| 摘要 |
PURPOSE:To obtain an image high in density, low in fog, and small in stains by heating a photosensitive element containing at least photosoensitive silver halide and a reducing substance on a support in the presence of a complex of polyhydroxy compound with alkali metal borate. CONSTITUTION:The photosensitive element is heated in the presence of the complex of the polyhydroxy compound with the alkali metal borate. The reaction proceeds revesibly, for example, as shown in chemical equation I, where as the polyhydroxy compound, 2,4-amylene glycol is used and as the alkali metal borate, NaB(OH)4 is used. The equilibrium of the reaction tends toward the left at room temperature, and toward the right at high temperature, and pH is controlled by this reaction. It is preferred to use as the polyhydroxy compound, a synthetic polymer composed of structural units derived from the monomers among which at least one monomer contains an OH group. |
