| 摘要 |
1,187,029. Photographic direct-positive process. GEVAERT-AGFA N.V. Oct.12, 1967 [Oct.24, 1966], No.47629/66. Addition to 1,151,363. Heading G2C. Direct positive images are produced by the process of Specification 1,151, 363 by imagewise exposing a silver halide emulsion which forms mainly internal latent image, and is in contact with at least one substance releasing I<SP>-</SP> in aq. medium, and surface developing while exposing to low intensity light, characterized in that the substance releasing I- is partly or wholly molecular I 2 and/or at least one of its addition products. The addition product may be the addition product of iodine with polyvinyl pyrrolidone, with a polyalkylene or with a quaternary ammonium compound. The said substance may be added as a soln. in H 2 O or a lower alcohol e.g. ethanol. The emulsion may also contain a H 2 O-soluble inorganic iodide e.g. KI and at least one compound setting free Br<SP>-</SP> in aq. medium e.g. KBr. The material, which may contain the developer, and the process details are otherwise as in Specification 1,151,363. The use of tetraethylammonium iodide-3-iodine as the substance releasing I<SP>-</SP> is disclaimed. |
