PURPOSE: To obtain a lithographic plate material superior in ink receptivity, printing resistance, etc., by forming an undercoat layer contg. a specified hardening agent on a support, a physical development nucleus layer, and then, a silver halide emulsion layer contg. a (thio)semicarbazide or its derivative, in succession.
CONSTITUTION: An undercoat layer 2 formed on a support of corona-discharge treated polyethylene coated paper or the like consists of a hydrophilic colloid, such as gelatin, contg. at least one hardener selected from a group (a) of precondensates of ethyleneurea and formaline, those of melamine and formalin, those of urea and formalin contg. uronic rings, and a group (b) of precondensates of ethyleneurea and melamine with formaline and those of urea and melamine with formalin. A physical development nucleus layer 3 is formed on the layer 2, and a photosensitive silver halide emulsion layer 4 contg. (semi)carbazide or a deriv. thereof is formed on the layer 3. When necessary, a protective layer 5 is formed on the layer 4 to obtain a lithographic plate material.
SAKAMOTO HIDEKAZU
ITOU NOBORU
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