Traube / Diachromie

Subtractive 3 color: Mordant toning, still photography
“In the imbibition process, a dye image is transferred from a gelatin relief image to a receiving layer made either of paper or film. Charles Cros described this method of “hydrotypie” transfer printing in 1880 and suggested it ...

Toning / metallic toning (French: virage, German: Tonung)

Applied colors: Replacement of silver

In contrast to tinting, toning is not the simple immersion of a film into a dye bath but involves a chemical reaction converting the silver image. In this reaction the neutral silver image in the emulsion of the positive film is replaced by one consisting of colored metal compounds. These were usually iron ferrocyanide (Prussian Blue) for blue, copper ferrocyanide for red/brown, silver sulfide for sepia or rarely uranium ferrocyanide for reddish brown. Toning had been used in still photography before. But since film was projected on the screen it required translucent toning compounds.

1550 Images in 63 Galleries

Mordant toning / dye toning

Applied colors: Silver replacement by mordanting
Mordant toning or dye toning is a special case of toning whereby the silver image is replaced by colored compounds. Soluble dyes attach to a colorless (silver ferrocyanide) or nearly colorless (silver iodide) silver salt obtained by bleaching. Dye ...

171 Images in 7 Galleries

Curtis Neotone

Subtractive 3 color: dye mordanting process, still photography
“In 1939 Thomas S. Curtis of Huntington Park, California, introduced Curtis Neotone, a simple dye mordanting printing method for the production of color prints or transparencies from color separation negatives. With Curtis’s method, a ...