Method for preparing lithographic printing plate

摘要

A method for preparing a lithographic printing plate includes: exposing a lithographic printing plate precursor including a hydrophilic support, a photosensitive layer containing (A) a sensitizing dye having an absorption maximum in a wavelength range of from 350 to 450 nm represented by the formula (I) or (II) as defined herein, (B) a polymerization initiator, (C) a polymerizable compound and (D) a binder polymer and a protective layer in this order with laser of from 350 to 450 nm; and removing the protective layer and an unexposed area of the photosensitive layer in the presence of a developer having pH of from 9 to 11 and containing an alkali agent, a surfactant and a water-soluble polymer compound by an automatic processor.