Photographic colour bleaching bath prodn. - by adding accelerator of 3-mercapto-s-triazole to conc soln., for silver halide gelatin emulsion

摘要

Prodn. comprises adding 3-mercapto-s-triazole bleaching accelerator of formula (I), and conventional additives, a bleaching accelerator conc. obtd. by condensn. of thiosemicarbazide and formamide and then water addn. with conventional additives to the soln.. Conc. pref. contains 18-30 wt.% of the cpd. of formula (I). The bleaching substance comprises the alkali- or ammonium-salts of iron (III) complexes of complex forming amino acids. Pref. the bleaching substance comprises a conc. of NH4-Fe(III)-ethylene- -diaminetetraacetic acid. USE/ADVANTAGE - Economic and environmentally friendly prodn. of a bleach bath for photographic colour materials of silver halide- gelatine emulsions.