Photographic silver halide elements containing optical brightening water-soluble interpolymers

DETAILED DESCRIPTION We claim: 1.
A photographic element containing at least one light sensitive silver halide layer and from about 0.
05 grams to about 5.
0 grams per square foot of support of an optical brightening interpolymer having the formula: ##STR25## wherein L is a linking group selected from the group consisting of CONH, O, COO, ##STR26## S, SO.
sub.
2 and ##STR27## R.
sup.
1 is an optical brightener moiety; R is H or alkyl containing from 1 to 4 carbon atoms; R.
sup.
2 is an anionic solubilizing group selected from the groups consisting of COOM, SO.
sub.
3 M, OSO.
sub.
3 M, COOR.
sup.
4 OSO.
sub.
3 M, PO.
sub.
3 and PO.
sub.
4, wherein M is H or an alkali metal and R.
sup.
4 is alkylene containing from 1 to 4 carbon atoms; R.
sup.
3 is a unit derived from a copolymerizable ethylenically unsaturated monomer; x is from 0.
25 to 50 mole percent, y is from 5 to 99 mole percent and z is from 0 to 90 mole percent of the interpolymer.
2.
The photographic element of claim 1 wherein the interpolymer is in a hydrophilic colloid layer.
3.
The photographic element of claim 1 wherein the interpolymer is in a gelatin layer.
4.
The photographic element of claim 1 wherein the optical brightener moiety is selected from the group consisting of coumarins, stilbenes, thiophenes and benzoxazoles.
5.
The photographic element of claim 1 wherein x is from 2 to 25 mole percent and y is from 10 to 75 mole percent of the interpolymer.
6.
The photographic element of claim 1 wherein R.
sup.
1 comprises from about 1 to about 50 percent by weight of the interpolymer.
7.
The photographic element of claim 1 wherein R.
sup.
3 has the formula: ##STR28## wherein A is H or alkyl containing from 1 to 6 carbon atoms and B is COOR.
sup.
5, COR.
sup.
5, CN, or ##STR29## wherein R.
sup.
5 is alkyl containing from 1 to 6 carbon atoms.
8.
A photographic element containing at least one light sensitive silver halide layer and from about 0.
05 grams to about 5.
0 grams per square foot of support of an optical brightening interpolymer having the formula: ##STR30## wherein x is from 0