| 摘要 |
PURPOSE:To improve age stability by adding specific mercaptotriazoles to a silver halide emulsion after the end of physical maturation in producing a titled emulsion of high sensitivity by adding an electron acceptor, water soluble bromide, etc. to said emulsion. CONSTITUTION:After a fogging process of a silver halide emulsion for direct positive contg. >=50mol% silver chloride, an electron acceptor (e.g.; indole cyanine dye) or a halogen acceptor and the 1, 2, 4-triazoline-3-thion expressed by the formulaI(R1 is H, COR3, SO2R4; R2 is H, an aliphatic group, an aromatic group; R3, R4 are aliphatic groups, aromatic groups) or its deriv. are added thereto. Further, in order to increase sensitivity, required amts. of water soluble bromide and water soluble iodide are added, whereby a titled silver halide emulsion is obtained. The compound of the formulaIis embodied by compounds of the formulaI, formula III, etc. |
