Naturalistic Photography for Students of the Art.

by P. H. Emerson

Preamble.

“In giving a description of the various methods that are employed for reproducing photographs from nature for the copper-plate press, it is obvious that only those which are purely ‘automatic’ need be mentioned, as it is impossible to give a true rendering of those beautiful forms and delicate gradations of tone, which we see in nature, by any but automatic means. For so ever-varying and sudden are her changes, that it is by photography alone we are able to secure these effects, and having obtained them, we require a process which will give us our impressions, and one which will harmonize with printed matter when required for book illustration.

“This we have in the Intaglio plate, which gives the most perfect tonality, and possesses all the richness and quality of a mezzotint plate, with the same degree of permanency.

Grown and bitten plates.

“For convenience of description the different methods of producing Intaglio plates may be classed under two heads—‘Grown’ and ‘Bitten.’ I will first mention the ‘grown,’ and will endeavour to point out the characteristics of the different processes, so that a comparison may be made between them, with the object of determining the one best suited for the purpose. In all the growing methods the basis of the process consists in obtaining a gelatinous mould of the subject; the most usual and simple way being to develop a carbon print from a reversed negative on a polished copper-plate which has been previously silvered, to prevent the copper which is afterwards deposited upon it adhering; and to produce the grain which is necessary to hold the printing ink. The mould when wet is dusted over with powdered glass, sand, or the like, previously treated with wax or stearine, to assist its removal.

“When the mould is quite dry the gritty particles are removed by gentle rubbing, leaving the gelatine in a grained state. Plumbago is then rubbed well over the picture to render the mould conductive, and it is placed in the electrotyping battery and a stout cast taken. There is some little uncertainty attending the entire removal of the gritty particles, and great danger that in making the mould sufficiently conductive in the heavy portions, the fine work is destroyed by getting blocked with the plumbago. The former objection has been overcome by substituting powdered resins, which can be readily dissolved away without injury to the mould, and the latter by the introduction of a tissue containing granular plumbago, which while producing the necessary grain for holding ink, is one of the best conductors of electricity, so that no after-treatment is required.

“Similar to this is a process by which the grain is obtained by the action of light on a chemical substance, which crystallizes under the action of light, the crystals becoming larger the longer they are acted on by it. A deposit of copper is then made on the crystalline surface and a plate obtained.

“By these methods very satisfactory results may be obtained for certain classes of work where the range of tone is not great, they are more particularly suited for reproducing the works of early engravers, old cuts, etchings, pencil and crayon drawings, and similar work upon rough or grained surfaces. In fact, when printed upon old paper, as is sometimes done in particular cases, so closely do they resemble the originals, that the most expert judge would have great difficulty in detecting the reproduction from the original; but for reproducing nature work, where the scale ranges from the highest lights to the deepest shadows, these methods are not suitable without much hand-work, which is ruinous to the faithful rendering of the subject, and the introduction of the roulette which is used to give the necessary depth does not improve the appearance, as the depth obtained by it is heavy, and lacking that transparency which is so desirable in all classes of work from nature. The great drawback to these methods is that the grain produced is upon the surface of the plate, standing up in innumerable little prickles, and the only way of working up a plate is with the roulette and scraper (the nature of the grain being unsuited for re-biting). These, added to the soft nature of grown copper, as compared to rolled or hammered copper, which is used in the biting methods, necessitates the greatest care in printing, and usually require very strong and sometimes forcing inks to give the necessary strength, and although a plate be steel-faced it will not hold out for a large number of impressions.

“There are other ways of producing a grain upon a gelatinous mould by re-sensitizing and, when dry, dusting over the picture brocade powder, either coarse or fine, as the subject may require; the mould being previously treated with vaseline, or a similar substance, to allow of the powder adhering, and exposing to daylight for a short time. The powder is then removed, and it is ready for the battery, after being blackleaded. As all the growing methods resemble each other so closely, I will not mention any others, but will proceed with a short description of the biting processes.

Biting process.