Patent ID: 6593073
Filing Date: 2003-07-15
Classification: G03C

Abstract:
A silver halide photographic element comprising at least one silver halide emulsion layer comprising a silver halide emulsion comprising polymorphic core/shell silver halide grains wherein the core region comprises silver bromide with from about 5 to about 20% silver iodide and the shell region comprises silver bromide with about 0.1 to about 10% silver iodide and said layer contains a fragmentable electron donor compound of the formula Xâ€”Yâ€² or a compound which contains a moiety of the formula â€”Xâ€”Yâ€²; wherein said fragmentable electron donating compound is of the formulaQâ€”Xâ€”Yâ€²Aâ€”(Xâ€”Yâ€²)k (A)kâ€”Xâ€”Yâ€²Zâ€”(Xâ€”Yâ€²)k Or(Z)kâ€”Xâ€”Yâ€²wherein:Z is a light absorbing group; k is 1 or 2; A is a silver halide adsorptive group; Q represents the atoms necessary to form a chromophore comprising an amidinium-ion, a carboxyl-ion or dipolar-amidic chromophoric system when conjugated with Xâ€”Yâ€²; X is an electron donor moiety, Yâ€² is a leaving proton H or a leaving group Y, with the proviso that if Yâ€² is H a base, &bgr;, is covalently linked directly or indirectly to X; or said fragmentable electron donating compound being of the formula Xâ€”H or an electron donor which contains an â€”Xâ€”H moiety; whereinX is an electron donor moiety to which a base, &bgr;âˆ’ is directly or indirectly covalently linked, H is a hydrogen atom; 1) Xâ€”Yâ€² has an oxidation potential between 0 and about 1.4 V; and 2) the oxidized form of Xâ€”Yâ€² undergoes a bond cleavage reaction to give the radical Xâ€¢ and the leaving fragment Yâ€²; and, optionally, 3) the radical Xâ€¢ has an oxidation potential