GB507009A - Improved photographic material for colour photography - Google Patents

Abstract

507,009. Colour photography. I. G. FARBENINDUSTRIE AKT.-GES. Dec. 7, 1937, No. 33866. Convention date, Dec. 9, 1936. [Class (ii)] Colour photographic material comprises a support carrying on one or both sides silver halide emulsions of different sensitivity and containing dyestuff formers, at least one of the emulsions being in the form of finely subdivided particles and at least one other being in the form of a continuous layer. Two or more differently sensitized emulsions may be distributed as small particles in a gelatine layer and one or more differently sensitized emulsions having different dyestuff formers may be arranged as continuous layers above this. The emulsion particles distributed in gelatine may comprise a green-sensitive hardened emulsion having a dyestuff former fast to diffusion and capable of conversion into a purple dyestuff and a red-sensitive hardened emulsion having a dyestuff emulsion fast to diffusion and capable of conversion into a blue-green dyestuff, and the continuous layers may comprise a yellow dyed layer and a blue-sensitive emulsion layer having a dyestuff former capable of conversion into a yellow dyestuff. A single yellowdyed emulsion may be used. The colour formers may be incorporated in the gelatine by the use of dispersing agents and may be made insoluble by the addition of precipitating agents. The three emulsions may contain dyestuff leuco-compounds fast to diffusion which develop silver halide, or may contain colour formers for colour development. Dyestuff formers may be used which lose their colourforming capacity at the places which contain silver, or the colour formers may be converted after normal development to dyestuffs and the silver dyestuff bleaching-out process employed. The emulsions may be developed to negatives by a normal developer and then developed to positives after re-exposure by colour development. Specifications 436,587, 455,556, 458,400, 465,823, 468,946, 479,838, 481,501, 483,000, 484,698, 488,048; 488,853, 489,093, 489,161, and 489,274 are referred to.