CYAN CHROMOGENIC LEUCO DYES FOR PHOTOTHERMOGRAPHIC MATERIALS

Phothermographic material capable of producing a high density cyan image upon image-wise exposure and thermal development at a relatively low temperature and for a short period of time. The photothermographic material of the invention comprise coated on a support base at least one light-sensitive emulsion layer containing: (a) a binder; (b) a silver source material; (c) a light sensitive silver halide in catalytic proximity to said silver source material, wherein said emulsion layer or an adjacent layer thereto comprises a chromogenic cyan leuco dye. The photothermographic material of the invention may be used to obtain good cyan image of suitable density in single colour or multicolour photothermographic articles. At the same time the chromogenic leuco dye is stable enough not to be oxidised by oxygen of the air or by simple heating and to limit the fog formation after development.