A PS plate comprises a surface-grained and anodized aluminum plate provided thereon with a light-sensitive layer of a composition comprising a light-sensitive substance and an alkali-soluble resin wherein the light-sensitive substance is a 1,2-naphthoquinonediazide-5- (or -4-) sulfonic acid ester of a polyhydroxy compound of formula (I): ##STR1## wherein substituents R.sub.1 to R.sub.4 may be same or different and each represents a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an alkoxy group or an alkenyl group; R.sub.5 and R.sub.6 each represents a hydrogen atom, an alkyl group or a group: ##STR2## a and c each represents 0-1 and b represents 0-4. The PS plate permits the complete removal of any pasting mark and has a high development latitude.