Patent GB-533568-A (GB)
Title: Improvements in and relating to colour photography
IPC: G03C7/30
Filed: 1939-06-16
Abstract: 533,568. Colour photography. SCHINZEL, K., and KODAK, Ltd. June 16, 1939, No. 17622. [Class 98 (ii)] A coloured image is produced in a photographic emulsion by treating an image containing an organic compound having a reactive carbonyl group, such as a quinone, an α:#- diketone, or a sulphonyliminoquinone, with an arylhydrazine or an arylhydrazide. The image may be obtained by developing a silver salt image with a coupling developer, which may contain an aromatic amino group as the developing agent, in the presence of a coupling component consisting of an aromatic compound having a hydroxyl group on the nucleus and a carbonyl group attached to the nucleus and treating the resulting coupled product with acid to split it. The acid splitting may be effected at the same time as the treatment with an arylhydrazine or arylhydrazide. The organic compound is preferably a quinone dye or other quinonoid or lignoid or semi-lignoid compound. The organic compound may already contain a carbonyl group more reactive than that produced on splitting, such as an aldehyde or ketone group. Filter dyes which themselves or whose decomposition products react with the arylhydrazine are removed before the treatment with the arylhydrazine. Carbonyl compounds specified are benzoquinone, 1:2 or 1:4- naphthoquinone or 1:2- or 1:4-anthraquinone or 2 - tetramethyldiaminodiphenylmethyl - 1 : 4 - naphthoquinone. Quinones formed from coupling components with high-molecular or highly polymeric residues or containing one or more substituents such as alkyl, acyl, aryl, arylamino, or acylamino groups may be used. If the coupling components containing basic substituents such as amino or quaternary ammonium groups, the acid-splitting and combination with the arylhydrazine is effected in the presence of phosphotungstic acid or its salts or a similar acid or its salts. A three-layer material contains α-naphthol-2-carboxylic acid naphthalide or a lauryl derivative in the red-sensitive emulsion, #-naphthol-3-carboxylic acid cerylamide in the green-sensitive emulsion, and the condensation product of salicylic acid chloride with cholestylamine, other high-molecular amine, benzidine, or dianisidine or a phenol or aminophenol substituted by a ceryl group in the bluesensitive emulsion. After development of the latent images with a non-coupling developer, the residual silver halide is developed with a coupling developer containing, for example, p-aminodimethylaniline as the developing agent. The colours produced are incorrect, but by treatment with a solution of a salt of o- or p-nitrophenylhydrazine in 2 per cent. aqueous hydrochloric acid, nearly correct azo dye images are produced. In another example, the redsensitive emulsion contains #-stearylamino-α- naphthol or its 3- or 6-sulphonic acid, the green-sensitive emulsion the stearoylamide of #-naphthol-3-carboxylic acid or 4-stearoylamino-α-naphthol or 4-stearoylamino-,8-naphthol or the 1-sulphonic acid of the latter, and the not specially colour sensitized emulsion 1-phenyl-3-stearyl-5-pyrazolone. After coupling development and acid-splitting, the resulting quinones are reacted with the dihydrazine of benzidine or of a nitrobenzidine. With paper supports, the quantity of components may be reduced to half or less. Coupling components are preferably used in non-diffusing form. Insoluble phenols, or naphthols, in soluble salts of phenols or naphthols, insoluble sulphonic acids, carboxylic acids, or sulphonamides of coupling components, pseudo soluble salts of these acids with bases such as caustic alkalis, ammonia, mono-, di-, or tri-ethanolamine, ethylenediamine, or piperidine, or insoluble salts of these acids with high-molecular bases such as diphenylguanidine or quaternary heterocyclic bases may be used. The coupling component may also be in the developer. Developers directly yielding quinones, such as those described in Specification 498,869, may be used. Coupling components referred to are nitrobenzyl cyanide ; dinitrophenylacetanilide ; or the dianilides or anilidoesters of malonic acid and similar compounds as described in Specification 489,164, of sulphoacetic acid or of methionic acid ; acetylacetone, acetoacetanilide; phenylmethylpyrazolones and the di- and triarylalkylpyrazolones referred to in Specification 503,941 ; the coupling components referred to in Specifications 503,318 and 504,376 ; and dinitrotoluene. Hydrazines specified are phenylhydrazine ; arylhydrazines substituted in o- or p-position by a nitro, sulphonic acid, sulphamide, or