| 摘要 |
1,164,494. Photographic silver halide lith materials. EASTMAN KODAK CO. Sept. 23, 1966 [Sept. 23, 1965], No. 42689/66. Heading G2C. Photographic light-sensitive silver halide materials in which the silver halide contains at least 50 mole per cent of chloride contain in the emulsion or an adjacent layer 0À01 to 3À0 grams of a water-soluble block copolymer of polyoxypropylene and polyoxyethylene per mole of silver and a 3-pyrazolidone silver halide developing agent. The block copolymer may contain up to 15% by weight of silicon. The emulsion binder may be replaced in part by an aqueous dispersion of a polymeric vinyl compound e. g. homopolymers and copolymers of unsaturated acids and esters such as acrylic acid and its esters. The emulsion may also contain onium salts such as omegahydroxydecyl-pyridinium perchlorate. Materials of the invention are compared with those in which the 3-pyrazolidone is replaced by other developing agents, e. g. -hydroquinone and metol. The materials are lith materials of improved emulsion speed and contrast. |
