Planographic printing plate material and preparing process of planographic printing plate

摘要

A photosensitive composition containing: (A) a sensitizing dye; (B) a photopolymerization initiator; (c) a polymerizable compound having an ethylenically unsaturated bond; and (D) a polymer binder, wherein the photopolymerization initiator exhibits a reaction rate constant with a semiquinone radical anion in the range of 2.0x10² to 1.0x10⁸ (mol^-1.l.s^-1).