US3649280A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic elements and compositions
Assignee: Eastman Kodak Co
•
Filing: 1968-11-29
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Granted: 1972-03-14
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Expires: 1988-11-29
Abstract
Abstract A thermolabile photographic developing agent precursor which is a reaction product of an acidic silver halide developing agent, such as ascorbic acid or a hydroxy tetronic acid, with a labile organic base, such as urea, an amide or guanidine, is useful in photographic elements and/or compositions in dry processing. These developing agent precursors are activated by heat and/or alkali.
Inventors
- 👤 James R King
- 👤 Grant M Haist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:19
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/30; C; C07; C07D; C07D307/00; C07D307/02; C07D307/34; C07D307/56; C07D307/62; G03C1/00; G03C1/005; G03C1/06; G03C1/42; Y; Y10; Y10S; Y10S430/00; Y10S430/156
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
11 words
An element as in claim 1 wherein said amide is urea.
Claim 2
Dependent Claim
35 words
An element comprising a support having thereon a photographic silver halide emulsion and in said emulsion a preformed thermolabile developing agent precursor which is a reaction product of ascorbic acid with an amide or guanidine.
Claim 3
Dependent Claim
29 words
A photographic composition comprising a photographic silver salt and a preformed thermolabile photographic developing agent precursor which is a reaction product of ascorbic acid with an amide or guanidine.
Claim 4
Dependent Claim
13 words
A photographic composition as in claim 4 comprising a photographic silver halide emulsion.
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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) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |