US4045228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct positive emulsions containing fogged, monodispersed silver halide grains having more than 10 mile % iodide
Assignee: Agfa Gevaert NV
•
Filing: 1973-11-20
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Granted: 1977-08-30
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Expires: 1993-11-20
Abstract
Abstract Direct positive silver halide emulsions are provided which contain fogged homodisperse silver halide grains having a silver iodide content of more than 10 mole % and at most 20 mole % relative to the total amount of silver halide. These emulsions have higher sensitivity than corresponding fogged emulsions with less silver iodide content.
Inventors
- 👤 Willy Joseph Vanassche
- 👤 Herman Alberik Pattyn
- 👤 Otto Lapp
- 👤 Sieghart Klotzer
- 👤 Erik Moisar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:13
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/485; G03C1/48515
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
86 words
Photographic material comprising at least one layer of a direct-positive radiation-sensitive emulsion having high sensitivity and good maximum density containing fogged homodisperse silver halide grains wherein at least 95% by weight of the silver halide grains of the emulsion have a diameter which is within about 40% of the mean grain diameter and wherein the silver halide of the grains has a silver iodide content of more than 10 mole % and at most about 20 mole % relative to the total amount of silver halide.
Claim 2
Dependent Claim
86 words
Photographic material comprising at least one layer of a direct-positive radiation-sensitive emulsion having high sensitivity and good maximum density containing fogged homodisperse silver halide grains wherein at least 95% by weight of the silver halide grains of the emulsion have a diameter which is within about 40% of the mean grain diameter and wherein the silver halide of the grains has a silver iodide content of more than 10 mole % and at most about 20 mole % relative to the total amount of silver halide.
Claim 3
Dependent Claim
21 words
Photographic material according to claim 1, wherein the silver iodide content is comprised between about 12 and about 20 mole %.
Claim 4
Dependent Claim
18 words
Photographic material according to claim 1, wherein the said silver halide grains have been fogged by reduction sensitisation.
Claim 5
Dependent Claim
26 words
Photographic material according to claim 3, wherein the said silver halide grains have been fogged by treatment of the silver halide grains with a reducing agent.
Claim 6
Dependent Claim
15 words
Photographic material according to claim 4, wherein said reducing agent is thiourea dioxide or tin(II)chloride.
Claim 7
Dependent Claim
27 words
Photographic material according to claim 3, wherein the silver halide grains have been fogged by silver halide precipitation or digestion in low pAg and/or high pH conditions.
Claim 8
Dependent Claim
25 words
Photographic material according to claim 3, wherein fogging also occurs in the presence of a compound of a metal that is more electropositive than silver.
Claim 9
Dependent Claim
14 words
Photographic material according to claim 7, wherein said metal compound is a gold compound.
Claim 10
Dependent Claim
17 words
Photographic material according to claim 1, wherein the silver halide grains have in their interior ripening nuclei.
Claim 11
Dependent Claim
13 words
Photographic material according to claim 1, wherein the emulsion has been sensitized spectrally.
Claim 12
Dependent Claim
84 words
Method of producing direct-positive images, which comprises image-wise exposing and subsequently surface developing a direct positive material containing fogged homodisperse silver halide grains wherein at least 95% by weight of the silver halide grains of the emulsion have a diameter which is within about 40% of the mean grain diameter and wherein the silver halide of the grains has a silver iodide content of more than 10 mole % and at most about 20 mole % relative to the total amount of silver halide.
Claim 13
Dependent Claim
84 words
Method of producing direct-positive images, which comprises image-wise exposing and subsequently surface developing a direct positive material containing fogged homodisperse silver halide grains wherein at least 95% by weight of the silver halide grains of the emulsion have a diameter which is within about 40% of the mean grain diameter and wherein the silver halide of the grains has a silver iodide content of more than 10 mole % and at most about 20 mole % relative to the total amount of silver halide.
Claim 14
Dependent Claim
21 words
Method according to claim 11, wherein development occurs by means of a viscous processing liquid comprising an alkali-soluble polymeric thickening agent.
Claim 15
Dependent Claim
11 words
Method according to claim 12, wherein said thickening agent is carboxymethylcellulose.
References Cited (Backward Citations)
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US3531290A
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US3320069A
Cited
US3647455A
Cited
US3759713A
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US3740226A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-29 | 1981-02-28 | 1981-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-29 | 1985-02-28 | 1985-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-29 | 1989-02-28 | 1989-08-30 | $7700.00 | Window Closed / Lapsed |