Core/shell emulsions with enhanced photographic response

This invention relates to the use of a fragmentable electron donor with core/shell, light-sensitive, silver halide emulsions. A silver halide photographic element comprises at least one silver halide emulsion layer comprising a silver halide emulsion comprising core/shell silver halide grains wherei...

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Bibliographische Detailangaben
Hauptverfasser: Eikenberry, Jon N, Chang, Yun C
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:This invention relates to the use of a fragmentable electron donor with core/shell, light-sensitive, silver halide emulsions. A silver halide photographic element comprises at least one silver halide emulsion layer comprising a silver halide emulsion comprising 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 X-Y′ or a compound which contains a moiety of the formula -X-Y′;whereinX is an electron donor moiety, Y′ is a leaving proton H or a leaving group Y, with the proviso that if Y′ is a proton, a base, , is covalently linked directly or indirectly to X, and wherein:1) X-Y′ has an oxidation potential between 0 and about 1.4 V; and2) the oxidized form of X-Y′ undergoes a bond cleavage reaction to give the radical X and the leaving fragment Y′;and, optionally,3) the radical X has an oxidation potential −0.7V.