A printing system is disclosed for thermal transfer printing onto a surface of a substrate. The system comprises a transfer member having opposite front and rear sides with an imaging surface on the front side, a coating station at which a monolayer of particles made of, or coated with, a thermoplastic polymer is applied to the imaging surface, an imaging station at which energy is applied by a thermal print head via the rear side of the transfer member to selected regions of the imaging surface to render particles coating the selected regions tacky, and a transfer station at which the imaging surface of the transfer member and the substrate surface are pressed against each other to cause transfer to the surface of the substrate of the particles that have been rendered tacky.