PLATE PREPARATION METHOD OF LITHOGRAPHIC PRINTING PLATE

摘要

PROBLEM TO BE SOLVED: To provide a plate preparation method to stably improve the printing characteristics of a lithographic printing plate having an aluminum plate as a supporting body and using a silver complex salt diffusion transfer method. SOLUTION: In this plate preparation method, a material having physical development nuclei between an anodically oxidized aluminum supporting body and a silver halide emulsion layer is treated with a developer containing thiosulfate. The content of thiosulfate is >=0.04 mol per 1 L of the developer. The development is carried out in such a manner that the weight reduction of aluminum oxide of the supporting body after the plate preparation process is <=0.6 g per 1 m2.