Abstract: A photosensitive lithographic printing plate comprising: a hydrophilic support; a photosensitive layer; and a protective layer, wherein the photosensitive layer contains a compound having an ethylenically unsaturated double bond, a high molecular binder having a crosslinking group and a hexaaryl biimidazole compound; and the protective layer has an oxygen permeability at 25° C. under one atmosphere of from 1.0 to 20 cc/m2·day.

Abstract: A photosensitive composition comprising: at least one photopolymerization initiator; an N-oxyamide compound represented by formula (1); and a compound of undergoing a reaction by an effect of at least one of a radical and an acid to irreversibly change in its physical or chemical property, wherein X, Y and Z each independently represents a monovalent substituent.

Abstract: A lithographic printing plate precursor comprising, in this order, a support, an undercoat layer and a photosensitive layer containing an infrared absorber, a polymerization initiator, a polymerizable compound and a binder polymer, wherein the undercoat layer contains a polymer compound having an acid group, and Ra, ?S and a45 of a surface of the support are satisfied with the following conditions (i) to (iii), respectively: (i) Ra: 0.2 to 0.40 ?m, (ii) AS: 35 to 85%, (iii) a45: 25 to 55%, in which Ra, ?S (%) and a45 are defined herein.