Chromogenic print

[4] They are composed of three layers of gelatin, each containing an emulsion of silver halide, which is used as a light-sensitive material, and a different dye coupler of subtractive color which together, when developed, form a full-color image.

[7] The following year he filed a patent listing various color developers and dye couplers,[8] which have historically been used in Agfachrome and are still in use today in Fujichrome Velvia and Provia, and Ektachrome.

[9] In spite of this, Fischer never created a successful color print due to his inability to prevent the dye couplers from moving between the emulsion layers.

[10] This first solution to this problem was found by Agfa workers Gustav Wilmanns and Wilhelm Schneider, who created a print made of three layers of gelatin containing subtractive color dye couplers made of long hydrocarbon chains, and carboxylic or sulfonic acid.

They used ionic insoluble carbon chains which were shorter than Agfa's for their dye couplers, which were suspended within droplets of water in the gelatin layers of the print.

[3] Notwithstanding the success of chromogenic prints in the amateur and professional market, it wasn't considered a medium for fine-art photography up to the 1970s.

In its reaction to the print, the color developer is oxidized in the areas of exposed silver, and subsequently reacts with another chemical, the dye coupler, which is present throughout the emulsion.

As of 2017[update], the major lines of professional chromogenic print paper are Kodak Endura and Fujifilm Crystal Archive.

The LightJet and the Lambda both use RGB lasers to expose light-sensitive material to produce a latent image that is then developed using conventional silver-based photographic chemicals.

Figure from patent US2113329A , issued by Kodak, describing a photographic color process using color-coupling substances, such as the ones used in a chromogenic print.