US3647296A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light-monitoring device for use with color photographic apparatus
Assignee: Pavelle Corp
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Filing: 1970-03-09
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Granted: 1972-03-07
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Expires: 1990-03-09
Abstract
Abstract Light-monitoring apparatus is disclosed for use with a color printing process in which the mean printing conditions are determined and applied to all prints. Three photoelectric transducers responsive to the primary colors are arranged to receive light from the source, after filtering, with such light being screened from the photosensitive material on which the prints are formed. The exposure times for the process are then determined by the average intensity of the light impinging upon the photocells. The photocells may also be partially responsive to light passing through the negative or transparency to correct partially for density and/or color changes from transparency to transparency.
Inventors
- 👤 John Geoffrey Long
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:42
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72; G03B27/73
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
205 words
Apparatus for monitoring the light output of a light source in a photographic color printing process wherein a plurality of prints are to be made from one or more transparencies or negatives by exposing photosensitive material to light corresponding to three primary colors for respective exposure periods, said prints being made under essentially identical conditions, with color filters being used to determine the color composition of the printing light, and wherein the intensity of the light and said color composition is subject to undesired changes during said process, the improvement comprising three photoelectric transducers, each being responsive to light corresponding to one of said primary colors, means for transmitting a portion of the light from said light source which does not pass through the transparency or negative to be reproduced to said three photoelectric transducers, said light-transmitting means being positioned with respect to said filters and light source so that said light portion passes through a filter which has been inserted into the light path, means for screening said photosensitive material from said light portion, and timing means responsive to said photoeleCtric transducers for varying each of said exposure periods depending upon the average intensity of the light impinging upon the photoelectric transducer associated therewith.
Claim 2
Dependent Claim
205 words
Apparatus for monitoring the light output of a light source in a photographic color printing process wherein a plurality of prints are to be made from one or more transparencies or negatives by exposing photosensitive material to light corresponding to three primary colors for respective exposure periods, said prints being made under essentially identical conditions, with color filters being used to determine the color composition of the printing light, and wherein the intensity of the light and said color composition is subject to undesired changes during said process, the improvement comprising three photoelectric transducers, each being responsive to light corresponding to one of said primary colors, means for transmitting a portion of the light from said light source which does not pass through the transparency or negative to be reproduced to said three photoelectric transducers, said light-transmitting means being positioned with respect to said filters and light source so that said light portion passes through a filter which has been inserted into the light path, means for screening said photosensitive material from said light portion, and timing means responsive to said photoeleCtric transducers for varying each of said exposure periods depending upon the average intensity of the light impinging upon the photoelectric transducer associated therewith.
Claim 3
Dependent Claim
27 words
Apparatus according to claim 1, including means for further coupling a portion of the light which has passed through said transparency or negative to said photoelectric transducers.
References Cited (Backward Citations)
DE1214525B
Cited
US3521952A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |