US4235537A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of testing photographic film using multicolor sensitometer
Assignee: Foresight Enterprises Inc
•
Filing: 1978-01-26
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Granted: 1980-11-25
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Expires: 1998-01-26
Abstract
Abstract The sensitivity of photographic materials is measured by a device that generates a controlled exposure of light of predetermined color characteristics. Color control is maintained by subjecting an electroluminescent light source to excitation by alternating current voltages at particular frequencies selected with reference to the light souce color response.
Inventors
- 👤 Darrell T. Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:06
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/02
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
79 words
A method of test-exposing photographic material having known color-response characteristics, comprising: applying an alternating current excitation voltage to an electroluminescent plate; establishing the frequency of said voltage from at least two distinct frequencies each corresponding to a particular color-response characteristic of said plate to excite the entire area of said plate within a color range related to the color-response characteristics of said material; and exposing said material to a pulse of a predetermined quantity of light from said plate.
Claim 2
Independent Claim
79 words
A method of test-exposing photographic material having known color-response characteristics, comprising: applying an alternating current excitation voltage to an electroluminescent plate; establishing the frequency of said voltage from at least two distinct frequencies each corresponding to a particular color-response characteristic of said plate to excite the entire area of said plate within a color range related to the color-response characteristics of said material; and exposing said material to a pulse of a predetermined quantity of light from said plate.
Claim 3
Dependent Claim
23 words
A method as defined in claim 1, wherein said pulse is controlled as an integrated quantity of light intensity with respect to time.
References Cited (Backward Citations)
US3118079A
Cited
US3332332A
Cited
US3496410A
Cited
US3698294A
Cited
US3655972A
Cited
US4080075A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-25 | 1984-05-26 | 1984-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-25 | 1988-05-26 | 1988-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-25 | 1992-05-26 | 1992-11-25 | $7700.00 | Window Closed / Lapsed |