| abstract |
A transfer printing medium comprising a substrate supporting a thermal transfer dye and a radiation absorber positioned to provide thermal energy to the transfer dye when subjected to radiation within a predetermined absorption waveband, has a radiation absorber which is an infra-red absorbing 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 or 16 positions (the "3,6-positions") of the phthalocyanine nucleus, as shown in Formula I, is linked by an atom from Group VB or Group VIB of the Periodic Table, other than oxygen, to a carbon atom of an organic radical. In preferred compounds each of the eight 3,6-positions is linked by an atom from Group VB or Group VIB, especially sulphur, selenium or nitrogen, to an organic radical. |