B41M 5/366

Thermography ; {Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used } using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties {using materials comprising a polymeric matrix containing a polymeric particulate material, e.g. hydrophobic heat coalescing particles}