GB623872A - Improvements in multi-colour photography - Google Patents

Abstract

623,872. Colour photography. KODAK, Ltd. May 22, 1947, No. 13755. Convention date, June 28, 1946. [Class 98 (ii)] A multi-coloured photographic image is produced in a single silver halide emulsion layer by exposing the layer to a colour component image, developing in a colour forming developer adapted to form an image of silver and waterinsoluble dye, uniformly exposing the layer, developing all residual silver halide in a colour forming developer adapted to form an image of silver and water-soluble dye, washing the watersoluble dye out of the layer, rehalogenizing all developed silver to light-sensitive silver halide, exposing to a second colour component image, developing in a colour forming developer adapted to form an image of silver and a second water-insoluble dye, and removing all developed silver and silver salts from the layer. For a three-colour picture, the steps of uniformly exposing the layer, producing and removing a water-soluble image, and rehalogenizing, are repeated before removal of the silver, with production of a third insoluble dye image from a third colour component record. Cyan, magenta and yellow insoluble images may be produced in that order. The purpose of the formation of the soluble dye images, with their subsequent removal and rehalogenization of the silver, is to maintain uniformity of sensitivity characteristics throughout the layer. Any developing agents known in the colour development art may be used, preferably similar ones for each of the various developments. Colour couplers for forming the insoluble dye images may be such as described in Specifications 458,665, 493,952, 531,246, 531,312, 536,939, 538,914, 545,448, 553,507 and 558,855; and for forming the soluble dye images may be resorcinol, 1 : 3 - dihydroxy - 4 - chlorobenzene, 2: 4 - dihydroxy benzoic acid, phloroglucinol, salicylacetic acid, resacetophenone, o-phenolsulphonic acid, 1-naphthol-5-sulphonic acid, 2 - naphthol - 6 - sulphonic acid, 1 - amino - 8 - naphthol-4-sulphonic acid, 1-amino-8-naphthol- 3: 6-disulphonic acid, 1: 8-dihydroxy-naphthalene-3: 6-disulphonic acid, 2-amino-8-naphthol- 6 - sulphonic acid, 1 - phenol - 5 - pyrazolone - 3 - carboxylic acid, 1-p-sulphophenyl-3-methyl-5- pyrazolone, 1-p-sulphophenyl-5-pyrazolone-3- carboxylic acid, 3: 5 - diaminobenzoic acid, 1 : 3 : 5 - triaminobenzene, 2 : 4 : 6 - triamino - benzoic acid, 2:4: 6-triaminochlorobenzene, diethylmalonate or barbituric acid. In an example, resorcin is used as coupler for watersoluble images, and 2,4-dichloro-1-naphthol, 1-phenyl-3-methyl-5-pyrazolene and o-benzoyl acetanilide as couplers for the cyan, magenta and yellow insoluble images respectively, all procedures being of normal type.