Image toners for silver halide photographic films

A black-and-white, negative-acting silver halide photographic emulsion comprising a dithio substituted toning agent having the following formula:

• ##STR34## wherein R.sub.1 and R.sub.2, independently, are selected from the group consisting of alkyl, aryl, and heterocyclic groups;
• n and m are integers from 1 to 5;
• and
• X is selected from the group consisting of O, S, --OH, and N--N(R).sub.2, wherein R is a hydrogen or alkyl group.

A black-and-white, negative-acting silver halide photographic element having improved image tone comprising a support having coated thereon at least one layer comprising a silver halide photographic emulsion comprising a dithio substituted toning agent having the following formula:

• ##STR35## wherein R.sub.1 and R.sub.2, independently, are selected from the group consisting of alkyl, aryl and heterocyclic groups;
• n is an integer from 1 to 5;
• m is an integer from 1 to 5;
• Y is a hydrocarbon;
• and
• R.sub.3 is a hydrogen or alkyl group.

A black-and-white, negative-acting photographic element having improved image tone comprising a support having coated thereon at least one layer comprising a silver halide photographic emulsion comprising a dithio substituted toning agent having the following formula:

• ##STR36## wherein R.sub.1 and R.sub.2, independently, are selected from the group consisting of alkyl, aryl, and heterocyclic groups;
• n and m are integers from 1 to 5;
• and
• X is selected from the group consisting of O, S, --OH, and N--N(R).sub.2, wherein R is a hydrogen or alkyl group.

A black-and-white, negative-acting silver halide photographic emulsion comprising a dithio substituted toning agent having the following formula:

• ##STR37## wherein R.sub.1 and R.sub.2, independently, are selected from the group consisting of alkyl, aryl and heterocyclic groups, or R.sub.1 and R.sub.2 together form a cyclic compound selected from the group consisting of 1,5-dithicyclooctane and 1,5, 9, 13-tetrathiacyclohexadecane;
• n is an integer from 1 to 5;
• m is an integer from 1 to 5;
• Y is a hydrocarbon;
• and
• R.sub.3 is a hydrogen or alkyl group.