Acutance agents for use in thermally developable photosensitive compositions

Claim 1

A compound which has a maximum absorption of visible light between 440 and 460 nm and which provides a flare factor of less than 0.9 to photosensitive emulsion coatings said compound having the general formula: ##STR32## wherein: R 1 represents hydrogen, an alkyl group of 1 to 18 carbon atoms or an aryl group of 6 to 10 carbon atoms, the alkyl or aryl group optionally substituted by halogen, by an alkoxy group of 1 to 6 carbon atoms or by an aryl group of 6 to 10 carbon atoms; R 2 and R 3 independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or halogen; R 4 and R 6 independently represents hydrogen, nitro, cyano, a carbalkoxy group having 1 to 6 carbon atoms, or halogen, and at least one of R 4 and R 6 is a nitro, cyano, carbalkoxy group having 1 to 6 carbon atoms, or halogen; R 5 is hydrogen; or R 5 and R 6 together constitute a benzo group.