| abstract |
Disclosed is a method for manufacturing a presensitized planographic printing plate comprising a support, and provided thereon, a light sensitive layer, the support having small pits with an average opening size of 0.2 to 0.8 mu m and a depth to size ratio of 0.2 or less, and large pits, the method comprising the steps of (a) chemically, mechanically or electrolytically graining the surface of an aluminum or its alloy, (b) electrolytically surface roughening the resulting aluminum or alloy in an acidic electrolyte solution, (c) chemically surface roughening the electrolytically surface roughened aluminum or alloy, (d) anodizing the chemically surface roughened aluminum or alloy, and (e) providing a light sensitive layer on the anodized aluminum or alloy. |