Method for making lithographic printing plate

Abstract

A method for preparing a lithographic printing plate which comprises imagewise exposing to light a presensitized plate useful for making a lithographic printing plate having an intermediate layer and a photosensitive layer on an aluminum substrate in this order and developing the imagewise exposed plate with a developer, wherein said intermediate layer comprises a polymer compound comprising at least a structure unit having an acid group and a structure unit having an onium group and said developer comprises an inorganic alkali salt and a nonionic surfactant having polyoxyalkylene ether group and pH of the developer ranges from 11.0 to 12.7. The method provides a lithographic printing plate, which shows good contrast between an image area and non-image area, no background contamination during printing, good stability with time and good printing durability.

Dependencies are inferred from the claim text.