The present invention relates to IR-sensitive compositions containing an initator system comprising:
- (a) at least one compound capable of absorbing IR radiation selected from triarylamine dyes, thiazolium dyes, indolium dyes, oxazolium dyes, cyanine dyes, polyaniline dyes, polypyrrole dyes, polythiophene dyes and phthalocyanine pigments
- (b) at least one compound capable of producing radicals selected from polyhaloalkyl-substituted compounds
- (c) at least one polycarboxylic acid represented by the following formula I
wherein Y is selected from the group consisting of O, S and NR7, each of R4, R5 and R6 is independently selected from the group consisting of hydrogen, C1-C4 alkyl, aryl which is optionally substituted, —COOH and NR8CH2COOH, R7 is selected from the group consisting of hydrogen, C1-C6 alkyl, —CH2CH2OH, and C1-C5 alkyl substituted with -COOH, R8 is selected from the group consisting of —CH2COOH, —CH2OH and —(CH2)2N(CH2COOH)2 and r is 0, 1, 2 or 3 with the proviso that at least one of R4, R5, R6, R7 and R8 comprises a —COOH group or salts thereof, and
(d) at least one leuco dye, wherein the following inequation is met:oxa<redb+1.6eV
with oxa=oxidation potential of component (a) in eV redb=reduction potential of component (b) in eV
These compositions are inter alia extraordinarily suitable for the manufacture of printing plates.