Naturalistic Photography for Students of the Art.

by P. H. Emerson

“A polished copper-plate, preferably a hammered one, is thoroughly cleaned, to remove all traces of grease, and is dusted over with powdered asphalt or resin, and the plate heated until the powder becomes partially melted. A carbon print from a reversed transparency is next developed upon the grained plate and allowed to dry. The unprotected margin is then painted round with asphalt, or other resist-varnish, and a wall of bordering wax placed round the work. It is then ready for biting, which is done with perchloride of iron, the bare portions being first attacked; water is then added, and the biting proceeds to the next tone, and so on, adding water when required, until the solution has penetrated the thickest portions of the film. The greatest care must be exercised during this operation, and a careful watch kept lest the action remain too long on any part. The biting should proceed in a gradual manner, so that the values are not exaggerated. The plate is then rinsed in water, the bordering wax removed, and the pigment cleaned off with a little potash ley.

“The biting of a plate resembles very closely the development of a dry-plate positive, as the action may be seen throughout the operation as each successive tone is reached. There are many variations to the above method, and each worker has his particular way of producing the grain, making the mould, biting, &c., but they are all based on the one just described. As the introduction of the biting methods as commercially worked is of more recent date than the grown, less is known of it, and those who work it most successfully keep it secret, and were it known there is little likelihood of its being satisfactorily worked by any but those experienced in copper-plate work, as long and careful study is necessary to master those minute details which are so important to ensure good results. For so delicate are the operations, that the changes of weather, temperature, &c., play an important part, and must be attended to.

“One of the great advantages a bitten plate has over a grown is that the scale is greater than by any other method, and the nature of the grain admirably lends itself to re-biting should any parts require deepening. That is, re-entering the original work by covering the grained surface with a protective coating, which resists the action of the acid etching-fluid, and deepening those parts that may require it, stopping out with resist-varnish any portion where deepening is not wanted. This at once does away with the roulette, and the plate still maintains its original character. Re-biting is seldom required on a plate from nature, for with care a plate can be made which needs no after-work whatever, and when bevelled and steel-faced is ready for the press, notwithstanding the assertion that has been made to the contrary, which recognizes the process only as a basis for skilled after-work. It is needless to say that in all mechanical processes the very best negative is required to work from, for although a great deal may be done in the biting to counteract any defects in the negative, yet, if the negative is wanting in any particular, the after-result is sure to suffer. And here I wish to say that by the ‘very best negative’ I do not mean the ordinary photographer’s beau-ideal, but a negative which gives a true impression of the object photographed, and is full of the ‘quality’ and subtlety of nature.

“The grain obtained on a plate which is bitten, differs materially from one that is grown, inasmuch as in the former it is below the surface, and in the latter upon it, as previously described; consequently its wearing capabilities are far greater.

Another biting method.

“Another biting method which possesses the merit of ingenuity rather than utility, is of converting an ordinary bromide of silver positive into chloride of silver, by the action of perchloride of iron and chromic acid. The film when damp is brought into close contact with the face of a polished copper-plate. Chloride of silver now rests upon the copper-plate, more of it in the vigorous or dark portions, and less of it in the lighter, and by a galvano-chemical process the chloride of silver decomposes, forming metallic silver and soluble chloride of copper, and producing depths corresponding to the amount of chloride of silver present. The energy of the action may be increased by moistening the film with a weak solution of chloride of zinc, and a battery current seems necessary to produce good results. As can be seen, the process is a very delicate one, admitting of little if any latitude in working, and, unlike the first-mentioned biting process, will not permit of any work being put on the positive as is usually done in the first method for certain work where the darks are very hard and pronounced, and a great saving of after-labour avoided.

“It is advisable to say that the work done on the positive and plate to which I refer is done in connection with facsimile work, and not with ‘nature work,’ for in the reproduction of engravings the deep blacks of the engravings have to be reproduced, and since in nature there is no black of this kind we do not have to accentuate parts of the plates to produce it.”

CHAPTER XIII.
MOUNTING AND FRAMING.

Mounting and framing.

Having our print, the next question is how shall it be mounted and framed. There can, of course, be no laws for this, but we feel justified in making a few remarks on this head.