Patent US764853A successfully refreshed from Google Patents.
Patent US3178284A successfully refreshed from Google Patents.
US3178284A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic developer compositions
Assignee: May and Baker Ltd
•
Filing: 1961-04-03
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Granted: 1965-04-13
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Expires: 1981-04-03
Abstract
No abstract record available.
Inventors
- 👤 John David Hugh Oakley
- 👤 Field George Terence James
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:55
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/264; G03C5/266
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
73 words
A DEVELOPER CONCENTRATE COMPRISING AN AQUEOUS SOLUTION OF AT LEAST 1 GRAM PER LITRE OF 1-PHENYL-3-PYRAZOLIDONE, AT LEAST 2K GRAMS PER LITRE OF HYDROQUINONE, AT LEAST 25 GRAMS PER LITRE OF CHLOROHYDROQUINONE, AT LEAST 200 GRAMS PER LITRE OF AN ALKALI METAL SULPHITE OF THE FORMULA M2SO3 (WHERE M REPRESENTS AN ALKALI METAL ATOM), AT LEAST 10 GRAMS PER LITRE OF LACTIC ACID AND 86 TO 108.5 GRAMS PER LITRE JOF POTASSIUM HYDROXIDE.
Claim 2
Dependent Claim
73 words
A DEVELOPER CONCENTRATE COMPRISING AN AQUEOUS SOLUTION OF AT LEAST 1 GRAM PER LITRE OF 1-PHENYL-3-PYRAZOLIDONE, AT LEAST 2K GRAMS PER LITRE OF HYDROQUINONE, AT LEAST 25 GRAMS PER LITRE OF CHLOROHYDROQUINONE, AT LEAST 200 GRAMS PER LITRE OF AN ALKALI METAL SULPHITE OF THE FORMULA M2SO3 (WHERE M REPRESENTS AN ALKALI METAL ATOM), AT LEAST 10 GRAMS PER LITRE OF LACTIC ACID AND 86 TO 108.5 GRAMS PER LITRE JOF POTASSIUM HYDROXIDE.
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) | 1968-04-12 | 1968-10-12 | 1969-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-04-12 | 1972-10-12 | 1973-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-04-12 | 1976-10-12 | 1977-04-13 | $7700.00 | Window Closed / Lapsed |