Desensitizing gum lithographic plate finisher.

摘要

A desensitizing gum lithographic plate finisher comprises water-soluble starch modified with urea-phosphoric acid containing 0.01 to 3% by weight of bound phosphorus and having a viscosity determined on 20% by weight aqueous solution at 30 DEG C ranging from 15 to 300 cps. The plate finisher can also be used as an aqueous phase of an emulsion type plate finisher. The finisher has high desensitizing ability and excellent low temperature storability and does not cause any reduction in the ink receptivity of image areas of lithographic printing plates.