparencies for grained negatives, 66 - - Transparencies, how to make, 30 - - Transparent positive, making the, 120 - ― ― sensitizing the, 137 - - Treatment before mounting, 78 - - Washing, Austrian process for, 85 - ― French process for, 83 - - Washing table, the, 98 - ― the negative, 19 - - Wax pomatum, how to make, 81 - - Whirler, the, 42 - - Work-shop, running of the, 104 - - Wrinkles and dodges, 105 - - Zinc, apparatus for printing upon, 39 - ― ― direct transfers to, 51 - ― etching the first, 57 - ― ― by galvanic means, 102 - ― ― by stereotyping, 102 - ― ― mounting the, 61 - ― ― the second, 58 - ― ― the manipulations of, 93 - ― in albumen, printing on the, 45 - ― in bitumen, printing on the, 48 - ― inking the exposed, 44 - ― plate, developing the albumen image on the, 47 - ― ― ― the bitumen image on the, 50 - ― ― ― inking the, 54 - ― ― graining the, 40 - ― ― coating with sensitive albumen, 41 - ― ― drying the, 42 - ― ― whirling the, 42 - ― ― inking the albumenized, 46 - ― ― the, to coat with bitumen, 49 - ― polishing the, 39 - ― preparing on the press, 102 - - Zincographic etching, 115 - ― printing press, the, 62 - - - - -ADVERTISEMENTS - - -[Illustration: E. & H. T. ANTHONY & CO. - -No. 591 Broadway, New York. - -MANUFACTURERS AND IMPORTERS OF Photographic Instruments and Supplies - -SOLE PROPRIETORS OF THE SATCHEL DETECTIVE, SCHMID DETECTIVE, CLIMAX -DETECTIVE, CAMERAS FAIRY, NOVEL, AND “THE PHANTOM CAMERA,” the Champion -Light Weight of the World. - -USE ANTHONY’S CELEBRATED “E A” TRADE-MARK CHEMICALS. SUPPLIED BY ALL -DEALERS. - -BROMIDE! BROMIDE! BROMIDE! - -ANTHONY’S Patent Reliable Bromide Paper FOR CONTACT PRINTING AND -ENLARGEMENTS. Rapid for Artificial Light. Slow for Daylight. - -SEND FOR ILLUSTRATED CATALOGUE.] - -[Illustration: Fred’k W. Devoe. James F. Drummond. J. Seaver Page. - -F. W. Devoe & Co. Cor. Fulton and William Streets, New York. - -Manufacturers of ARTISTS’ MATERIALS, DRAWING INSTRUMENTS, FINE BRUSHES, -READY MIXED PAINTS AND VARNISHES. - -Fine Dry Colors for Lithographers. White and Tinted Hand-made Papers, -Ingres, Crayon and Torchon, Gelatine Paper, Magnifying and Diminishing -Glasses, Grained Papers for Process Drawing, Crayons, India Ink, -Roulettes, etc., “Imperishable” Paste for Mounting Photographs. - -SUPPLIES FOR OIL PAINTING, WATER COLOR PAINTING, SKETCHING, PORCELAIN -AND CHINA PAINTING, PASTEL PAINTING, MINIATURE PAINTING, CRAYON AND -LEAD PENCIL DRAWING, ETCHING, CHROMO PHOTOGRAPHY, TAPESTRY PAINTING, -TEXTILE DESIGNING, MODELING IN WAX AND CLAY, LUSTRE PAINTING, PEN AND -INK DRAWING, REPOUSSÉ WORK, FRESCO AND SCENE PAINTING, MAKING WAX -FLOWERS AND FRUIT, ETC. ETC. - -COFFIN, DEVOE & CO., Chicago, Ill. - -F. W. DEVOE & CO., Fulton St. cor. William, New York. - -Catalogues of our various departments to dealers, on application.] - -[Illustration: THE Huber Rotary Zincographic Press. - -This press was designed and is now in successful operation for printing -from zinc plates the kind of work hitherto produced from stone in the -lithographic press; and by reason of its continuous rotation many more -impressions per hour can be produced than by the stone method. Colors -are printed by it in perfect register and with no loss of brilliancy or -change of the color. The advantages of the use of zinc plates are fully -set forth in our circular No. 1, “Zincography” which will be mailed to -lithographers on receipt of their address. - -To purchasers of the zincographic press, we give full instructions in -zincography, and the chemical nature of the various preparations, etc., -without extra charge. - -Harris & Jones, Sole Selling Agents, No. 31 Pearl Street, Providence, -R. I.] - -[Illustration: A. M. Collins Mfg. Co. No. 527 Arch Street PHILADELPHIA. - -Makers of all kinds of Cards required by Photographers.] - -[Illustration: ALLEN