Printing plates

摘要

Aluminium or aluminium alloy is electrolytically grained using alternating current and an aqueous electrolyte comprising specified amounts of hydrochloric acid and a monocarboxylic acid containing from 1 to 4 carbon atoms, preferably acetic acid. The grained aluminium or alloy may be coated with a light sensitive layer to form a light sensitive plate for use in the production of lithographic printing plates by photomechanical techniques.