Patent GB-562854-A (GB)
Title: Improvements in photographic sensitive material and in colour correcting masks produced therefrom
IPC: G03C7/18
Filed: 1942-08-12
Abstract: 562,854. Photographic sensitive material. KODAK, Ltd. (Eastman Kodak Co., and Yule, J. A. C.). Aug. 12, .1942, No. 11264. [Class 98 (ii)] Light-sensitive photographic material consists of two silver salt emulsions containing colour couplers, one emulsion being effectively sensitive to green light but not to red light and the other emulsion being effectively sensitive to red light but not to green light, the couplers being adapted to produce with one and the same colour developer a yellow or green image in the green-sensitive emulsion and a magenta or blue image in the red-sensitive emulsion. The green-sensitive emulsion may contain couplers producing yellow and cyan images, and the red-sensitive emulsion couplers producing magenta and cyan images. Either or both of the emulsions may be divided into two parts, each part containing a different coupler. The emulsions and the parts thereof may be segregated as grains or coated as layers. The selective sensitizations may be obtained by the use of sensitizers in conjunction with filters. Green sensitizers specified are 2-diphenylamino-' 5 - (2 - ethyl - 1 - benzthiazylidene - ethylidene) - 4 - thiazolone, and 1 : 3<1>-diethyl-4 : 5-benzthia-2<1> cyanine iodide, and red sensitizers 3:3<1>:9- triethyl-5: 5<1>-dichlorothiacarbocyanine bromide and 3 : 3<1> : 9 - triethyl - 5 : : 5<1> - dichloroselenacarbocyanine bromide. The green- and redsensitive emulsions may be developable to equal equivalent gammas, or the cyan-coupler layer of the red-sensitive emulsion may give a slightly reduced gamma compared to the other layers. The material may be provided with an adhesive (e.g. a mixture of n-butyl methacrylate and chlorinated diphenyls or a soft gelatin) on one surface to permit attachment to a multi-colour record during exposure and processing of the former (to be used as a colour-correction mask) and during printing from the latter thus masked. Colour component negatives or a colour print may be made using white or coloured lights. The mask is of complementary light value to the multi-colour record. The original may be a subtractive positive or negative transparency on multilayer material, a real optical image projected from a lenticular film through appropriate filters, a multicolour screen image, a painting, or a still-life subject. A film may carry two layers, of which the lower is redsensitive, and contains a blue-coupler or a mixture of cyan- and magenta-couplers, and the upper is green-sensitive and contains couplers giving yellow or green dyes on development. A decolourisable magenta filter (e.g. the aluminium lake of aurine-tricarboxylic acid) may be interposed between the two layers, and a yellow filter (e.g. 2-hydroxy-5-phenylazobenzaldehyde) may be placed above the top layer. The film may be replaced by a thin support having an adhesive on the other side thereof. The red sensitive emulsion may comprise two layers containing cyan and magenta couplers respectively. The cyan coupler may be 5-(N- benzyl : N - naphthalene - # - sulphon) - amido - 1 - naphthol, the magenta coupler 2-cyanoacetylcoumarone - 5 - (N - y - phenyl - n - propyl) - p - tert.-amylsulphonamide, and the yellow coupler' #-(p-tert.-butylphenoxy)-ethyl p-(benzoylacetamino)-benzenesulphonate. The couplers may be dissolved in tri-o-cresyl phosphate or di-nbutyl phthalate and dispersed in the appropriate emulsions. Moderate speed fine-grain emulsions of gamma 0.36 to 0.7 may be used. After exposure by white light passed through a three-colour transparency (e.g. produced according to Specification 507,841), the material is developed in a developer comprising sodium sulphite, 2-amino-5-diethylaminotoluene hydrochloride, sodium metaborate and water, fixed in an acid hardening fixing bath, bleached in a bath comprising potassium ferricyanide, potassium bromide, benzyl alcohol, and water, rinsed, fixed in hypo, and washed. Specifications 450,958, 524,154, 524,554, 524,555, 531,246, 531, 312, 537,921, 541,589, 544,064, 553,196, 553,229 and 553,230 are also referred to.