Planographic printing plate material and preparing process of planographic printing plate

A planographic plate material comprising a support having thereon a photosensitive layer containing:

• (A) a photopolymerization initiator;
• (B) a polymer binder;
• (C) a polymerizable compound having an ethylenically unsaturated bond;
• and
• (D) an anionic dye,
• wherein the photopolymerization initiator is a an iron-arene complex, and the anionic dye has a solubility in methyl ethyl ketone of not less than 1 weight % based on the total weight of methyl ethyl ketone;
• and the anionic dye is represented by Formula (1):
• wherein R1 represents a substituted or unsubstituted alkyl group of 1 to 18 carbon atoms, or a substituted or unsubstituted aryl group;
• R2 to R11 each independently represents a hydrogen atom, F, Cl, I, Br, a substituted or unsubstituted alkyl group of 1 to 6 carbon atoms, a substituted or unsubstituted aryl group or -N(R12) (R13), provided that R12 and R13 each independently represents a substituted or unsubstituted alkyl group of 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group;
• and X+ represents a hydrogen cation, a monovalent alkali metal cation or an onium cation.