A liquid radiation curable composition for inkjet printing comprising a photoinitiating system consisting of one or more photoinitiators selected from the group consisting of non-polymeric di- or multifunctional initiators, oligomeric or polymeric initiators and polymerizable initiators and one or more polymerizable co-initiators wherein at least one of said polymerizable co-initiators is a co-initiator according to Formula: wherein, R 1 and R 2 are independently selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkaryl group, an aryl group and a heteroaryl group; R 3 to R 6 are independently selected from the group consisting of hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an acyl group, a thioalkyl group, an alkoxy group, a halogen, an aralkyl group, an alkaryl group, an aryl group and a heteroaryl group; X is selected from the group consisting of O, S and NR 9; R 8 and R 9 are independently selected from the group consisting of hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkaryl group, an aryl group and a heteroaryl group; R 1 and R 2, R 1 and R 3, R 2 and R 5, R 3 and R 4, R 5 and R 6, R 4 and R 8, R 6 and R 8, and R 8 and R 9 may represent the necessary atoms to form a 5 to 8 membered ring; and at least one of R 1 to R 6 and R 8 comprises a polymerizable ethylenically unsatured functional group selected from the group consisting of acrylate, substituted acrylate, methacrylate, styrene, acrylamide, methacrylamide, allyl ester, allyl ether, vinyl ester, vinyl ether, fumarate, maleate, maleimide and vinyl nitrile, characterised in that the at least one of said polymerizable co-initiators corresponds to Formula: R 1 and R 2 are independently selected from the group consisting of methyl, ethyl, propyl and butyl; L represents a divalent linking group comprising at least one carbon atom; and R 10 represents hydrogen, methyl, ethyl, propyl or butyl; or that the at least one of said polymerizable co-initiators is selected from the group consisting of: and R 1 and R 2 are independently selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkaryl group, an aryl group and a heteroaryl group; R 3 to R 6 are independently selected from the group consisting of hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an acyl group, a thioalkyl group, an alkoxy group, a halogen, an aralkyl group, an alkaryl group, an aryl group and a heteroaryl group; X is selected from the group consisting of O, S and NR 9; R 8 and R 9 are independently selected from the group consisting of hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkaryl group, an aryl group and a heteroaryl group; R 1 and R 2, R 1 and R 3, R 2 and R 5, R 3 and R 4, R 5 and R 6, R 4 and R 8, R 6 and R 8, and R 8 and R 9 may represent the necessary atoms to form a 5 to 8 membered ring; and at least one of R 1 to R 6 and R 8 comprises a polymerizable ethylenically unsatured functional group selected from the group consisting of acrylate, substituted acrylate, methacrylate, styrene, acrylamide, methacrylamide, allyl ester, allyl ether, vinyl ester, vinyl ether, fumarate, maleate, maleimide and vinyl nitrile, characterised in that the at least one of said polymerizable co-initiators corresponds to Formula: R 1 and R 2 are independently selected from the group consisting of methyl, ethyl, propyl and butyl; L represents a divalent linking group comprising at least one carbon atom; and R 10 represents hydrogen, methyl, ethyl, propyl or butyl; or that the at least one of said polymerizable co-initiators is selected from the group consisting of: and