| 摘要 |
PURPOSE:To obtain a direct positive photographic sensitive material good in graininess by forming at least one emulsion layer composed of an internal latent image type core/shell type direct positive emulsion having an average grain diameter of <=0.25mum. CONSTITUTION:The direct positive emulsion giving effective results is composed of, preferably, monodispersed core/shell type silver halide grains having an average grain diameter of <=0.25mum, preferably, <=0.20mum. The grains may be used alone or in a mixture of some kinds so as to control the average grain diameter to <=0.25mum. The molar ratio of the silver halide grains in the core to those in the shell to be used is optional, but usually, a molar ratio of 1:2-10 is used. It is preferred for both grains to have the same composition, but their compositions may be different from each other. |
