PLATE MAKING METHOD FOR PLANOGRAPHIC PRINTING PLATE

摘要

PROBLEM TO BE SOLVED: To provide a plate making method for a planographic printing plate in which an IR absorbing dye such as a cyanine dye contained in an image forming layer is prevented from precipitating or depositing in washing and finishing sections in a plate making process and with which a high sharpness clear image can be obtained. SOLUTION: In the plate making method for a planographic printing plate in which an IR sensitive planographic printing plate having an image forming layer containing an IR absorbing dye is exposed to IR, developed and treated with a plate surface treating solution, the plate surface treating solution contains a compound having two or more phosphonic acid groups.