Silver halide light sensitive emulsion layer having enhanced photographic sensitivity

摘要

A photographic element comprises at least one silver halide emulsion layer in which the silver halide is sensitized with a compound of formula        Z-(L-XY)_kwherein:Z is a light absorbing group;L is a linking group containing a least oneC, N, S, or O atom; andk is 1 or 2; andXY represents a fragmentable electron donor moiety wherein:1) XY has a an oxidation potential between 0 and about 1.4 V;2) X is an electron donor group;3) Y is a leaving group other than hydrogen; and4) the oxidized form of XY undergoes a bond cleavage reaction to give the radical X^• and the leaving fragment Y. In a preferred embodiment the radical X^• has an oxidation potential of ≤ -0.7 V.