US2969709A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic negative-positive conversion and correction of gradation curves of color extractions
Assignee: Dr-Ing Rudolf Hell KG
•
Filing: 1957-07-31
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Granted: 1961-01-31
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Expires: 1977-07-31
Abstract
No abstract record available.
Inventors
- 👤 Zeyen Fritz-Otto
- 👤 Springstein Karl-August
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:31
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6027; H04N1/40; H04N1/407; H04N1/4076; H04N1/4078
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2469935A
Cited
US2692825A
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US2480424A
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US2499039A
Cited
US2565399A
Cited
US2652327A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-01-31 | 1964-08-01 | 1965-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-01-31 | 1968-08-01 | 1969-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-01-31 | 1972-08-01 | 1973-01-31 | $7700.00 | Window Closed / Lapsed |