METHOD OF PREPARING SILVER HALIDE PHOTOGRAPHIC EMULSION FOR FLOODING Russian patent published in 1998 - IPC

FIELD: photographic emulsions. SUBSTANCE: invention relates to emulsions intended for use when manufacturing high-sensitivity infrachromatic photographic materials appropriate for measuring laser parameters, investigating plasma, taking photograph of heat relief, for defectoscopy, astrophysics, and art work restoration. Method consists in introducing, into molten silver halide photographic emulsion, spectral sensitization activator 2-heptyl-4-hydroxy-6 methyl-1,3,3a, 7-tetraazaindene, sensitization dye, supersensitizer, and flooding additives. Emulsion is divided into two equal parts. To each of them, before spectral sensitization activator - phenyl-di(p- anisyl)phosphine or 4,4'-bis(4,6-diphenyl-1,3,5-triazinyl-2- amino)stilbene-2,2'-disulfonic acid disodium salt is introduced, pyrocatechol is added and, as sensitization dye, compound with general formula where Z is benzothiazole, 5-methoxy-6- methylmercaptobenzothiazol, 6,7-benzobenzothiazole, 6- trifluoromethylmercapto-4-quino-, 6-perfluoropropyl-4-quino-, or 6- diethylsulfonamide-4-quino-; k = 0,1,2 or 3; l = 0 or 1; m = 1; A₂- A₅ is hydrogen, lower alkyl or alkoxyl; A₁ is H or A₁ and A₂, together, form 2-methyl-1,4-butylene or 2,2-dimethyl-1,4-butylene; A₁ = A₄ = H or, together, 2,2-dimethyl-1,4-butylene; 10^-6-10^-4, together, form pentamethylene; R lower alkyl; X is I, Cl, Br, methylbenzenesulfonate, or butanesulfonate. As supersensitizer, 2,5- di-tert-butylhydroquinone is used. Sensitization dye is advantageously added in quantity (0.6-28.0) x 0.000001 mol per 1 mol of AgHal, and supersensitizer in quantity (25-75) x 0.0004 mol/mol. EFFECT: essentially extended choice of high-sensitivity infrachromatic materials uniformly sensitized in 700-1150 nm spectrum region. 3 cl, 1 tbl