BROTHERS, DETROIT, MICH., Are Sole Agents for this -Continent, for The Best Lenses in the World As well as the Cheapest, -THE SUTER LENS. - -Price Lists and Testimonials Sent on Application. - -A complete supply in stock of every requisite for PHOTOGRAPHY, -PHOTO-ENGRAVING, PHOTO-ETCHING, and PHOTO-LITHOGRAPHY.] - -[Illustration: CARBUTT’S DRY PLATES FOR ALL KINDS OF Photo-Mechanical -Reproduction. - -STRIPPING PLATES for Photo-Gelatine Printing, Sensitometer 22, kept in -stock, and made to order more or less sensitive when desired. - -STRIPPING PLATES, giving great contrast, for the Zinc-Etching Process, -Sensitometer 14 to 16. - -PROCESS PLATE B, 14 to 16, capable of giving clear glass lines and -great density in ground, for Photo-Engravers. - -FOR COPYING COLORS - -CARBUTT’S ORTHOCHROMATIC PLATES will be found the greatest improvement -in Dry Plate making. They are kept in stock of Normal Sensitometer 22, -but made to order more or less sensitive as may be required. They are -used extensively by F. E. Ives, Philadelphia, and the Photo-Gravure -Co., New York. - -“If I may venture the prediction, I think the history of photography -for the next decade will be the history of orthochromatic work. Surely -next to the production of the colors themselves, there is nothing to be -desired so much as the rendering of the true values of these colors. I -place the orthochromatic negative as the highest point yet attained in -negative making, and as constituting the outcome to-day of that germ -which was brought into being nearly one hundred years ago.”—Extract -from Ernest Edwards’ article on “The Art of Making Photo-Gravures.” - -“With reference to the Orthochromatic Plates. The Photo-Gravure Co. -is greatly pleased with its success in the use of your plates of -this description. They enable us to obtain results which otherwise -would be impossible, and to do work that otherwise we should have -to decline, placing a great power in the hands of an intelligent -operator....”—Ernest Edwards, for Photo-Gravure Co., Brooklyn, February -13, 1888. - -CARBUTT’S DRY PLATES can be obtained of all Dealers in Photo Materials, -or direct from the KEYSTONE DRY PLATE WORKS, Wayne Junction, John -Carbutt, Proprietor. PHILADELPHIA, PA. - -SEND FOR PRICE LIST] - -[Illustration: THE LATEST NOVELTY OUT. - -The New Magic Vignetter, (Illustration: Patented May 31st, 1887.) For -producing the Popular Black Background or Ebony Photographs. - -Endorsed and in use by the Leading Photographers of the United States. - -No more trouble or expense than making plain photographs. - -It is easily attached to any camera by fastening it on the inside of -the diaphragm of the box (as shown in the cut). - -The opening can be adjusted to the proper size by simply turning the -thumb-screw. Focus and expose as usual. Every one guaranteed. - -PRICE, EACH, $8.00. - -For sale by all dealers in Photographic Goods. - -Sample photographs of work done with it furnished on application to - -H. A. HYATT, Sole Agent, Dealer in Photo Supplies of Every Description. -N. E. Cor. Eighth and Locust Streets, ST. LOUIS, MO.] - -[Illustration: THE AIR BRUSH. - -(Illustration: Medals: American Institute 1884, Franklin Institute -1885, Franklin Institute 1887.) - -The Brush applies dilute liquid pigment by a jet of air. To -photographers producing large work, its use is especially recommended -in place of crayon, and for water colors. With equal skill on the part -of the artist, the work is accomplished with far more elegance, and -with wonderful saving of time. The Brush will be sent upon trial. - -The Air Brush has been found one of the most useful helpers in Process -Engraving that has ever been discovered. See instructions given in this -book. - -For full description, terms, and any particulars desired, address, AIR -BRUSH MANUFACTURING