| 摘要 |
583,648. Photographic materials. KENDALL, J. D., and FRY, D. J. Nov. 13, 1944, No. 22332. [Class 98 (ii)] The quality of images developed in silver halide emulsions is improved by applying to the emulsions a heterocyclic compound of one of the formulµ where Y is O, S, or =NH. The compound may be included in the emulsion, in a water-permeable colloid layer coated adjacent thereto, or in a processing bath (e.g. a developing or fixing bath or a glazing solution). More than one such compound may be used, and the compound may be used both in a supercoat and in the developer or in both the developer and the fixing solution. The compound may be used in the form of an alkali metal or ammonium salt. Optimum quantities are specified. Compounds specified are 2 : 5 - dimercapto - 1 : 3 : 4-thiodiazole, 2-mercapto-5-amino-1 : 3 : 4- thiodiazole, 1-mercapto-4-hydroxyphthalazine, 1 : 4- dimercaptophthalazine and 2 : 4 - dimer - captoquinazoline. Examples are given of the addition of an ethyl alcohol solution of 2:4- dimercapto-1 : 3 : 4-thiodiazole to a silver chloride emulsion, to a silver bromide emulsion, and to a gelatin supercoat solution of ethyl alcohol solutions of 1-mercapto-4-hydroxyphthalazine, 1:4- dimercaptophthalazine, and 2 : 4 - dimer - captoquinazoline to a gelatin supercoat solution and of an aqueous sodium carbonate solution of 2 : 5-dimercapto-1 : 3 : 4-thiodiazole to an acid hypo fixing bath. Bronzing after hot glazing is reduced. The compounds may be applied to already dried prints to be hotglazed. Specification 573,745 is referred to.
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