| 摘要 |
PROBLEM TO BE SOLVED: To provide an original plate for a planographic printing plate capable of improving residual color and residual film performances while retaining sensitivity, stain-proofing property and printing resistance. SOLUTION: The original plate has an image forming layer containing a photothermal converting agent on a metallic base subjected to electrolytic surface roughening treatment, anodic oxidation with an electric current having 1-30 A/dm2 average current density in an electrolytic solution having 300-500 g/l concentration of sulfuric acid and pore sealing treatment in this order. |