CO. - -69 Nassau Street, ROCKFORD, ILL.] - -[Illustration: VIOLET Lightning Flash Compound, (BRUTUM FULMEN.) - -Pictures Made in the Darkness. - -Do not waste DRY PLATES trying to make NEGATIVES AT NIGHT WITH CHEAP, -FROUZY MIXTURES. - -Use the best. Sure Pop. No Animal Charcoal. No Chlorate of Potash. No -Acid. VIOLET LIGHTNING FLASH, the most powerful light under the sun. - -Price, Per Bottle, 75 Cents. - -Write for particulars and catalogue of all Photographic Materials. -BUCHANAN, BROMLEY & CO., Manufacturers, PHILADELPHIA.] - -[Illustration: THE GUNDLACH PHOTOGRAPHIC LENSES MANUFACTURED BY THE -GUNDLACH OPTICAL CO., ROCHESTER, N. Y. - -ARE THE BEST IN THE WORLD FOR ALL KINDS OF Photo-Mechanical Work. - -Send for Descriptive Price List. - -For sale by dealers in Photo. Goods.] - -[Illustration: THE UNIVERSAL COPYING MACHINE - -COPIES PRINT, WRITING, TYPE-WRITING, WOOD-CUTS, LITHOGRAPHS, CRAYON -DRAWINGS, PRINTED OR WRITTEN MUSIC, ETC. - -The original is written with our copying ink or with our ribbon, and -then, by a simple and sure process, transferred to a plate, from which -any number of copies can be taken. Print is transferred to the plate -without spoiling the original, and then copied like writing. - -A great number of copies can be made from one original. As printer’s -ink is used, all impressions are alike clear and legible, and can be of -any color desired. - -The negitive can be kept for years, or it can be removed in a minute, -and the plate used over and over again. - -This process has been awarded medals at recent exhibitions in different -European cities, and is patented in Great Britain, Germany, France, -Belgium and the United States. - -It is simple, cleanly, not liable to get out of order; can be used in -any climate, and is not affected by the weather. - -Its importance to men of business, teachers in day and Sunday schools, -photographers, musicians, and others, is obvious. - -The samples sent out are printed by ourselves, and on the Universal -Copying Machine. - -Price of machine with outfit, plate 9 × 13-1/2 inches, legal-cap size, -$20.00. Price, with process to copy print, etc., $5.00 extra. Ribbons -for different type-writers, $1.00 each. - -Larger machines can be furnished, if desired; but this is a very -convenient size. - -Samples of work sent free of charge. - -UNIVERSAL COPYING MACHINE CO., J. R. PALEN, Treasurer. No. 1343 Arch -Street, Philadelphia.] - -[Illustration: THE FAVORITE Photo Supply House AT LOUISVILLE, KY. W. D. -Gatchel, Agt. - -WE CARRY IN STOCK A VERY LARGE SUPPLY OF - -The Choicest Apparatus, Best Dry Plates, Pure Photo. Chemicals, Best -Albumen Paper, Collins’ Card Stock, Picture Frames, and Mats. - -ALL OF WHICH ARE SOLD AT A REASONABLE PROFIT. - -Our trade is constantly growing, without noise or advertising. Our -customers tell of their satisfaction to their friends, and that is how -it is done. We have goods for all, and invite your orders.] - -[Illustration: Boston Photogravure Company. - -27 Boylston St. Boston. - -Gelatine Printing (Phototype), Photo-engraving, Photo-lithography, -Photographing on Wood. - -Our Phototypes can be seen in the finest Art Books ever issued in this -country. - -Whoever uses Photographs in quantity can save a large per cent. by our -Gelatine Printing. - -Permanent ink in any color on any kind of paper. - -REPRESENTED IN NEW YORK BY Brandon Moses, 52 Beaver St.] - -[Illustration: WILSON-HOOD-CHEYNEY CO. LIMITED. - -JOHN G. HOOD, CHAIRMAN. - -WM. D. H. WILSON, TREASURER. - -JOS. P. CHEYNEY, SECRETARY. - -Sole U. S. Agts for the ROSS LENS - -Which has no equal for producing Negatives for Photo-Engraving, -Etching, and Lithography. - -DEALERS IN PHOTO. SUPPLIES. - -No. 910 ARCH STREET, PHILADELPHIA.] - -[Illustration: A. WILD, - -GENERAL AGENT FOR Prof. J. Husniks PHOTO-LITHOGRAPHIC