Patent GB-503823-A (GB)
Title: Improvements in materials for colour photography
IPC: G03C7/327
Filed: 1937-07-07
Abstract: 503,823. Colour photography. KODAK, Ltd. July 7, 1937, No. 7951/39. Convention date, July 7, 1936. Divided out of 503,752. [Class 98 (ii)] A three-colour photographic element of the kind having three differentially colour sensitized silver halide emulsions inseparably coated on a single support has in one or more of the emulsions a coupling component in which a coupling function is repeated more than twice in the same molecule and which is not more soluble in water or in a solution of sodium carbonate in water than the most soluble of tri-alpha-naphthol triazine, alpha-naphthol-2-carboxylic acid-alpha (or -#)-nažhthylamide, alpha-naphthol-4- benzoyl ketone and the nydrazone of the latter. The coupling function is : (1) An -OH group in an aromatic nucleus with either the ortho or para position free or occupied by radicals which split off during coupling, or (2) an -NH2 group in an aromatic nucleus as in (1), or (3) a reactive methylene group in an open chain, or.(4) a reactive methylene group in a heterocyclic nucleus, or (5) An -NH-SO2-R group in a compound of the general formula X-NH-SO2-R, where R is alkyl or aryl and X is an aromatic nucleus with the ortho or para position free or occupied by radicals which split off during coupling, as described in Specification 503,827. Different coupling functions may be provided in the same molecule. The emulsions may all be coated in superimposed layers on a single support and each of the emulsions may contain a coupling component in which the coupling function is repeated more than twice in the same molecule. Coupling components in which the coupling function is repeated more than twice in the same molecule may be obtained by combining more than two molecules of a compound containing a coupling function with an aliphatic colloidal polyhydroxy compound such as a carbohydrate, for example a polyamylose. The polyhydroxy compound may be cellulose or a partially alkylated cellulose or polyvinyl alcohol or partially alkylated polyvinyl alcohol or partially acylated polyvinyl alcohol. The coupling component may also be obtained by combining more than two molecules of a compound containing a coupling function and a polymerized compound, such as one produced by polymerizing a phenol having an unsaturated side chain or such as urushiol or Japan lacquer. The coupling component may also be obtained by combining more than two molecules of a compound containing a coupling function with a polyamino compound or by combining a compound containing a coupling function with a polymerizable hydroxy compound and then bringing about polymerization. Reference is made to the tables of compounds in Specification 503,752 for examples of suitable coupling components. The processing of the photographic elements can be carried out as described in Specification 503,752 or 503,824. The photographic element may have a layer of colloidal silver in any emulsifying medium permeable to water on either side of the support to serve as anti-halation protection and may carry a sound track which can be in an almost grainless silver halide emulsion layer separate from those receiving the colour component images and sensitized to infra-red. Specifications 376,746, 376,794, 376,795, 440,032, 440,089, 447,092, 458,664, 475,784, 475,786, 479,838, 498,869, 498,870, 498,871, 498,875, 499,185, 503,752, 503,816, 503,817, 503,818, 503,819, 503,820, 503,821, 503,824, 503,825, 503,826, 503,827, 603,940, and 503,941 also are referred to.