GB525874A - Improvements in and relating to colour forming developers and processes of colour development - Google Patents

Abstract

525,874. Photographic colour development. KODAK, Ltd. (Eastman Kodak Co.). Feb. 28, 1939, No. 3688/40. Divided out of 525,765. [Class 98 (ii)] A colour developer comprises an aromatic amino developing agent and a colour coup'er having the formula shown in Fig. 1, wherein C** represents a carbon atom in an aryl, aralkyl, or aryloyalkyl group, and C* represents a carbon atom in an alkyl group or in an aromatic nucleus. Examples of colour couplers are #- phenylacetylacetone, ethyl α-acetyl-γ-phenylacetoacetate, #-(phenacetyl)-acetophenone, 6- phenyl-n-hexanedione-2.4, 1:5-diphenyl-n-pentanedione-1:3, 1 - phenyl - 6 - methyl-n-heptanedione-3:5, and γ-phenoxybutyrylacetone. The reactive methylene group may have easily displaceable substituents such as halogen or carbalkoxy. The aromatic amino developing agents may be of the usual kind as specified in Specification 525,765. A suitable developing formula is given. The colour couplers may also be incorporated in the emulsion before or after exposure, and may be absorbed on the silver halide grains. The colour developer may be used in the formation of coloured images in plates, films, or papers having differently colour sensitized emulsions of the mixed-grain type or having differently colour sensitized emulsion layers superimposed on one or both sides of the support. Specifications 427,472, 427,516, 427,518, 427,520, 440,032, 440,089, and 447,092 also are referred to. The Provisional Specification describes also colour-couplers of the general formula in which Y may be aralkyl or alkoxy. An example given is 1-phenyl-4-ethoxy-n-butanedione 1:3. The colour coupler may also have the general formula where X is aryl substituted alkyl, aryl substituted alkyl or aryloxy substituted alkyl, and C+ is a carbon atom in an alkyl group or aromatic nucleus. X may be phenylmethyl, phenylethyl, phenoxymethyl, or phenoxypropyl. Additional examples given of colour couplers are 1-phenoxy-n-pentanedione-2:4, ethyl α-(phenoxyacetyl)-acetoacetate, 1-phenyln-hexene-1-dione-3:5, I-phenyl-n-hexanedione- 1:3, and 1-phenyl-n-pentanedione-2:4.