Photoimaging systems with cyclic hydrazides

Claim 1

A photosensitive system comprising in intimate admixture (1) at least one dye in the leuco form having one to two removable hydrogens, the removal of which forms a differently colored compound; with the proviso that when the leuco form has only one removable hydrogen and the resultant dye is cationic, there is also present a mineral acid, organic acid or acid-supplying compound which forms a salt with the leuco form of the dye, and (2) at least one photooxidant compound taken from the group of 2,4,5-triarylbiimidazolyl dimer consisting of two lophine radicals bound together by a single covalent bond, benzophenone, a para-aminophenyl ketone, a polynuclear quinone, a thioxanthenone, and mixtures thereof, the improvement being that in the presence of said admixture is at least one cyclic phenylhydrazide compound of the formula: ##STR15## wherein X may be either H 2 C< or O═C< with the proviso that when X is H 2 C<, Y is ##STR16## and when X is O═C<, Y is ##STR17## R 1 and R 2 are the same or different and are hydrogen atoms, alkyl of 1 to 4 carbon atoms, hydroxyalkyl of 1 to 4 carbon atoms; R 3 is hydrogen, alkyl of 1 to 4 carbon atoms in the ortho, meta or para positions, alkoxy of 1 to 4 carbon atoms in the ortho, meta or para positions, chloro, fluoro or bromo in the meta or para positions, sulfo in the para position, substituted alkyl, aralkoxy, and aryloxy; and R 4 is hydrogen and alkyl of 1 to 4 carbon atoms.