TRANSFER PAPER - -134 SENECA ST BUFFALO N-Y. - -Send for Estimates and further Information - -THE BEST PROCESS IN THE WORLD FOR REPRODUCTIONS OF ALL KINDS OF LINE -DRAWING, STEEL PRINTS AND LITHOGRAPHS. FURNISHES TRANSFER PRINTS TO -LITHOGRAPHERS OF ALL CLASSES OF LINE WORK, ALSO FROM WASH DRAWINGS AND -PHOTOGRAPHS AT THE LOWEST PRICES.] - -[Illustration: FUCHS & LANG NEW YORK AND CHICAGO. - -MANUFACTURERS OF ALL MATERIALS FOR THE ZINC ETCHING PROCESS. - -PRACTICAL INSTRUCTOR OF Photo-Engraving and Zinc Etching PROCESSES. - -COMPRISING A FULL EXPLANATION OF DRAWING, PHOTOGRAPHY, WASH-OUT, -SWELLED-GELATINE, AND ZINC-ETCHING PROCESSES. - -BY ALEX. F. W. LESLIE. - -PUBLISHED BY FUCHS & LANG, 29 Warren St., New York. 79 Dearborn St., -Chicago. Factory: 97–101 N. Third St., Brooklyn, E. D., N. Y. - -SECOND ENLARGED AND REVISED EDITION. - -PRICE, $1.00.] - -[Illustration: THE INLAND PRINTER IS THE UNIVERSALLY RECOGNIZED - -Leading Trade Journal in the Printing Industry. - -No. 183 MONROE STREET, CHICAGO. - -As an Advertising Medium to Reach the Trade it has no Equal. AS A -TECHNICAL INSTRUCTIVE JOURNAL It is Indispensable alike to Employer and -Employe. - -Containing each month from 30 to 40 pages of Reading Matter. - -Its Pages teem with Articles of Interest; It Advocates no Crotchets; -Supports no Cliques; Is Fearless in Attacking Abuses, and Seeks the -Greatest Good to the Greatest Number. - -Subscription, $2.00 per Year. Single Copy, 20 Cents. - -NO FREE SAMPLE COPIES SENT. - -To stimulate interest in the Best Printers’ Journal published, we make -this offer: Any one sending us five yearly subscriptions, we will place -his name on our subscription list for one year; to any one sending us -ten yearly subscriptions, we will present a bound copy of either Vol. -II., III., or IV., and pro rata. - -The Inland Printer Co., Publishers, Chicago.] - -[Illustration: The Photo-Gravure Company - -No 853 Broadway New York - -SOME OPINIONS OF THE PRESS. - -New York Evening Post. - -“As a work of pure illustration it is unique. - -“Unequalled by any similar collection produced on this side of the -Atlantic. For the Photo-Gravures not even this qualification need be -made. - -“Several of these are gems of their kind, and will surprise even -photographers who are not fully conversant with the recent advance -in that branch of engraving, in which the Photo Gravure Co. stands -unsurpassed now, when it is a question of dealing with negatives from -nature.” - -Philadelphia Sunday-School Times. - -“The pictures like those of The Art Review, are the work of the -Photo-Gravure Company, which has here produced a distinctly American -art work unexcelled in the present season.” - -New York Mail and Express. - -“Reproduced by the Photo-Gravure Company in a most admirable manner. -They are not to be described, however, for there is a charm about them, -interfused in their soft lights and tender shadows, which evades words.” - -Philadelphia Times. - -“One of unusual beauty. - -“The execution of nearly all of them is admirable.” - -The Nation. - -“Our publishers have hardly begun to realize the resources which -this process offers for the decoration of books, with a very slight -enhancement of the cost.” - -New York Independent. - -“These illustrations are reproduced in deliciously soft tones by the -Photo-Gravure Company, of New York.” - -The Evening Transcript, Boston. - -“A volume of unusual beauty. - -“Most of the illustrations are perfect gems.” - -The Public Ledger, Philadelphia. - -“The result is an art production by chemical and mechanical processes, -that is in its way comparable to the best work of the engraver -or etcher. It is something far beyond the ordinary work of the -photographer, and may be considered the highest development of his art.” - -The New York Commercial. - -“Admirably