The Role of Gelatin and So-Called Natural Impurities in the Ripening Processes in Photographic Emulsions

Paper presented at a symposium on “Photographic Gelatin” organized by the Science Committee of the Royal Photographic Society on 19–22 September 1967 in Cambridge.

Abstract

Certain hydrolysis products of gelatin, in contact with silver halide grains in a non-gelatin environment, induce an increase of sensitometric values (speed, gamma, fog) comparable with those values obtained by the normal ripening processes of emulsions. It is presumed that sensitization takes place as a result of the same reactions and by the same macromolecular components of gelatin as during chemical ripening. The so-called natural impurities in gelatin are not the specific sensitizers, but during chemical ripening they cause local reactions of hydrolysis of gelatin. In the case of hydrolysis of gelatin, performed by the other defined method, the above mentioned natural impurities are superfluous and even obstructive.

Notes

Paper presented at a symposium on “Photographic Gelatin” organized by the Science Committee of the Royal Photographic Society on 19–22 September 1967 in Cambridge.