Patent ID: 6686142
Filing Date: 2004-02-03
Classification: G03C,Y10S

Abstract:
Chemically and spectrally-sensitized silver halide photographic emulsion having (100) cubic silver bromoiodide grains or crystals with an average edge length of from 0.2 up to 1.5 &mgr;m, wherein said grains have been spectrally sensitized in the wavelength range from 540 nm to 555 nm with at least three spectrally sensitizing dyes:a main spectrally sensitizing dye present in an amount of at least 85 mole %, a second spectrally sensitizing dye present in an amount of less than 10 mole %, and a third spectrally sensitizing dye present in an amount of at most 5 mole %, said amount being expressed in mole % based on total molar amounts of all spectrally sensitizing dyes added; characterized in that at least said main spectrally sensitizing dye is a methine dye comprising first and second nuclei joined by a substituted or unsubstituted trimethine linkage, wherein at least nuclei are both benzoxazole nuclei, said nuclei being each substituted by one halogen atom or by a methyl group in the 5- and 5â€²- or 6- and 6â€²-position respectively; the N-atom of which has a substituted or unsubstituted alkyl chain having from 1 to 4 carbon atoms and a water-soluble group; at least said third spectrally sensitizing dye is a methine dye comprising first and second nuclei joined by a substituted or unsubstituted trimethine linkage, wherein both nuclei are benzimidazole nuclei, said nuclei substituted by one or more halogen atom(s) in the 5-, 5â€²-,6- and/or 6â€²-position, or by a methyl group; the N-atoms of which having a substituted or unsubstituted alkyl chain having from 1 to 4 carbon atoms and a water-soluble group on at least on one N-atom; and in that the said second spectrally sensitizing dye is a trimethine dye comprising first and second nuclei, independently represented by a benzoxazole or a benzimidazole nucleus, at least one of them being substituted by a hydrophobic substituent, having a higher Van der Waals volume than any other hydrophobic substituent of both other spectrally sensitizing dyes.