Lightsensitive silver halide photographic emulsion, silver halide photographic lightsensitive material containing the same, and method of enhancing sensitivity of lightsensitive silver halide photographic emulsion
AssigneeFuji Photo Film Co., Ltd.
InventorKiyoshi Morimoto
Life of this patent
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Abstract
A lightsensitive silver halide photographic emulsion comprises silver halide grains, a sensitizing dye having a given maximum absorption wavelength and an organic compound exhibiting no absorption in a visible light region. The addition amount of the organic compound is in the range of 1 to 50 mol % based on the sensitizing dye, and a maximum absorption wavelength of the photographic emulsion exhibited by the sensitizing dye in the presence of the organic compound is at least 2 nm shorter than the maximum absorption wavelength exhibited by the sensitizing dye in the absence of the organic compound.
Claims14
A lightsensitive silver halide photographic emulsion comprising silver halide grains;
- a sensitizing dye having a given maximum absorption wavelength;
- and an organic compound exhibiting no absorption in a visible light region, wherein the addition amount of the organic compound is in the range of 1 to 50 mol % based on the sensitizing dye, and a maximum absorption wavelength of the photographic emulsion exhibited by the sensitizing dye in the presence of the organic compound is at least 2 nm shorter than the given maximum absorption wavelength exhibited by the sensitizing dye in the absence of the organic compound, wherein 50% or more of the total projected area of the silver halide grains are occupied by tabular silver halide grains each having (111) faces as parallel main planes;
- being hexagonal grain whose ratio of length of the longest side to the shortest side is 2 or less;
- having at least one epitaxial junction portion per grain at an apex portion and/or a side face portion and/or a main plain portion thereof;
- and having a silver halide composition of silver iodobromide or silver chloroiodobromide whose silver chloride content is less than 10 mol %.
A lightsensitive silver halide photographic emulsion comprising silver halide grains and a sensitizing dye, wherein at least one compound represented by the following general formula (1) is contained in an amount of 1 to 50 mol % based on the sensitizing dye:
- wherein Q represents a N or P atom;
- each of R1, R2, R3 and R4 represents an alkyl, an aryl or a heterocycle, provided that two of R1, R2, R3 and R4 may be bonded with each other to thereby form a saturated ring, or three of R1, R2, R3 and R4 may cooperate with each other to thereby form an unsaturated ring;
- and X represents an anion group, provided that X does not exist in the event of an intramolecular salt, wherein 50% or more of the total projected area of the silver halide grains are occupied by tabular silver halide grains each having (111) faces as parallel main planes;
- being hexagonal grain whose ratio of length of the longest side to the shortest side is 2 or less;
- having at least one epitaxial junction portion per grain at an apex portion and/or a side face portion and/or a main plain portion thereof;
- and having a silver halide composition of silver iodobromide or silver chloroiodobromide whose silver chloride content is less than 10 mol %.
A method of enhancing a sensitivity of a lightsensitive silver halide emulsion comprising a sensitizing dye having a given maximum absorption wavelength, wherein the method comprises:
- adding an organic compound exhibiting no absorption in a visible light region and capable of causing the maximum absorption wavelength of the sensitizing dye to shift toward a shorter wavelength by at least 2 nm.
Dependencies are inferred from the claim text.