Patent GB-540368-A (GB)
Title: Improvements in and relating to colour couplers and to colour photographic materialscontaining them
IPC: G03C1/835
Filed: 1939-12-29
Abstract: 540,368. Colour photography. POTTS, H. E (Eastman Kodak Co.). Dec. 29, 1939, No. 33070. [Class 98 (ii)] A photographic light-sensitive emulsion of a silver salt, such as a silver halide, in a waterinsoluble water-permeable binder, such as cellulose nitrate, acetate, acetate-phthalate, acetatepropionate, acetate-butyrate, or ether, or collodion, or gum mastic, gum dammar, gum sandarach, or gum elemi, or polystyrene, polymethylmethacrylate, or polyvinyl acetate, or coumarone-indene resin, has dispersed therein fine discrete particles of a water-soluble colloid such as gelatine or agar-agar not containing lightsensitive silver salt, but containing a dye, a dye derivative, or a dye-forming substance. Hydrolyzed cellulose organic acid esters may be used for the binder. Multi-emulsion material including at least one emulsion of the above type may be (1) two layers, one of continuous type and one of two-grain type; (2) three layers, (a) each of continuous type, (b) two layers of continuous type and one of one-grain type in any order, or (c) two layers of one-grain type and one of continuous type in any order. Certain of the layers may be of the kind described and claimed in Specifications 524,154, 524,554, and 524,555. The colour processing baths may contain organic liquids or wetting agents to facilitate penetration. The porosity of the binder may be reduced or increased as described in Specification 540,366. Porosity may be decreased by hardening the binder with chromium salts. The emulsions may be treated before coating as described in Specification 540,367. Silver chloride or chlorobromide, if desired further sensitized to blue, may be used for the emulsion to record blue, and silver bromide for the emulsions to record green and red. Basic sensitizing dyes, such as pinacyanole or the neothiazolocarbocyanine from 2:4-dimethylthiazole, may be used for silver halide-cellulose ester emulsions, and acid dyes, such as erythrosin, may be employed with silver halide gelatine emulsions. Anti-halation or filter layers may be provided, and a sound track may be recorded in one or more of the picture emulsions or in a separate emulsion. Examples of colour couplers are 1:4-phenylenebis-3-(1-phenyl-5-pyrazolone) and cyanoacet- #-naphthalide. A transparent or opaque support, such as cellulose nitrate or acetate, or paper, may be employed. In an example, an alcoholic sodium hydroxide solution of 2- lauryl-4-chlorophenol is added to an alkaline gelatine solution and citric acid is added. The dispersion is added to an emulsion containing silver bromide, cellulose acetate propionate, ethylene chloride, and ethyl alcohol red-sensitized with 5-4-(3-ethyl-2-benzothiazolidine)-2-butenylidene-3-n-heptyl-1-phenyl-2-thio-hydantoin, additional ethylene chloride is added, and the emulsion is passed through a colloid mill or homogenizer and is coated on a support. In a second example a similar emulsion is green-sensitized with 5-(3-ethyl-2-benzoxazolylidene)-ethylidene- 3-n-heptyl-l-phenyl-2-thiohydantoin and the colour coupler employed is 2-cyanoacetyl-5-(p-secamylbenzoylamino)-ooumarone. In a third example the emulsion is not specially sensitized and the colour coupler employed is n-propyl-p-benzoylacetaminobenzene sulphonate. A two-layer material may have the red-sensitized emulsion described in the first example coated on a transparent support and the green-sensitive emulsion described in the second example as the upper layer. A three-layer material may have the emulsions described in the first, second and third examples coated as the bottom, middle, and top layers. The material may be processed by colour development of the latest images or after rehalogenation of the developed images or may be processed by reversal. P-phenylenediamine developing agents may be used. An energetic colour developer for emulsions with a cellulose acetate propionate binder has 2-amino-5- diethylamirotoluene hydrochloride as the developagent and also includes sodium hydroxide, sodium metaborate and 6-nitrobenzimidazole. The emulsions may be coated on opposite sides of the support. Specifications 408,273 [Group IV], 458,664, 458,665, 474,353, 475,784, 475,786, 478,933, 478,934, 478,942, 478,983, 478,984, 478,985, 478,986, 478,989, 478,990, 478,991, 493,952, 496,196, 496,245, 509,707, and 537,921 also are referred to.