Patent ID: 7467587

Claim:
A method for making a lithographic printing plate comprising the steps of (a) providing a heat-sensitive positive-working lithographic printing plate precursor which comprises a support and a coating thereon, wherein the coating comprises a novolac, a resole, or a polyvinylphenol; (b) exposing a halftone image comprising microdots having a size of 25 μm or less on the plate precursor by means of infrared light; and (c) processing the plate precursor in a developer, thereby removing non-image areas of the coating from the support; wherein the infrared light has an energy density in the range from CP to 1.5*CP, wherein CP is the clearing point which is defined as the minimum energy density that is required to obtain, after the processing step, an optical density of the coating at fully exposed areas equal to 0.05*D u , and wherein D u is the optical density of the coating in the unexposed state.