METHOD FOR PREPARING OF BROMINE-IODINE-SILVER PHOTOGRAPHIC EMULSION Russian patent published in 1995 - IPC

FIELD: production of photographic emulsion. SUBSTANCE: method involves single-stream emulsification. The process is carried out by consequently adding solution 2 and solution 3 into solution 1 which contains gelatin, KBr, KJ, H(CF₂)₁₀CH₂OH and water. Said solution 2 and solution 3 contain AgNO₃ and water. Then separation of solid phase, washing, dispersing and chemical sensitizing take places. The latter process is carried out by using Na₂S₂O₃, KCNS, AuCNS and sodium benzenesulfonate. Then three spectral sensitizers are added to prepare for glazing. Ammonium salt of 3,3′-di-γ-sulfopropyl-9-aminothiacarbocyanine betaine is used as sensitizer I. (3, 3′-di-β-oxyethyl)-9-methyl thiacarbocyanine chloride is used as sensitizer III. Pyridine salt of 3, 3′-di-γ-sulfopropyl-5,5′-diphenyl-9-ethylthiacarbocyanine betaine is used as sensitizer III. Quantity of sensitizer I and sensitizer II are equal (1,5-2)·10^-4 M/M Ag Hal, quantity of sensitizer III is (0,9-1,2)·10^-4 M/M AgHal. Sequence of adding said sensitizers is as follows: I-II-III or II-I-III. The process is followed by adding stabilizer, wetting and tanning agents. Sodium salt of 2-mercaptobenzimidazole-5-sulfoacid is used as mentioned above stabilizer, its quantity being (3-9)·10^-5 M/M AgHal. Sodium salt of di-2-ethyl-hexyltetraethylene glycol ester of sulfosuccinic acid is used as wetting agent, chromic acetate of phloroglucinole being used as tanning agent. EFFECT: improves homogeneous distribution of sensibility in layers within 450-640 nm, increases photosensitivity. 1 dwg, 1 tbl