METHOD OF PRODUCING BROMINE-IODINE-SILVER EMULSIONS Russian patent published in 1995 - IPC

FIELD: photographic chemistry. SUBSTANCE: controlled double-jet emulsification is carried out at values of pBr=2.9-3.2 and pH=8.0-11.5. Spectral sensitizer is introduced into the emulsion during the second half process of emulsification, i.e.3-50% time before finishing emulsification. Limit of sensitization of the sensitizer is in 520-530 nm. The sensitizer is chosen from 3,3'-diethylthiazolocarbocianinetolusulphonates or triethylammonium salt of 3,3'-di-γ-sulphopropylthiazolino carbocianine in amount of 8.8x108,8·10^-4-2.64x1010^-3 Mole/mole AgHal or 3-ethyl-5(1'-methylen-di-hydro(1',2') pyrydilyden-2'-thyazolydinthion(2)on(4) in amount of 2.0x1010^-4-3.3x1010^-4 mole/mole AgHal. The solid phase is separated. Residual received is twice dispersed in aqueous-gelatine solution of chemical sensitization under presence of thisulfate sodium, benzenesulphinoacid sodium and aurumchlochloronitric acid and spectral sensitization. Short-wave sensitizers are introduced into the emulsion, as a result, general light sensitivity of materials produced with application of emulsions mentioned above, increases by 20-60% in comparison with prototype and general photographic characteristics are preserved. EFFECT: efficiency. 1 tbl