To improve wash-off property in a washing process and to obtain excellent ink receptivity and water holding property by controlling the whole calcium ton content to a specified amt. or smaller in the all structural layers which constitute a lithographic printing plate.
This aluminum lithographic printing plate is produced by applying a physical developing nuclear layer on an aluminum base body which is preliminarily roughened and anodically oxidized, and then applying a silver hallde emulsion layer thereon. A gelatin is generally used as a protective colloid in the silver halide emulsion layer. Also a gelatin can be used for other structural layers. A gelatin subjected to desalting treatment is preferably used for the silver halide emulsion layer or other structural layers. Especially, a gelatin having <1000 ppm calcium ion content is used. Preferably, a gelatin with <500 ppm calcium ion content, and more preferably <300 ppm content is used.
NAKAGAWA KUNIHIRO
TANAKA ETSUJI
KONDO TOSHIRO
