Tellurium complexes as chemical sensitizers for silver halides
AssigneeEastman Kodak Company
InventorsKenneth James Lushington, Henry James Gysling
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Abstract
The invention is generally accomplished providing a silver halide emulsion comprising silver halide grains and a tellurium compound represented by Formula I: TeL.sub.n X.sub.2 wherein L is thiourea or substituted thiourea, n is 2 or 4, X is Cl, Br, I, OCN, SCN, SeCN, TeCN, or N.sub.3 or Formula II ##STR1## wherein X is COR, CSR, CNR.sub.2, CR, CAr, PR.sub.2, P(OR).sub.2 R is alkyl or aryl.
Claims20
A silver halide emulsion comprising silver halide grains and a tellurium compound represented by Formula I:
- TeL.sub.n X.sub.2
- wherein
- L is thiourea or substituted thiourea, or selenourea or substituted selenourea,
- n is 2 or 4,
- X is Cl, Br, I, OCN, SCN, SeCN, TeCN, or N.sub.3 or
- Formula II ##STR7## wherein X is COR, CSR, CNR.sub.2, CR, CAr, PR.sub.2, P(OR).sub.2
- R is alkyl or aryl wherein said tellurium compound is a sensitizer located on the surface of said grains.
A method of sensitizing silver halide comprising providing silver halide grains and bringing said grains into contact with a tellurium compound represented by
- Formula I:
- TeL.sub.n X.sub.2
- wherein
- L is thiourea or substituted thiourea, selenourea or substituted selenourea,
- n is 2 or 4,
- X is Cl, Br, I, OCN, SCN, SeCN, TeCN, or N.sub.3 or
- Formula II ##STR9## wherein X is COR, CSR, CNR.sub.2, CR, CAr, PR.sub.2, P(OR).sub.2
- R is alkyl or aryl to sensitize said grains.
A silver halide emulsion comprising silver halide grains and a chemical sensitizer for said silver halide grains comprising a tellurium compound represented by Formula I:
- TEL.sub.n X.sub.2
- wherein
- L is thiourea or substituted thiourea, or selenourea or substituted selenourea,
- n is 2 or 4,
- X is Cl, Br, I, OCN, SCN, SeCN, TeCN, or N.sub.3 or
- Formula II ##STR11## wherein X is COR, CSR, CNR.sub.2, CR, CAr, PR.sub.2, P(OR).sub.2
- R is alkyl or aryl, wherein said tellurium compound is located on the surface of said grain and said tellurium compound is present in an amount of between 5 and 50 .mu.mol/mol Ag.
Dependencies are inferred from the claim text.