GB1317138A - Spectrally sensitized silver halide photographic emulsions - Google Patents

Abstract

1317138 Photographic silver halide emulsions FUJI PHOTO FILM CO Ltd 15 May 1970 [17 May 1969] 3500/73 Divided out of 1316493 Heading G2C Photographic silver halide emulsions having increased sensitivity in the specific adsorption wavelength of the silver halide and which also have an enlarged spectral adsorption wavelength region, have a mean silver halide grain size smaller than 0À18 micron or have at least 95% of the silver halide grains smaller than 0À2 micron in diameter and contain at least one sensitizing dye of the formula:- wherein Z<SP>1</SP> and Z<SP>2</SP> are each O, S, Se, N-R<SP>3</SP> or N-R<SP>4</SP>, C(R<SP>5</SP>)R<SP>6</SP> or Ch=Ch (in which R<SP>3</SP> and R<SP>4</SP> are each alkyl or substituted alkyl and R<SP>5</SP> and R<SP>6</SP> may together with the carbon atom to which they are attached form a ring, or are each alkyl substituted alkyl, aryl or allyl); V<SP>1</SP>, V<SP>2</SP>, W<SP>1</SP> and W<SP>2</SP> are each hydrogen or at least one is alkyl, alkoxy, OH, phenyl or halogen, or V<SP>1</SP> and V<SP>2</SP> or W<SP>1</SP> and W<SP>2</SP> together form a fused-on benzene ring; R<SP>1</SP> and R<SP>2</SP> are each alkyl or substituted alkyl; each L is CH or C(R<SP>7</SP>) (where R<SP>7</SP> is alkyl, alkoxy, OH or halogen), the L groups may be joined to each other through a polymethylene chain or an alkyl-, alkoxy-, aryl- or hydroxyl-substituted polymethylene chain; R' and R<SP>2</SP> may each be joined to L at the α-position through a polymethylene chain to form a ring; and m is 2 or 3.