Patent US3765896A successfully refreshed from Google Patents.
US3765896A
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US
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Photographic element containing a light sensitive photobleachant and a colored stable 2-amino-aryl-7-oxyl-3-oxide-2-imidazoline free radical
Assignee: Eastman Kodak Co
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Filing: 1971-11-22
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Granted: 1973-10-16
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Expires: 1991-11-22
Abstract
Abstract Direct-positive photographic compositions are disclosed, the compositions including a radiation-sensitive photobleachant and a colored, stable 2-amino-aryl-1-oxyl-3-oxide-2-imidazoline free radical. When the compositions are exposed to activating radiation for the photobleachant, the colored stable-free radical is bleached or decolorized such that the exposed areas of the composition exhibit lower density and/or different coloring than the unexposed areas. Direct positive images are produced thereby. These compositions can be carried on a support to prepare photographic elements.
Inventors
- 👤 C Fox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:36
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/72; G03C1/73; G03C7/00; G03C7/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
47 words
A direct-positive photographic composition as described in claim 1 wherein, in the free radical, each of R1, R2, R3 and R4 is a lower alkyl group and each of R6 and R7 are alike and are either a methyl group, and ethyl group or a phenyl group.
Claim 2
Dependent Claim
28 words
A direct-positive photographic composition as described in claim 1 wherein said free radical and said photobleachant are included in a molar ratio of from 1:1 to about 1:10.
Claim 3
Dependent Claim
16 words
A direct-positive photographic composition as described in claim 1 and further comprising a film-forming polymeric binder.
Claim 4
Dependent Claim
23 words
A direct-positive photographic composition as described in claim 4 wherein said binder is cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate or gelatin.
Claim 5
Dependent Claim
17 words
A photographic element comprising a support having thereon a direct-positive photographic composition as described in claim 1.
Claim 6
Dependent Claim
17 words
A photographic element comprising a support having thereon a direct-positive photographic composition as described in claim 1.
Claim 7
Dependent Claim
28 words
A photographic element as described in claim 6 wherein said support comprises a porous material and said direct-positive photographic composition is imbibed into the pores of said support.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |