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US4639416A Expired / Lapsed US ⏱️ 0.0 years remaining

Internal latent image-type silver halide emulsion

Assignee: Fujifilm Holdings Corp
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Filing: 1984-05-11
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Granted: 1987-01-27
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Expires: 2004-05-11
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Abstract

Abstract An internal latent image-type silver halide emulsion containing core/shell type silver halide grains with a mean grain size of about 0.4 μm or less, the grains comprising a core of chemically sensitized silver halide and a shell of silver halide covering at least the light-sensitive sites of the core and the surface of the grains being chemically sensitized wherein the core is chemically sensitized to such an extent that the difference between fog density F 1 and fog density F 2 as defined herein (i.e., internal fog density) is at least 0.10. This emulsion permits the formation of good reversal images in which D max is high and D min is low and, furthermore, has a superior storage stability.

Inventors

  • 👤 Tetsuo Yoshida
  • 👤 Tadayoshi Kokubo

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 18:18
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/485; G03C1/035; G03C2001/03535; Y; Y10; Y10S; Y10S430/00; Y10S430/141

Claims Analysis

Total Claims: 12
Claim 1
Independent Claim 245 words
An internal latent image silver halide emulsion containing core/shell silver halide grains with a mean grain size of about 0.4 μm or less, said grains comprising a core of chemically sensitized silver halide and a shell of silver halide covering at least the light-sensitive sites of the core, and the surface of said grains being chemically sensitized, wherein the core is chemically sensitized to such an extent that the difference between fog density F 1 and fog density F 2 as defined below is at least 0.10, where fog density F 1 is the fog density when the internal latent image emulsion is coated in an amount (as silver) of 1.5 g/m 2 and developed with Developer D as described below at 20° C. for 13 minutes without application of imagewise exposure, not including base density; ______________________________________ Composition of Developer D ______________________________________ N--Methyl-p-aminophenol Sulfate 2.5 g L--Ascorbic Acid 10 g Sodium Metaborate 35 g Potassium Bromide 1 g Sodium Thiosulfate 3 g Water to make 1,000 ml ______________________________________ and fog density F 2 is the fog density when the internal latent image emulsion is coated in an amount (as silver) of 1.5 g/m 2 and developed with Developer E as described below at 20° C. for 13 minutes without application of imagewise exposure, not including base density ______________________________________ Composition of Developer E ______________________________________ N--Methyl-p-aminophenol Sulfate 2.5 g L--Ascoribc Acid 10 g Sodium Metaborate 35 g Potassium Bromide 1 g Water to make 1,000 ml ______________________________________
Claim 2
Dependent Claim 245 words
An internal latent image silver halide emulsion containing core/shell silver halide grains with a mean grain size of about 0.4 μm or less, said grains comprising a core of chemically sensitized silver halide and a shell of silver halide covering at least the light-sensitive sites of the core, and the surface of said grains being chemically sensitized, wherein the core is chemically sensitized to such an extent that the difference between fog density F 1 and fog density F 2 as defined below is at least 0.10, where fog density F 1 is the fog density when the internal latent image emulsion is coated in an amount (as silver) of 1.5 g/m 2 and developed with Developer D as described below at 20° C. for 13 minutes without application of imagewise exposure, not including base density; ______________________________________ Composition of Developer D ______________________________________ N--Methyl-p-aminophenol Sulfate 2.5 g L--Ascorbic Acid 10 g Sodium Metaborate 35 g Potassium Bromide 1 g Sodium Thiosulfate 3 g Water to make 1,000 ml ______________________________________ and fog density F 2 is the fog density when the internal latent image emulsion is coated in an amount (as silver) of 1.5 g/m 2 and developed with Developer E as described below at 20° C. for 13 minutes without application of imagewise exposure, not including base density ______________________________________ Composition of Developer E ______________________________________ N--Methyl-p-aminophenol Sulfate 2.5 g L--Ascoribc Acid 10 g Sodium Metaborate 35 g Potassium Bromide 1 g Water to make 1,000 ml ______________________________________
Claim 3
Dependent Claim 34 words
The silver halide emulsion of claim 1, wherein said silver halide of the core and of the shell is chemically sensitized using sulfur sensitization, reduction sensitization, noble metal sensitization or a combination of such.
Claim 4
Dependent Claim 31 words
The silver halide emulsion of claim 1, wherein the chemically sensitized silver halide of the core and of the shell is sensitized using a combination of gold sensitization and sulfur sensitization.
Claim 5
Dependent Claim 44 words
The silver halide emulsion of claim 1, wherein the chemically sensitized silver halide of the core and of the shell is sensitized at a pH of 9 or less, a pAg of 10 or less and at a temperature of 40° C. or less.
Claim 6
Dependent Claim 65 words
The silver halide emulsion of claim 1, wherein the core of chemically sensitized silver halide is doped with one or more metal ions selected from the group consisting of cadmium ions, zinc ions, thallium ions, iridium ions, iridium complex ions, rhodium ions, rhodium complex ions, iron ions or iron complex ions, in an amount of at least 10 -6 mol per mol of silver halide.
Claim 7
Dependent Claim 25 words
The silver halide emulsion of claim 1, wherein said silver halide is silver bromide, silver iodide, silver chloride, silver chlorobromide, silver bromoiodide or silver chlorobromoiodide.
Claim 8
Dependent Claim 28 words
The silver halide emulsion of claim 1, wherein said silver halide comprises at least 50 mol% of silver bromide and about 10 mol% or less of silver iodide.
Claim 9
Dependent Claim 29 words
The silver halide emulsion of claim 1, wherein the difference between fog density F 1 and fog density F 2 is at least 0.15 and not more than 0.50.
Claim 10
Dependent Claim 24 words
The silver halide emulsion of claim 1, wherein the core/shell silver halide grains have a mean grain size of about 0.05 to 0.4 μm.
Claim 11
Dependent Claim 24 words
The silver halide emulsion of claim 9, wherein the core/shell silver halide grains have a mean grain size of about 0.1 to 0.3 μm.
Claim 12
Dependent Claim 24 words
A photographic light-sensitive element comprising a support having thereon at least one layer containing the internal latent image silver halide emulsion of claim 1.

References Cited (Backward Citations)

US3317322A Cited
US3761276A Cited
US4035185A Cited
US4431731A Cited
US4444865A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1990-01-26 1990-07-28 1991-01-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1994-01-26 1994-07-28 1995-01-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1998-01-26 1998-07-28 1999-01-27 $7700.00 Window Closed / Lapsed

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