Support for lithographic printing plate and lithographic printing plate

Abstract

A lithographic printing plate support and a process for producing it are disclosed. The plate is produced by providing an aluminum alloy material which is comprised of 0.20 to 1.0% Fe, 0.005 to 0.1% of an element selected from the group consisting of Sn, In, Ga and Zn and the remainder being aluminum. The alloy may further contain 0.1 to 2% Cu. After providing the aluminum material either or both of its surfaces are subjected to a chemical etching treatment in order to provide a uniform and dense grain structure on the surface forming primary pits in the surface having a particularly defined average size. The surface is then subjected to electrochemical etching treatment in an acidic electrolytic solution in order to provide secondary pits on the surface also having a particularly defined average size. The support base may be further treated to provide in additional coating thereon or directly coated with a light-sensitive layer in order to provide a light-sensitive lithographic printing plate. By providing the particular alloy material and subjecting it to the disclosed treatment the light-sensitive layer has good adhesion with respect to the support.