| 摘要 |
<p>Photographic material comprises a transparent support carrying (1) an Ag halide emulsion layer contg. photosensitive Ag halide crystals and Ag precipitating nuclei dispersed in a polymeric binder and (2) a non photosensitive layer next to layer (1) made up of Ag precipitating nuclei dispersed in a polymeric binder. The concentration of the Ag precipitating nuclei is such that by development in presence of an Ag halide solvent as a function of the exposure, an Ag image is obtained by development of the unexposed Ag halide crystals with a maximum density of at least 1.0 unit above the maximum density of the Ag image formed by development of the exposed Ag halide crystals. The process is used in additive colour photography for direct positive image formation by diffusion transfer. The nuclei consist of metallic sulphides or selenoids in colloidal noble metals at a concn. of 1-25 x 106 mole/sq. ft. The crystals are Ag iodobromide contg. 1-9% I2. The binder in (1) is gelative contg. 0.3-1.5 pts. dispersed silica and that in (2) deacylated chitin.</p> |
