The American Carbon Manual/Coloring Carbon Prints
COLORING CARBON PRINTS.
Carbon photographs, finished as described in the chapter on Mr. Swan's process, admit of coloring in oil, water or powder colors, with the greatest facility, and without risk of damage; the manipulation is easier than that upon albumenized silver prints.
Powder Colors adhere very readily to the surface of these prints. By breathing on the picture, a still more adherent surface is obtained. If greater depth of tint than can be secured in one application of the colors be required, a coating of a very thin varnish may be applied after the first tinting, and on a second application of the color, considerable depth and brilliancy will be obtained.
Water Colors.—If, after the final transfer of the print, the gelatine employed in the operation were not rendered insoluble by a solution of alum, or the chrome salt, the use of water colors on the print would be attended with danger, as the moisture would be absorbed by the gelatine used in transferring, and this film which forms the back of the picture would be apt to be disturbed by the abrasion of the pencil. When the print is properly finished, however, according to the instructions we have already given, there is no such danger. The water colors take kindly without any preparation, washing well, and permitting tint to be worked over tint without difficulty. The surface may be rendered still more pleasant for working on by the application of any good “sizing preparation.” Nothing can be better for water colors than the carbon print so treated. The plain carbon print so treated acquires an even, clear surface, losing all gloss without any loss of depth or transparency, which is very pleasing.
Oil Colors.—The best mode of preparing a carbon print for the reception of oil colors consists in sizing it with isinglass. A solution of about two per cent, of isinglass in equal parts of hot water and spirits of wine, carefully applied (not too hot) to the surface of the carbon print, with a flat camel's-hair brush, yields a surface upon which oil colors work admirably.
Retouching Carbon Prints.—In the ordinary process of retouching carbon prints, to remove small imperfections, it is only necessary to use the proper color in the usual way; but if a little gelatine, with a trace of a chromic salt, be employed with the color, or if any good "Sizing Preparation" be employed as the medium, instead of water, the color will, when dry, become insoluble, like the rest of the picture. If the retouching be effected with the same materials before transferring the print, it will, when the picture is finished, be under the image, and no inequality of surface, usually apparent after touching, will be seen. This method permits the character of a print to be considerably modified, without the manipulation being obtrusively apparent in the finished picture.