Silver halide emulsion
AssigneeFuji Photo Film Co., Ltd.
InventorMitsuo Saitou
Life of this patent
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Abstract
A silver halide emulsion at least containing a dispersion medium and silver halide grains, in which the grains of 20% or more of the total projected areas of all the silver halide grains are substantially octahedral grains as derived from cubic grains by deleting substantially two diagonal apexes of the eight apices of the cubic grain, the outer surface of the deleted site is a {111} plane, and the main plane (the maximum flat plane of the outer surface of the grain) is a {100} plane. Since the sites of forming chemically-sensitized nuclei are defined in the emulsion grains, dispersion of latent images formed is inhibited. The emulsion has a high sensitivity and has excellent reciprocity law failure characteristics, developability and formed image quality.
Claims8
A silver halide emulsion comprising a dispersion medium and silver halide grains, wherein (i) the grains of 20% or more of the total projected area of all the silver halide grains have an octahedral shape, wherein said octahedral shape is derived from cubic grains by deleting two apices among the eight apices of the cubic grains, (ii) the outer surface of said silver halide grains having an octahedral shape comprises one triangular {111} plane at each of the deleted sites and said triangular {111} planes are parallel to one another, (iii) the main plane (the maximum flat plane of the outer surface of the grain) is a {100} plane, (iv) the edge length of said cubic grains prior to deleting the two apices is given by (y) and the edge length of the two deleted apices is given by (x), (v) (x/y) is from 0.06 to 0.65, and (vi) the apices other than said two deleted apices are not deleted, or if deleted, have an edge length (z) which satisfies the relationship 2z<x, wherein the silver halide grains each have two or more parallel twin crystal planes in the inside of the grain.
Dependencies are inferred from the claim text.