Transfer printing medium with thermal transfer dye and infra-red radiation phthalocyanine absorber

A transfer printing medium comprising a substrate supporting a thermal transfer dye and a radiation absorber either intimately mixed in a common coating layer or arranged as separate layers on the same side of the substrate, thereby being positioned for the absorber to provide thermal energy to the transfer dye when subjected to radiation within the near infra-red region of the electromagneic spectrum, said radiation absorber being a poly(substituted)phthalocyanine compound in which each of at least five of the peripheral carbon atoms in the 1, 4, 5, 8, 9, 12, 13 and 16 positions of the phthalocyanine nucleus of Formula I ##STR3## is linked by an atom of nitrogen, sulfur, selenium or tellurium to a carbon atom of an organic radical, said organic radical being

• (i) an unsubstituted aliphatic radical,
• (ii) an unsubstituted cycloaliphatic radical,
• (iii) an unsubstituted aromatic radical,
• (iv) an aliphatic radical substituted by alkoxy, alkylthio, halo, cyano or aryl,
• (v) a cycloaliphatic radical substituted by alkoxy, alkylthio, halo, cyano or aryl, or
• (vi) an aromatic radical substituted by alkyl, alkenyl, alkoxy or alkylthio, or halo substituted derivatives thereof, aryl, arlythio, halogen, nitro, cyano, carboxyl, aralkyl, aryl-sulphonamido, alkyl-sulphonamido, aryl-sulphone, alkyl-sulphone, aryl-sulphoxide, alkyl-sulphoxide, hydroxy, primary amino, secondary amino or tertiary amino.