The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 09, 1993
Filed:
Feb. 26, 1992
Tadaaki Tani, Kanagawa, JP;
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Abstract
A method for spectrally sensitizing silver halide emulsions is disclosed, comprising the step of adding a cyanine dye, which provides a J-band when added to silver halide emulsions, to a silver halide emulsion followed by ripening with such conditions that the relative quantum yield .phi..sub.r of spectral sensitization assumes a value of 1/2 or less of the .phi..sub.r of spectral sensitization obtained when the dye is added to the emulsion under ripening conditions of 40.degree. C. and 20 minutes from the time of addition of the dye to the emulsion until the time of coating the emulsion, and then ripening the silver halide emulsions. In one embodiment of the disclosed method, a heterocyclic compound which contains a mercapto group is added to the emulsion before the addition of the dye in an amount sufficient to increase the .phi..sub.r.