GB498869A - Process of colour photographic development - Google Patents

Abstract

498,869. Colour photography. KODAK, Ltd. May 10, 1937, No. 24629/38. Convention date, May 9, 1936. Divided out of 500,826. [Class 98 (ii)] In a process of three-colour photography in which three colour-record silver salt images on a single support are processed to different colours, one of the records is converted into a dye image by means of a developing solution containing alkali, little or no sulphite, and as developing agent a substituted hydroquinone of the benzene, naphthalene, or anthracene series giving rise to an insoluble quinone dye on development, the silver being subsequently removed without removing the dye. Two or more of the component images may be so treated. Suitable developing, agents are polyarylated hydroquinones, hydrogenated-1 : 4-anthraquinones, and #-naphthohydroquinones. In examples, 2: 5-diphenyl- 3 : 6-dibenzyl hydroquinone, 2: 5-dixylyl-hydroquinone, 2 : 5-di-p-tolyl-hydroquinone, 2 : 5- di-p-phenetyl-hydroquinone, octahydro-anthrahydroquinones, 2-phenyl-alpha-naphthol-hydroquinone, and diphenoxy-hydroquinone are specified. Amino derivatives which may be used are phenyl-diamino-hydroquinone, phenylmethyl-imidazol-#-naphtholquinone, 4-acetamino- 1 : 2-dihydroxynaphthalene, 2-acetamino-3- chlor-1 : 4-dihydroxynaphthalene, 2 : 8-diacetamino-1 : 4-dihydroxynaphthalene, and 2:5- diacetamino-hydroquinone. Other examples are the reduction products of alpha-naphthoquinone-diphenylmethane, of benzoquinonediphenylmethane and of the condensation product of alpha-naphthoquinone with Michler's hydrol, the arylazo derivatives or arylhydrazines of 1 : 2-dihydroxynaphthalene and the aryl hydrazo derivatives of alpha-naphthol. The Specification as open to inspection under Sect. 91 includes also the subjectmatter of Specification 500,826 as open to inspection under Sect. 91. This subject-matter does not appear in the Specification as accepted.