Photopolymerizable composition

A lithographic printing plate precursor comprising:

• a photopolymerizable composition, the composition including a binder, a polymerizable compound, a sensitizer, a photoinitiator, and a polythiol compound;
• wherein
• the composition includes, with respect to its total solid weight, at least about 0.01 wt. % of the polythiol compound and the polythiol compound is selected from one of the following formulae (I) or (II):
• wherein
• X1 means O, S, Se, or NR5;
• L1 means a linking group or a single bond;
• R1 to R5 mutually independent mean H, a non-metal atom substituent, or L1;
• m is an integer from 1 to 100;
• and
• for the case that m is 1, L1 includes at least one additional thiol group;
• wherein
• X2 represents O, S, Se, or NR6;
• Y1, Y2 mutually independent mean N or CR7;
• L2 means a linking group or a single bond;
• R6, R7 mutually independent mean H, a non-metal atom substituent, or L2;
• n is an integer from 2 to 100;
• the thiol groups of formulae (I) or (II) may also be present in their tautomeric thione form;
• and
• L1, L2 mutually independent mean alkylene, alkyleneoxy, alkylenethio, oxygen, sulfur, amino, alkylamino, amido, alkylamido, sulphonyl, acyloxy, or alkylsiloxane;
• or an alkylene chain containing acyloxy, ether, carbonate, thioether, hydroxy, phenyl, heterocylic, amino, thiol sulphonyl, amido, glycerol monoether, urethane, or urea functions.