carboxylic acid group or by a halogen atom, for example 2- or 3-hydrazinobenzoic acid and hydrazines having in one or more other positions in the molecule substituents such as a halogen-atom or a sulphonic acid group, such as p-phenyl-diphenyl hydrazine containing a hydroxyl or amino group in the nucleus not attached to nitrogen, for example N-#-hydroxyethylamino-diphenyl-p<SP>1</SP>-hydrazine, and similar derivatives of naphthylhydrazine ; salts of o- and p-nitrophenylhydrazines and of nitrated higher homologues and derivatives such as phenylenedihydrazines, diphenylenedihydrazines, diphenylmethanedihydrazines,3:5- bis-phenylhydrazinophenol, fuchsinetrihydrazine, and other hydrazines referred to in Specification 503,941 ; N:N-diphenylhydrazine, the hydrazines and dihydrazines of anthraquinones and their leuco derivatives, hydrazines derived from fluorene, dehydrothiotoluidine, or primuline base, other aromatic or heterocyclic hydrazines, aliphatic hydrazines, or the asymmetrical acyl, aryl- or alkyl-derivatives of these, and derivatives of any of these hydrazines containing substituents such as nitro, sulphonic acid, or sulphamide groups, or halogen atoms ; aliphatic, aromatic, and heterocyclic hydrazides, such as benzoyl hydrazide, benzoylphenylhydrazide, hippurylhydrazide, phenylcarbamic acid hydrazide, cyanuric trihydrazide, and benzenesulphonhydrazide ; the hydrazines of leuco dyes such as the hydrazine from m-amino Malachite Green and the hydrazines prepared from the leuco sulphuric esters of 5- or 6-aminothioindigo or 2-aminoarthraquinone. The developing agents specified are p-aminodimethylaniline ; the aryl- or alkyl-sulphonyl derivatives of p-arylenediamines; N:N<SP>1</SP>-disulphonyl derivatives of 1:2-naphthalenediaamine ; the N-sulphonyl derivatives of the 4-sulphonic and 4-carboxylic acids of 2-amino- α-naphthol and 1-amino-#-naphthol; and 1:5- dichlor-2:6-dihydroxynaphthalene. Development may be effected with 1:2-dihydroxynaphthalene-4-sulphonic or -carbonic acid in neutral or weak alkaline solution in the presence of aromatic amines, and the resulting compounds heated with acids to hydrolyse them to quinones which are condensed with phenylhydrazine or its nitro derivatives. If the resulting azo dyes or the hydrazones or the original coupling components contain complex forming groups such as the biguanido, o-hydroxy, mercapto, o-hydroxyquinoline, or salicylic acid group, or an azole or imidazole ring, they can be converted into complex salts by treatment with metal salt solutions. If the final dye contains basic groups such as dimethylamino, methylamino, or amino groups, fastness to light may be obtained by treatment with phosphotungstates or similar complex compounds either under neutral or acid conditions. An indophenol image in one emulsion may be split by acid of low concentration without affecting an azonethine dye image in another emulsion on the same support. The indophenols obtained from #-naphthol are less resistant to acids than those obtained from α-naphthol or halogenated α-naphthol or halogenated phenols, or the azomethines. A three-layer element is described having in the bottom layer an α-naphthol, the middle layer a #-naphthol, and the top layer an acetoacetic ester or a halogenated phenol. Dilute or weak acids split the coupled product in the middle layer and a magenta image is formed by the action of phenylhydrazine. Stronger or more concentrated acid splits the blue α-indonaphthol in the bottom layer and a blue-green azo dye image is obtained by the action of o- or p-nitrophenylhydrazine. The coupled product in the top layer is split by still stronger or more concentrated acid and a yellow image is obtained by the action of nitrophenylhydrazine. Only one or two images may be converted into azo dye images. Different hydrazines or hydrazides may be used for each image. Quinones simultaneously obtained by acidsplitting may be reacted with different arylhydrazines or hydrazides having different reaction speeds with the quinones. A red image is obtained by the action of phenylhydrazine on α- or #-naphthoquinone. Another high-molecular benzoquinone image would be simultaneously reduced, and may be reoxidized and converted to a yellow image by the action of m-nitrophenylhydrazine. Reoxidation by acidified potassium dichromate is necessary where a hydroquinone is obtained by acid splitting. Colloids other than gelatine, for example polyvinyl esters or hydrolysed cellulose esters, may be used as the emulsion binder. Specifications 440,032, 465,823, 500,717, 500,753, 500,826, 501,000, 501,001, 501,002, 503,752, and 507,841 also are referred to.