Dihydrazides

A photographic silver halide material which comprises at least one silver halide emulsion layer, wherein at least one layer of said material comprises at least one hydrazide having the formula:

• B--(A.sup.+)--C G.sup.- ;
• or
• B--(A.sup.++)--C 2G.sup.-
• where B and C are the same or different and have the general structure I:
• ##STR78## where R.sub.1 is hydrogen, alkyl, alkoxy or a blocking group selected from the group consisting of:
• ##STR79## wherein R.sub.5 and R.sub.6 are independently selected from the group consisting of hydrogen, alkyl, aminoalkyl, alkylaminoalkyl, acylamino alkyl, alkylsulphonylaminoalkyl, arylsulphonylaminoalkyl, trialkylammoniumalkyl, hydroxyalkyl, haloalkyl, cycloalkyl, alkoxyalkyl, polyethyleneoxy, aryl, aralkyl, and a heterocyclic ring;
• or
• wherein R.sub.5 and R.sub.6 taken together can form a heterocyclic ring which optionally contains at least one unsaturated bond;
• R.sub.7 and R.sub.8 are independently selected from the group consisting of hydrogen, alkyl, aralkyl, hydroxy, alkoxy, aryloxy, haloalkoxy, aralkoxy, alkoxyalkoxy, hydroxyalkyl, hydroxyalkoxy, acylamino, alkyl-sulphonylamino, aryl-sulphonylamino and halogen;
• m is 1 or 2;
• and
• wherein R.sub.2 and R.sub.3 are independently hydrogen, alkyl, alkoxy, aralkyl, aralkoxy, hydroxyalkyl and halogen;
• or R.sub.2 and R.sub.3 taken together can form a saturated or unsaturated carbocyclic ring;
• I is 0 or 1;
• j is 0 or 1;
• k is 0 or 1;
• and G.sup.- is a negatively charged ion, L is a linking group;
• X is C or SO and Y is O or S;
• wherein when X is SO then Y is O;
• wherein A.sup.+ is an activity regulating group having the formula:
• ##STR80## where Z denotes the elements necessary to form a 5-membered heterocyclic ring;
• or
• wherein A.sup.++ is an activity regulating group having the formula:
• ##STR81## wherein R.sub.18 and R.sub.19, are linked together to form a ring;
• R.sub.20 and R.sub.21 are the same or different and are alkyl groups;
• or
• R.sub.20, and R.sub.21 are linked together to form a bicyclic ring system;
• wherein U is a divalent aliphatic radical, a divalent aromatic radical, a divalent aralkylene radical, a divalent aliphatic radical containing heteroatoms, or a divalent aromatic radical containing heteroatoms;
• where the heteroatoms are oxygen, nitrogen or sulfur;
• and
• n is 1 or 2 and p is 0 or 1.