To obtain a colored heat-bleachable material with an anti-halation layer made of an antihalation compsn. which is rapidly bleached at a low temp. by incorporating a specified formazan dye, specified hexaarylbiimidazole and a specified film forming binder soluble in a polar org. solvent.

This material is a colored heat-bleachable material with an antihalation layer made of an antihalation compsn. contg. a formazan dye having absorption at 50-850nm, at least one kind of hexaarylbiimidazole as an oxidized arylimidazole dimer of a compd. represented by formula I or II and a film forming binder soluble in an org. polar solvent and having 45-150°C glass transition temp. In the formulae I, II, each of R, R', R1 and R2 is H, specified alkyl, etc., each of (m) and (n) is an integer of 0-5, each of X and X' is oxy or imino and Z is specified alkylene.