Development inhibitor releasing compounds and their use in photographic materials

Development inhibitor releasing compounds of the formula are provided wherein R1 is hydrogen or a substituent which may contain a long chain ballasting group and n is 1 or 2, or R1 may form an annelated ring, R2 is hydrogen or alkyl having 1 to 4 carbon atoms, R3 is alkyl, aryl or aralkyl, Y is hydrogen, halogen, optionally substituted phenyl, -COOR4, -COR4, or -OR4 where R4 is alkyl or aryl or a group where Z represents the atoms necessary to complete an optionally substituted 5- or 6-membered heterocyclic ring which optionally may be benzannelated. The new DIR-compounds form colorless compounds when reacted with the oxidation products of the color developing agent. They have an extremely high reactivity with the oxidation products of the color developing agent so that only small quantities of the DIR-compounds are required to produce excellent intra-image and inter-image effects of excellent speed.