| 摘要 |
<p>PURPOSE:To improve the graininess and sharpness by incorporating a nondiffusible coupler forming a dye which diffuses moderately during development by coupling with the oxidized product of a developing agent and a specified low mol.wt. coupler into silver halide emulsion layers. CONSTITUTION:A nondiffusible coupler (die diffusion type coupler) forming a dye which diffuses moderately by a coupling reaction with the oxidized product of a developing agent during development and a low mol.wt. coupler having 250-450mol.wt. are incorporated into separate silver halide emulsion layers. In case where the skeletons of the couplers do not contain a readily alkali- soluble group such as carboxyl of sulfo, both the low mol.wt. coupler and the dye formed by development are made nondiffusible. When the dye diffusion type coupler is incorporated into an emulsion layer, the graininess is improved by the moderate diffusibility of the resulting dye. Superior sharpness is provided especially by combining the dye diffusion type coupler with the low mol.wt. coupler. It is preferable that the dye diffusion type coupler and the low mol.wt. coupler are incorporated into adjacent silver halide emulsion layers.</p> |
