| 摘要 |
FIELD: light-sensitive materials. ^ SUBSTANCE: invention relates to silver iodobromide emulsions with nucleus/shell-type microcrystals 0.31-1.0 mcm in size intended for manufacture of high-sensitivity h-resolution photographic materials, Method of invention consists in preparing sees emulsion by performing controlled double-jet crystallization at constant pBr value (3.0-3.5) comprising simultaneously adding to gelatin- and water-containing solution 1: ammonia solution and silver nitrate and water-containing solution 2 and potassium iodide, potassium bromide, and water-containing solution 3 followed by crystallization of seed emulsion, precipitation of solid phase, dispersing and subsequent gelation of precipitate and allowing a shell to be grown on thus obtained silver iodobromide seeds by preliminarily preparing reaction volume containing solution 1, seed emulsion, and ammonia solution, creating pBr = 3.20.1 and performing double-jet crystallization by simultaneously introducing solution 2 and 3 into reaction volume, while, 3-5 min before termination of introduction of solutions, solution 3 is replaced by potassium bromide and water-containing solution. Further, solid phase is precipitated, precipitate is dispersed, pH and pBr values are adjusted to 6.50.5 and 3.00.2, respectively, and chemical ripening is performed. Photographic material is composed of substrate with, on one of its sides, in series disposed adhesive gelation substance layer, light-sensitive layer made from aforesaid silver iodobromide emulsion containing (i) spectral sensitizers selected from compounds covered by general formula ^ where R represents ethyl; R1=R2 sulfopropyl; Z beta-naphthol or 4,5-benzo-5'-methoxy; Z1 beta-naphthol, 4',5'-benzo-5"-methoxy, 4,5-benzo-5'-(dimethylthieno-2",3"), or benzothieno-3",2"; K+ represents 3,3'-diethylthiazolinonecarbocyanin betaine, 1,1'-diethylquino-2,2'-monomethinecyanine or dimethylamino, in amounts (0.5-3.0).104 mole/mole silver; (ii) stabilizers: tetraindolicyne derivatives; (iii) spectral sensitization activator selected from 3,3'-[1",2"-bis(ethoxy)ethyl]-bis[1-ethyl-2-methyl-5-chlorobenzimidazolium] ditosylate, 3,3'-[1",2"-bis(ethoxy)ethyl]-bis[1-ethylbenzimidazolium] diperchlorate, 3,3'-(tetramethylene)-bis(1-ethylbenzimidazolium] ditosylate, and 1,7-bis(N'-methylpyridinium-2'-bromide)-1,7-dithiaheptane, in amounts (0.5-3.0).104 mole/mole silver; and (iv) gelatin protective layer. The other side of substrate is coated by antihalation counterlayer. ^ EFFECT: essentially simplified emulsion preparation technology, extended assortment of photographic materials characterized by high sensitivity, resolution capacity, and low fogging. ^ 2 cl, 1 tbl, 17 ex |
