US2833612A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Restoration of faded ink writings
Assignee: CARL E HULTMAN
•
Filing: 1957-07-22
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Granted: 1958-05-06
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Expires: 1977-07-22
Abstract
No abstract record available.
Inventors
- 👤 Lloyd H Almy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:22
CPC Classifications
C; C09; C09D; C09D11/00; C09D11/16; C09D11/17; Y; Y10; Y10S; Y10S8/00; Y10S8/916; Y10S8/919
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
62 words
IN A METHOD OF RESTORING FADED WRITINGS MADE FROM IRON INK SUSCEPTIBLE TO OXIDATION WITH CONSEQUENT COLOR FADING IN WHICH THE WRITING IS TREATED WITH AN AQUEOUS SOLUTION OF AN ALKALI METAL FERROCYANIDE OF THE GROUP CONSISTING OF NA4FE(CN)6 AND K4FE(CN)6 CONTAINING ACID AND AN ALKALI METAL HALIDE, THE IMPROVEMENT CONSISTING IN ADDING IN SAID SOLUTION AN IONIZABLE SOLUBLE ALKALINE EARTH SALT.
Claim 2
Dependent Claim
62 words
IN A METHOD OF RESTORING FADED WRITINGS MADE FROM IRON INK SUSCEPTIBLE TO OXIDATION WITH CONSEQUENT COLOR FADING IN WHICH THE WRITING IS TREATED WITH AN AQUEOUS SOLUTION OF AN ALKALI METAL FERROCYANIDE OF THE GROUP CONSISTING OF NA4FE(CN)6 AND K4FE(CN)6 CONTAINING ACID AND AN ALKALI METAL HALIDE, THE IMPROVEMENT CONSISTING IN ADDING IN SAID SOLUTION AN IONIZABLE SOLUBLE ALKALINE EARTH SALT.
References Cited (Backward Citations)
US1296858A
Cited
US2182672A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-05-05 | 1961-11-04 | 1962-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-05-05 | 1965-11-04 | 1966-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-05-05 | 1969-11-04 | 1970-05-06 | $7700.00 | Window Closed / Lapsed |