Patent ID: 7655382

Claim:
A method of processing a lithographic printing plate comprising in order: (a) providing a lithographic printing plate comprising on an aluminum substrate a photosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to a laser having a wavelength selected from 200 to 1200 nm; wherein said aluminum substrate is electrochemically gained, anodized, and further treated with a phosphate fluoride aqueous solution, and has a reflection optical density of at least 0.30; (b) imagewise exposing said plate with said laser to cause hardening of the photosensitive layer in the exposed areas; (c) heating said exposed plate to 50 to 200° C. for 1 to 300 seconds; and (d) developing said heated plate with ink and/or fountain solution on a lithographic press to remove the non-hardened areas of the photosensitive layer.