US3622332A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic process with improved activator composition
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1968-04-19
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Granted: 1971-11-23
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Expires: 1988-04-19
Abstract
Abstract An improved photographic process for developing a photographic element having a silver halide emulsion layer with silver halide developing agents disposed therein or contiguous thereto as a separate layer comprising (1) exposing said photographic element and (2) applying to the exposed element an alkaline activator composition containing a small amount of a thiosulfate, preferably an alkali or alkaline earth metal or ammonium thiosulfate, having a concentration of from 2 to 20 grams per liter. It is believed that the thiosulfate causes unexposed silver halide to dissolve and plate on the image area simultaneously with chemical development, thereby creating a blue-black image tone of increased maximum density and sharpness.
Inventors
- 👤 John R Kane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:26
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/262
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
17 words
An improvement of claim 1 wherein said alkaline solution has a pH of at least about 10.5.
Claim 2
Dependent Claim
25 words
An improvement of claim 2 wherein said thiosulfate is selected from the group consisting of alkali metal thiosulfates, alkaline earth metal thiosulfates, and ammonium thiosulfate.
Claim 3
Dependent Claim
11 words
An improvement of claim 3 wherein said thiosulfate comprises sodium thiosulfate.
Claim 4
Dependent Claim
41 words
An improvement of claim 4 wherein said alkaline solution comprises an aqueous solution of said sodium thiosulfate and a alkaline material selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and mixtures thereof with sodium sulfite.
Claim 5
Dependent Claim
22 words
An improvement of claim 5 wherein the developing agent is a member selected from the group consisting of hydroquinone and substituted hydroquinones.
Claim 6
Dependent Claim
19 words
An improvement of claim 1 wherein said alkaline solution comprises an aqueous solution of sodium hydroxide and a thiosulfate.
Claim 7
Dependent Claim
21 words
An improvement of claim 1 wherein said alkaline solution comprises an aqueous solution of sodium hydroxide sodium sulfite and sodium thiosulfate.
Claim 8
Dependent Claim
100 words
In a process for photographic reproduction comprising: a. exposing a photographic element comprising a light-sensitive silver halide emulsion having a silver halide developing agent therein or in an adjacent layer in intimate contact with said silver halide emulsion; b. subsequently applying an alkaline activator solution having a pH of at least about 9 to said photographic element to develop a photographic image therein; and c. subsequently contacting said photographic element with a fixing solution, the improvement comprising incorporating into the activator solution about 2 to about 10 grams per liter of a thiosulfate to increase image density in light-exposed areas.
Claim 9
Dependent Claim
17 words
A process of claim 9 wherein said alkaline Solution has a pH of at least about 10.5.
Claim 10
Dependent Claim
25 words
A process of claim 10 wherein said thiosulfate is selected from the group consisting of alkaline metal thiosulfates, alkaline earth metal thiosulfates and ammonium thiosulfate.
Claim 11
Dependent Claim
11 words
A process of claim 11 wherein said thiosulfate comprises sodium thiosulfate.
Claim 12
Dependent Claim
39 words
A process of claim 12 wherein said solution comprises an aqueous solution of sodium thiosulfate and an alkaline material selected from the group consisting of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate and mixtures thereof with sodium sulfite.
Claim 13
Dependent Claim
12 words
A process of claim 13 wherein said alkaline material comprises sodium hydroxide.
Claim 14
Dependent Claim
18 words
A process of claim 13 wherein said alkaline material comprises a mixture of sodium hydroxide and sodium sulfite.
Claim 15
Dependent Claim
11 words
A process of claim 11 wherein said thiosulfate comprises ammonium thiosulfate.
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) | 1974-11-22 | 1975-05-24 | 1975-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-22 | 1979-05-24 | 1979-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-22 | 1983-05-24 | 1983-11-23 | $7700.00 | Window Closed / Lapsed |