| 摘要 |
PURPOSE:To prevent halftone images from being generated due to halation, by a method wherein a surface of an aluminum plate is roughened, is etched, and then an anodic oxide film treated to be colored is provided. CONSTITUTION:After subjecting the surface of the aluminum plate to a degreasing treatment to remove a rolling oil or the like therefrom, the surface is roughened by a mechanical roughening method, a chemical roughening method or an electrochemical roughening method to enhance the water-retaining property and adhesive property of the surface for a photosensitive material layer coated thereon. The surface thus roughened is subjected to an alkali etching with an etching amount of about 5g/m<2> to enable a coloring treatment to be performed uniformly. The surface thus etched is neutralized by washing with an acidic solution, and is colored by an anodic oxidizing treatment method or the like. The coloring is preferably such as to attain an absorptivity of not less than 0.4 for wave lengths of 340-500nm. |
