Method of preparing a lithographic printing plate

Abstract

A method of preparing a lithographic printing plate which involves providing a plate precursor comprising a grained and anodized aluminium substrate coated with a metallic silver layer, imagewise exposing the precursor by means of a high intensity laser beam, and treating the plate by chemical and mechanical means in order to remove stains on the plate surface. On exposure of the plate precursor, removal of the metallic silver layer occurs in the exposed areas. The method provides press ready plates free of background stain, which give a clean, even appearance in exposed areas and show high image resolution and excellent durability on press, while eliminating the requirement for the use of intermediate film and developer chemistry.

Dependencies are inferred from the claim text.