US3615440A
Expired / Lapsed
US
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Novel photographic compositions and processes
Assignee: Polaroid Corp
•
Filing: 1968-10-25
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Granted: 1971-10-26
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Expires: 1988-10-25
Abstract
Abstract Substituted reductic acid compounds and preferably, tetrasubstituted reductic acid compounds are used as developing agents for silver halide emulsions in photographic processes, particularly diffusion transfer processes.
Inventors
- 👤 Stanley M Bloom
- 👤 Richard D Cramer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:04
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/30; G03C8/00; G03C8/02; G03C8/04; G03C8/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
19 words
A composition as defined in claim 1 wherein said R, R'', R'''' and R'''''' each are the radical -CH2R''''''''.
Claim 2
Dependent Claim
15 words
A composition as defined in claim 1 wherein said developing agent is tetramethyl reductic acid.
Claim 3
Independent Claim
41 words
A method of developing a silver halide emulsion which comprises treating an exposed silver halide emulsion containing a latent image with an aqueous alkaline solution containing a silver halide developing agent selected from the group consisting of compounds within the formula
Claim 4
Dependent Claim
19 words
A method according to claim 4 wherein each of said R, R'', R'''' and R'''''' are the radical -CH2R''''''''.
Claim 5
Dependent Claim
14 words
A process according to claim 4 wherein said developing agent is tetramethyl reductic acid.
Claim 6
Dependent Claim
66 words
A photographic process comprising the steps of developing a silver halide emulsion with an aqueous alkaline solution comprising a silver halide developing agent and a silver halide solvent in the presence of an image-receiving material superposed on said silver halide emulsion to form a silver transfer image on said image-receiving material, said developing agent being selected from the group consisting of compounds represented by the formula
Claim 7
Dependent Claim
18 words
A process according to claim 7 wherein each of R, R'', R'''' and R'''''' is the radical -CH2R''''''''.
Claim 8
Dependent Claim
14 words
A process according to claim 7 wherein said developing agent is tetramethyl reductic acid.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |