| 摘要 |
PURPOSE:To enhance sensitivity and to elevate graininess remarkably without impairing sharpness by combining the first coupler with the second coupler different from each other in the dispersion process and reactivity at the early stage of development. CONSTITUTION:The first coupler dispersed in oil droplets has an oleophilic group and soluboe in a high-b.p. solvent. The second coupler dispersed into an aq. alkaline soln., preferably, has at least one acidic group, such as sulfonic or carboxylic group, and the coupler itself and a coloring dye are not diffused into a hydrophilic colloid. In an emulsion layer contg. both couplers the second coupler is soluble in alkali, and in a dispersed state, and since it is rapid in the early stage development reaction, graininess is remarkably enhanced. Not only graininess but also sharpness can be kept good by regulating the second coupler to <=50mol% or the total amt. |
