Patent GB-524556-A (GB)
Title: Improvements in and relating to photographic materials and the processing thereof
IPC: G03C1/83
Filed: 1938-10-26
Abstract: 524,556. Colour photography; photographic toning processes. KODAK, Ltd. (Eastman Kodak Co.). Oct. 26, 1938, No. 10273/40. Divided out of 524,500. Drawings to Specification. [Class 98 (ii)] [Also in Group IV] Photographic material has at least one image containing a silver salt of a coloured heterocyclic compound containing a chromophoric group and being in the heterocyclic nucleus an imino group which is next to or next but one to a nitrogen atom in the nucleus having an unshared pair of electrons. Azo derivatives of the heterocyclic compounds are suitable. Parent heterocyclic compounds specified are 1:2:3-triazole, 1:2:4- triazole, indazole, 2-mercapto-5-aminothiobiazole, thiohydantoin, ethylenethiourea, mercaptobenzimidazole, thiourazole, dihydroquinazoline, perimidine, imidazole, tetrazole, tetrazolone, 1:2:3-triazolin, and pyrazoleanthrone. These compounds may have additional substituents or fused-on rings, which may contain chromophoric or auxochrome groups. Specific examples of suitable compounds are 1-(benztriazole-4<SP>1</SP>-azo)-2-hydroxy-3-naphthoic acid, 4-phenylazo-5-aminoindazole, 1-(p nitrophenyl) - 3-methyl - 4 - (benztriazole - 4<SP>1</SP> - azo) - 5 - pyrazolone, 4-(p-hydroxyphenylazo)-benztriazole, 4-amino-7-(o-carboxyphenylazo)-benztriazole, 1 - benztriazole-4<SP>1</SP>-azo)- #-naphthol, 4-amino-7- phenylazobenztriazole, 4-(benztriazole-4<SP>1</SP>-azo)- 5-aminoindazole, 4-amino-7-(benztriazole-41- azo)-benztriazole, 5-amino-4-(o-carboxyphenylazo)-indazole, 5-p-hydroxyphenylazo)-indazole, and 1-hydroxy-2-(5-benztriazole azo)-8- amino-3:6-naphthalene disodium disulphonate. Developed silver images may be bleached to a relatively insoluble silver salt such as silver ferricyanide, orthophosphate, arsenate, arsenite, chloride, bromide, oxalate, or cyanate, and then toned to a more insoluble coloured silver salt by treatment with a dilute alkaline, such as a sodium carbonate, or hydroxide, solution of the imino compound. Acid solutions may be used. In an example, a developed silver image is removed with an acidified potassium permanganate solution or a dichromate solution and the residual silver halide image is tone red to magenta by treatment in a sodium carbonate solution of 4-amino-7-(o-carboxyphenylazo)- benztriazole. In another example a developed and fixed silver-image is bleached in a solution containing potassium ferricyanide and potassium bromide or chloride, is washed, and is toned yellow with a sodium carbonate solution of 4-(o-carboxyphenylazo)-5-aminoindazole. In another example, a three-layer film, which may be hardened and provided with permeable intermediate layers, is exposed, and developed and the developed silver removed, and the residual silver salt image in the top layer toned yellow by treatment in a sodium carbonate solution of 1-(p-nitrophenyl)-3-methyl-4-(benztriazole-4<SP>1</SP>-azo)-5-pyrazolone containing a loading agent, such as those described in Specification 454,622. After washing the middle image is toned magenta with a weakly alkaline solution of 1-(benztriazole-4<SP>1</SP>-azo )-#-naphthol, the film is washed, and the bottom image toned blue-green with a sodium carbonate solution of 1-hydroxy- 2- (5 - benztriazole azo) - 7 - (p-nitrophenylazo) - 8 - amino - 3:6 - naphthalene disodium-disulphonate. The intensity of the final image may be reduced by treatment with an alkaline hypo or dilute ammonium hydroxide solution. Partial toning may be effected. The coloured silver salt may be converted into the salt of another metal, such as copper, tin, lead, gold, or mercury, by treatment with a salt of such metal in a solution containing ammonia, ethanolamine, or sodium thiosulphate. The reversed images may be developed and bleached to salts such as silver phosphate, ferricyanide, arsenate, or oxalate before toning. These salts may be used as the light-sensitive salts. Specifications 440,032 and 524,500, are referred to. 5-Aminoindazole is prepared by the reduction by hydrogenation of 5-nitroindezole in the presence of finely divided nickel. 4- and 5- Aminobenztriazole are prepared similarly. 4- and 5-Nitrobenztriazole are prepared by treating a cold suspension of 3- or 4-nitro-1:2- diaminobenzene in concentrated hydrochloric acid with sodium nitrite. 4 - Amino - 7 - (bentriazole - 7<SP>1</SP> - azo) - benztriazole is prepared by coupling diazotized 4-aminobenztriazole with 4-aminobenztriazole. 4-Phenylazo-5-aminoindazole is prepared by coupling diazotizedanilinewith5-aminoindazo'e. 4 - Amino - 7 - (o-carboxyphenylazo) - benztriazole, 4 - amino - 7 - phenylazobenztriazole, 4 - (benztriazole - 4<SP>1</SP> - azo) - 5 - aminoindazole, and 5 - amino - 4 - (o-carboxyphenylazo) - indazole are similarly prepared using the appropriate diazo compound with either 4- amino benztriazole or 5 aminoidazole. 1-(Benztriazole-4<SP>1</SP>-azo)-2-hydroxy-3-naphthoic acid is prepared by the reaction of diazotized 4-aminobenztriazole on 2-hydroxy-3-naphthoic acid. 1-(p-Nitrophenyl)-3-methyl-4-(benztriazole-4<SP>1</SP>-azo)-5-pyrazoline, 4-(p-hydroxyphenylazo) - benztriazole, 1 - (benztriazole - 7<SP>1</SP> - azo)-#-naphthol, 5-(p-hydroxy phenylazo)- indazole, and 1-hydroxy-2-(5<SP>1</SP>-benztriazylazo 7 - (p-nitrophenylazo) - 8 - amino - 3:6 - naphthalene disodium disulphonate are similarly prepared by the reaction of diazotized 4- aminobenztriazole, 5-aminobenztriazole, or 5- aminoindazole with the appropriate coupling component. The Provisional Specification refers also to metallic salts of organic compounds in general in which the metal has replaced the hydrogen atom of an -SH or =NH group, and gives the following additional examples of metallic saltforming compounds ; 3-amino-4-(o-carboxyphenylazo) - phenol; α-carboxyphenylazorhodanine; 3 - carboxy - 4 - hydroxyphenylazorhodanine; 1-thiocarbamido - 3 - methyl - 4 - (o-carboxyphenylazo) - 5 - pyrazolone ; 1 - allylthiocarbamido - 3 - methyl - 4 - (o-carboxyphenylazo) - 5 - pyrazolone ; 1:1 - (carbethoxy) (o-carboxyphenylazo) - acetonethiosemicarbazone; 1 - acetyl - 4 - phenylazothiohydantoin; 1 - (benztriazole - 41 - azo) - 2 - hydroxy - 3 - aminophenazine ; 1 - (o-carboxyphenylazo) - 2 - hydroxy - 3 - aminophenazine ; 4 - nitro - 2 - (benztriazole - 4<SP>1</SP> - azo) - phenol ; phenylazorhodanine; N-(thioacetyl)-2-hydroxy- 5-(o-carboxyphenylazo)-aniline ; and 5-(p-hydroxybenzylidene) - rhodanine. Specification 475,786 also is referred to.