The Autotype Carbon Process

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English Pages 28 [19] Year 1908

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The Autotype Carbon Process

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NOTES ON

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The Autotype Carbon Process BY

A. C. BRAHAM, . F.R.P.S. Chief of the Technical Staff at The Au.totype Works. W'est Ealing.

~ ~ PUBLISHED BY

THE AUTOTYPE COMPANY,

74 New Oxford St., London·, (and West Ealing) . PRICE SIXPENCE.



FOREWORDS. ·

THE following chapters were originally published in the Australian Photo Review at Melbourne, and in Snap Shots at New York, in the hope of increasing the use of the Carbon process abroad. They are now issued m the home of carbon printing, with the wish to convince beginners that the process is as easy as it is desirable, and in the hope that they may be of assistance both to the beginner and the regular user in indicating the steps which most surely lead to success in working.

A. C. BRAHAM.

WEST EALING,

Marek, 1908.

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THE CARBON PROCESS. ---~~~---

CHAPTER !.-INTRODUCTION.

IT is strange that carbon printing should be neglected by many amateurs, who while willing to take great pains in the selection of subjects for camera work, and produce excellent negatives are then content to employ printing processes which are only a second best ; neglecting a process which will '' give a greater variety of effect than any other process or indeed than all the other printing processess combined.'' This comment, extracted from an editorial in the British Journal of Photography, certainly shows a high appreciation of the merits and advantages of carbon printing ; an appreciation which may however readily be substantiated. Should the subject represented be a Cathedral interior, various shades of black may be employed, Brown Black or Warm Black developed on slightly toned transfer paper giving a charming rendering of stonework; should the choir, or det~ils of stalls or other woodwork be represented, various browns, such as Cool Brown . or Sepia are more usually employed. Landscapes may be printed in blacks, ·browns, and greens,. of which colour several different tones are manufactured; in fact, a colour chart issued by the Autotype Company contains examples of thirty distinct standard colours, and even others. are made to meet special requirements.

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For those fortunateiy enough situated to be able to take snow scenes, Engraving Black (printed lightly) offers a means of rendering the range of gradation in snow, between a sunlit patch and the shadows in a drift not otherwise to be obtained. For sea-scapes, snap shots of yachts, studi~s of breakinO' waves, the . various greens and blues ranging ~ from Italia~ Green to Turquoise Blue will give a choice of · colours wide enough to satisfy the most exacting taste. -' In Portraiture, so called " .photographic tones " are readily obtained by using- Portrait Brown, Ruby Brown or Warm Sepia ; .many profes~ional photographers . not bound by convent10n, employ with great success, especially for portraits of ladies and children, Red Chalk and Terra Cotta, and occasionally even Bright Red or Carmine. . . Reproductions of paintings, drawings, etc., may be made in the pigments of the Artist's palette-hence the name '' AuT~TYPE,". which was first used by the. late Tom Taylor (som~time Ed1t?r of Punch, and art critic) to define reprod~ctions of .artist s work, made photographically, that is, w1th~ut the mtervention of another's eye or hand; the term ~as smce been ~xtended to includ~ any photograph produced m permanent pigments. · · ~y the choice of suitable transfer papers endless modifications of tone and texture may be obtained,' ranging from the extreme gloss of P. 0. P. (should such be desired) to the deep dead matt of a fine mezzotint engraving, and with an imperceptible grain or the roughest texture. · Who that ?W~~ photographs of t?ose "Loved long since and lost awhile, has .not had occas10n to lament the fading of so.me valued portr.a1t. ? and from a merely utilitarian point of v1~w what. folly_ 1t 1s to spend either time or money in workmg up, either m colour or monochrome on a base which will. probably become ~ellow and fade, dest;oying the values of bght and shade obtamed, and making what was a pleasing portrait only grotesque. For t~e credit of photography it is to be regretted that the pubbc do not always realise the risky nature of a ·worked up silv~r print, and insist that when they pay a certain or 1.mcertam number of guineas for artistic finishing, they shall

