Support for lithographic printing plate and presensitized plate

摘要

Disclosed is a presensitized plate, having intermediate and photosensitive layers sequentially provided on a support for a lithographic printing plate, which is provided by subjecting an aluminum plate to graining, alkali etching and anodizing treatments. The amount of alkali etching is set in a range of 0.5 to 4 g/m<2> for the alkali etching treatment, and an average thickness of thinnest 10% of the photosensitive layer on convex portions of a surface of the support is set in a range of 0.2 to 2 mu m. This presensitized plate has wide development latitude, makes it difficult for scratch-like non-image portions to be generated, and facilitates handling in usual operation.