reproduced by Photo-Gravure.” - -The Commercial Gazette. - -“Here again, the advance of the American engraver’s art is strikingly -apparent.” - -The Literary World. - -“We wish always to be sparing in the use of superlatives, and guarded -in the use of strong language, and to preserve carefully what -reputation we have for a conservative and temperate judgment; but -restraint is hard to bear in speaking out our minds about the work -which, at the present writing, lies open on the editorial table. - -“The Photo-Gravures introduced here and there by way of border -decorations are exquisite, and the occasional vignettes dropped upon -the corner of a larger plate introduce a charming irregularity and -variety.” - -The Susquehanna Evening Transcript. - -“The illustrations are the finest we ever saw in a newspaper -supplement.” - -PHOTO-LITHOGRAPHIC AND PHOTO-MECHANICAL PRINTING OF EVERY DESCRIPTION. - -Catalogues of our Publications on application. Estimates of work -cheerfully furnished and correspondence solicited. - -Portfolio of specimens, worth $10, containing examples of all our -processes, forwarded on receipt of price, $1.00.] - -[Illustration: GET THE BEST PHOTOGRAPHIC BOOKS. - -THE WHOLE ART IN TWO BOOKS. - -Wilson’s Quarter Century in Photography. - -THE LARGEST AND BEST PHOTOGRAPHIC INSTRUCTION BOOK EVER ISSUED. - -By EDWARD L. WILSON, - -Editor of the “Philadelphia Photographer,” Author of “Wilson’s -Photographics,” etc. - -$4.00. “The best in the English language.”—Photographic News. $4.00. - -Chapter I. The History of Photography. II. The Theory of Photography. -III. Light. IV. The Camera. V. About Lenses. VI. The Diaphragm, or -Stop. VII. Glass-house Construction. VIII. Under the Skylight. IX. The -Application of Art Principles. X. Outdoor Operations. XI. Exposure, -or the Question of Time. XII. Concerning Chemicals. XIII. Dark-room -Contrivances. XIV. Negative-making—“Wet.” XV. Negative-making—“Dry.” -XVI. Negative-making—“Paper and Film.” XVII. Retouching and -Doctoring the Negative. XVIII. Printing on Albumenized Paper. XIX. -Printing—Drawbacks and Defects; Causes and Remedies. XX. Printing-room -Particulars. XXI. Peculiar Printing Processess. XXII. Color-Sensitive -Photography—Isochromatic—Orthochromatic. XXIII. Photo-engraving. XXIV. -Lantern Slides and Transparencies. - -528 Pages—386 Illustrations. With a Complete, Classified Index. - -Quarter Century is equivalent to several volumes in one. It contains -the best practical points on photography that have been published -during the past 25 years, by over 250 well-known workers and writers -in our art, all arranged with great care—clipped of all superfluous -matter—and condensed into a satisfactory, common-sense instruction -book, the usefulness of which will never change or wear out. - -$4.00. Wilson’s Photographics. $4.00. - -By EDWARD L. WILSON, - -Editor of the “Philadelphia Photographer,” Author of “Wilson’s Quarter -Century in Photography,” etc. - -Over 6000 copies sold. 1000 Testimonials. Every Artist needs it. -Entirely different from Quarter Century. - -A. Treatment of the Subject. B and C. The Needful Apparatus. D. The -Dark-room. E. Preparation of the Glass. F. Chemicals and Solutions. -G. The Manipulations. H. Manipulatory Miseries. I. Retouching the -Negative. J. The Glass Studio. K. Accessories and Light. L. Managing -the Model. M. Printing on Albumen Paper. N. Printing on Plain Paper. -O. General Remarks on Printing. P. Printing on Various Surfaces. Q. -Printing Perplexities. R. Art in Printing. S. Mounting and Finishing. -T. Photography Outside. U. Bromo-Gelatine Emulsion Work. V. Vogel’s -Collodion Emulsion. W. Enlargements and Lantern Slides. X. Phototypes, -Platinotypes, and Collodion Transfers. Y. Wastes and their Worth. Z. -Metrical Measuring &. Concluding Confab—Appendix. A full, careful Index. - -110 Illustrations. 