PHOTOGRAPHIC SYSTEM

摘要

There is described a photographic system wherein development of an exposed photosensitive element with an aqueous alkaline photographic developing composition is effected in the presence of a compound represented by the formula wherein R is -OH, -OR4, -NH2 -NHR5 or -NR4R6; R1 is hydrogen, -NH2, alkyl, substituted alkyl, aryl or substituted aryl; R2 and R3 each independently is hydrogen, alkyl, aralkyl or aryl; R4 is a protecting group which can be removed in the presence of a base; R5 is an activating group which can render the neighboring hydrogen atom acidic; R6 is an electron withdrawing group which is capable of stabilizing the negative charge on the nitrogen atom which is produced upon removal of R4 upon contact with alkali; and PHOTO is a photographically useful group. The compounds provide controlled release of the photographically useful group by a base-catalyzed elimination when contacted by the aqueous aklaline processing composition.