Presensitized plate for use in making lithographic printing plate

摘要

A presensitized plate having: on an aluminum support, a thermosensitive layer containing a photothermal conversion agent which absorbs infrared rays and generates heat and a water-insoluble and alkali-soluble resin, of which solubility to an alkali aqueous solution increases by heating, wherein the aluminum support has a grained structure with large undulation and a grained structure with small undulation on a surface thereof. This presensitized plate is excellent in damage resistance and sensitivity, and after the plate is processed into a lithographic plate, it is also excellent in scum resistance and press life.