GB701054A - Photographic anti-fogging agents and emulsion stabilisers - Google Patents

Abstract

701,054. Photographic emulsions and developing solutions therefor. IMPERIAL CHEMICAL INDUSTRIES, Ltd. April 16, 1952 [April 26, 1951], No. 9745/51. Class 98(2) A photographic silver halide emulsion is treated, for stabilizing and antifogging purposes, at a stage not later than the development of a latent image therein, with a small quantity of a heterocyclic compound of the formula wherein X and Z represent the atoms necessary to complete a pyrazine, pyrazole, triazole, or thiazole ring, and R 1 is H, NH 2 , OH, SH, S-alkyl, or a hydrocarbon group. The compound (e.g. 2-amino- 4-hydroxypteridine, 5-amino-7-methyltriazolo pyrimidine, 2: 5-diamino-7-methylthiazolopyrimidine, 5: 7-diaminotriazolopyrimidine, 5-amino-7-hydroxytriazolopyrimidine, 2:4-diaminopteridine, or 5- amino-7-methylmercapto-isopurine) may be incorporated in the emulsion during manufacture (preferably after digestion), in a layer adjacent to the emulsion, or in the developer. The emulsion may be a blue-sensitive or coloursensitized emulsion containing a non-diffusible colour coupler. In example 1, a comparison is drawn between the fog and speed values for a silver iodobromide emulsion coated on glass plates, one of which is immediately exposed, developed, and fixed, and another is similarly treated after 8 days storage at 50‹C and 50 per cent relative humidity; another similar pair, containing 3 : 7-diaminotriazolopyrimidine, are similarly treated. In example 2, a similar comparison is drawn, using 2:4-diaminopteridine, with an emulsion containing 3 - (p-anisoylacetylamino) 4 - (N- methyl : N - octadecylamino) - benzoic acid. In examples 3 and 4, the procedure is similar, using 5-amino-7-methyltriazolopyrimidine, the emulsion in example 4 being a fast negative silver iodobromide emulsion: In example 5, a similar comparison is drawn, for fog values only, with a fast negative silver iodobromide emulsion containing the red-sensitizing dye Ma 1088 (B.I.O.S. Final Report No. 1355 page 82), and 2-(1-hydroxy-2- naphthoyl)-amino-1-N-methyl : N-octadecylaniline- 4-sulphonic acid, with or without 5-amino-7-methylmercapto-isopurine, the exposed material being colour developed with a developer containing 4-diethylaminoaniline. Specification 442,731 is referred to. According to the Provisional Specification, X and Z may represent the atoms necessary to complete a 5- or 6-membered heterocyclic ring containing 2 or 3 heteroatoms, other than an iminiazole ring and the compound may be incorporated in the support of the photographic material.