Compositions and methods for treating surface of lithographic printing plates

摘要

A liquid composition for treating surface of lithographic printing plates, especially etching liquid and dampening liquid which essentially consists of (a) phosphoric acids, (b) nitric acid or salts thereof and (c) nitrous acid or salts thereof and which has all characteristics required for treating liquids used for offset printing, has excellent ability of rendering the non-image areas oil-unreceptive and has rust resistance for all metals. This composition may additionally contain aminopolycarboxylates, polyol compounds and inorganic fine particles.