2 full-page plates. - -Burnet’s Art Essays. - -A curiosity, as well as a valuable work. Three in one: Essay on the -Education of the Eye; Essay on Light and Shade; Essay on Composition. -About 140 illustrations, all reproduced by the Heliotype process, -taught in this book. $4.00. Originals are scarce at $100.00. - -I also publish the oldest and best PHOTOGRAPHIC MAGAZINE twice a month. -Every number accompanied by a full-page lovely photo study. Sample Copy -Free. Every person, firm, and family interested in the beautiful should -have it. - -“Should be scattered broadcast over the whole land.”—Abell & Son, -Oregon. “Is the boon companion of the country photographer.”—H. A. -Cudding, New York. “Always contains something of benefit to the -fraternity.”—C. P. McDannell, Pennsylvania. “Has come to me since 1864, -and I will not do without it”—J. R. Schorb, South Carolina. “I have had -it for nearly twenty years.”—C. E. Orr, Illinois. “Will continue to me -as long as it is conducted in the present excellent manner.”—James S. -Patterson, Tennessee. - -Subscribe Now. $5.00 a Year; $2.50 for Six Months; $1.25 for Three -Months; 30 Cents per copy. $1.00 Premium in books for a new subscriber -with your own. Circular Souvenir Free. - -EDWARD L. WILSON, 853 Broadway, New York.] - -[Illustration: A. WITTEMANN, Publisher and Printer for the Trade of -Souvenir Albums - -PHOTO VIEWS OF American Scenery, Cities, and Resorts. - -Nos. 58 and 60 Reade Street, NEW YORK. - -Correspondence with Photographers solicited.] - -[Illustration: THE ALBERTYPE CO. Nos. 58 and 60 Reade Street, NEW YORK. - -Photo-Mechanical Printing - -ILLUSTRATIVE. DECORATIVE. COMMERCIAL. - -REPRODUCTION OF - -Scenery, Architecture, Interiors, Portraits, Works of Art, Designs, -Engravings, Patterns, Machinery, Manufactures, and objects of all kinds. - -For Quickness, Accuracy, and Delicacy there is no superior to the -Albertype Process.] - - - - -TRANSCRIBER’S NOTE - -Original spelling and grammar are generally retained, with a few -exceptions noted below. A few missing full stops were supplied -silently. Original italics _looks like this_. The original page numbers -are shown like this: |97|. The original pagination is screwy. The -Introduction is on pp. xv–xvi, and then the next page is numbered -9. There are no pp. 1–8. Illustrations have been moved from within -paragraphs to between. Blank pages have been removed. Footnotes have -been moved from within paragraphs to between paragraphs. Ditto marks -have been removed, with text restructured as necessary to retain the -original meaning. Similarly, large curly brackets—used to combine -information on more than one line of text—have been removed. The -original Index employed white space to indicate words or phrases to be -regarded as repeated from the text line above. This edition employs -instead the character U+2015 HORIZONTAL BAR ―, one for each word to be -repeated. - -Page 36. The left double quotation mark has no mate, but is retained as -printed. - -Page 73. The phrase “sheet of Bristol paper and are of pressing board” -is retained as printed. - -Page 84. The second _at_ was removed from “strength of 2° Baumé at at a -temperature”. - -Page 103. Changed _zince_ to _zinc_, in “take the zince plate”. - -Page 134. Changed “throughly melted” to “thoroughly melted”. - -Page 140. Changed “with a a glue roller” to “with a glue roller”. - -Page 141. Changed “difcult to handle” to “difficult to handle”. - -Page 182, entry _Exposure_. Changed “timeing” to “timing”. Likewise, on -page 184, the entry _Timeing_ was changed to _Timing_. - - - - - - - - - - - - - - -End of the Project Gutenberg EBook of Photo-engraving, Photo-etching and -Photo-lithography in Line and Half, by W. T. 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