Photographic polymeric film supports containing photobleachable o-nitroarylidene dyes

An otherwise transparent polymeric photographic film support having incorporated therein a photobleachable dye having the following formula:

• ##STR12## wherein:
• a. k represents 0 or 1;
• b. m represents 0 or 1;
• c. each L represents a methine group;
• d. A represents oxygen, sulfur or N--R.sub.1 ;
• e. Z.sub.1 represents the nonmetallic atoms completing a 5- or 6-membered heterocyclic ring selected from the group consisting of an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, a 3,3-dialkylindolenine nucleus, an imidazo[4,5-b]quinoxaline nucleus, a thiazoline nucleus, a pyridine nucleus, an imidazole nucleus, a quinoline nucleus, a 3H-pyrrolo[2,3-b]pyridine nucleus and a thizolo[4,5-b]quinoline nucleus, a 2H-pyran nucleus, a 4H-pyran nucleus and a dithiolane nucleus;
• and
• f. Y represents the atoms necessary to complete a nitro-substituted phenyl or 1-naphthyl group having a 4-ring position electron-withdrawing group, a nitro-substituted phenyl group having a 6-position electron-withdrawing group or a nitro-substituted phenyl group having 4- and 6-ring position electron-withdrawing groups.

An otherwise transparent polymeric photographic film support consisting essentially of polyethylene or poly(ethylene terephthalate) having incorporated therein a photobleachable dye, wherein said dye is selected from:

• a. 2(2,4-dinitrobenzylidene)-1,3-diethyl-2,3-dihydro-1H-imidazo[4,5-b]quinoxa line;
• b. 2-(2,4-dinitrobenzylidene)-3-ethyl-2,3-dihydrothiazolo[4,5-b]quinoline;
• c. 2-(2,4-dinitrobenzylidene)-3-ethyl-6-nitrobenzothiazoline;
• d. 2-(2,4-dinitrobenzylidene)-1,3,3-trimethylindolenine;
• e. 4-(2,4-dinitrobenzylidene)-1-ethylquinoline;
• and
• f. 4-(2,4-dinitrobenzylidene)-2,6-diphenyl-4H-pyran.