have a reasonable certainty that the result shall be permanent. This may be secured by employing carbon prints; the best makers of tissue being scrupulously careful to use only permanent pigments in the manufacture of their products, and to use papers that are least liable to change tone with age, for all papers, even the best, are subject to a slight but negligable change of tone. . The choice of a process is often decided by the question of cost, although economy should be rather a wise expenditJ.Ire of money . than merely a question of cheapness. In this respect, carbon is about on a par with silver printing because although the cost of tissue and transfer may be slightly above that of silver paper, there is no further incidental expense for toning solutions to be considered. Compared with the only other permanent process, platinum, carbon including tissue and transfer paper, will be found to be only half the price of platinum paper, taking the price from the current list of the leading firm making platinum paper. This extreme difference of price is partly accounted for by the. present high price of the metal platinum, but at all times carbon is far less costly. · Having dealt with the beauty and variety of the process, with its important advantage of permanency and its cost, I will proceed to.the practical details of manipulation, bearing in mind Dr. Johnson's phrase from the Introduction to his Dictionary, "Words are the daughters of earth, but things are the sons of heaven."

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CHAPTER II.-GENERAL PRINCIPLES.

THE practice of. carbon printing depends on the property of ~elatine, combined with bichromate of Potassium, becoming !~soluble when exposed to light. If carbon or any suitable p1gm~nt b~ incorporated with the gelatine, the insoluble gelatme will hold and imprison the colouring matter. If a sheet of paper which has been coated with gelatine mixed

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with pigment and bichromate and allowed to dry, be exposed to light under a negative, varying proportions of the gelatine will be rendered insoluble. Through the shadows of the negative where much light passes, much gelatine will consequently be .rendered insoluble-through the h~lf tones less light passes-less gelatine therefore becomes insoluble, through the highest lights of the negative practically no light passes, consequently the whole of the gelatine remains soluble. The image thus formed"in the tissue (as the coated paper is called) can now be revealed by dissolving and was:µ.ing away the remaining soluble gelatine and colouring matter. The formation of a carbon print is therefore analogous,, although exactly the reverse process, to making a wash drawing. In the case of a wash drawing we start with clean paper and by adding successive washes of colour build up the image-in the case of a carbon print we start with paper heavily coated with pigment, form an image by the action of light' and reveal it by washing away the superfluous colour that' hides it. Pioneers in carbon printing endeavoured to develop the image by immersion in hot water-but success was only obtained when it was recognised that the insoluble image ·was upon or on the upper portions of the pigment coating, the soluble portions being the lower parts or those in contact with the paper in which the coating was spread. The dissolving therefore must take place from the back, and, means were then sought to attach the printed tissue to a support. Various cements, among them India rubber solution were used; both tissue and support being coated with-the solution, allowed to partially dry and then passed in contact through the rolls of a copper-plate press. Under these conditions it is not surprising that carbon printing was regarded as for the few. Soon, however, the cementing of the tissue was abolished, transfer paper sold ready coated with insoluble gelatine, and the costly and cumbrous copper-plate press replaced by a handy squeegee costing only a few pence. I have allowed myself this historical digression believing not only that it is of interest, but being convinced that an understanding of past difficulties and errors is a great help to present success and ease of work.

For those working on an extensive scale or makin~ large prints developing tanks may be needed and a special ~ot water, supply ; but these cannot ~e regarded as a necessity for the smaller worker. Any ordmary tray or vessel, as the .domestic bath or basin and kettle will serve the P1:rpo~­ the squeegee and actinometer being the o~ly . pieces of apparatus ~bsolutely ess~ntial beyond the pnntmg frames and dishes m the possession of any photographer. '. . The insensitive tissue cut to pieces of the reqmred size, must be sensitized by immersion in a solution of bichron;ate -0f potash-allowed to dry in the .dark an~ ~xpos~d · tq light under a negative. As there is no vlSlble _imag~, an actinometer is used to gauge the exposure which will_ be approximately ! t~ ! of !hat need~d for a P. 0: P. prmt. The exposed tissue is then immersed m cold water (m ~corner ·o f a room removed from bright light) together with the transfer paper, opal or other base it is intende~ to be devefoped upon. In the cold water the tissue ~ill cu~l 1tself up more. or less according to the amount of moisture it already contams -just before it becomes flat or flaccid it is remo"."'e? from the water together with its support, placed on a ngid surface, and the squeegee passed lightly and evenly over the back of the tissue to expel superfluous water and secure contact between the two surfaces. The adherjng tissue and transfer .are next placed between blotting boards and allo~ed to remain about ten minutes, after which the operation of development may take place in full daylight; which is an .advantage in that it allows the picture t