US3761183A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for measuring color-compensation quantity for color printing
Assignee: Minolta Co Ltd
•
Filing: 1971-04-19
•
Granted: 1973-09-25
•
Expires: 1991-04-19
Abstract
Abstract The appropriate compensation quantities of a color compensation filter for use in color printing, as well as required exposure quantity, can be measured efficiently without insertion of such filters in an actual photographic enlarger. This can be accomplished by employing a device comprising a light source of standard spectrum, a means for measuring light transmitted through a color negative including three photodetectors respectively having photosensitivities in the red, green and blue spectrum ranges, operating circuits for computing each ratio between the output of a selected photoconductor and output of another or the other photodetector, and indicating means for indicating outputs of said operating circuits.
Inventors
- 👤 Y Yuasa
- 👤 M Naya
- 👤 K Tsuchiyasu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:59
CPC Classifications
G; G03; G03C; G03C7/00; G03C7/18; G03B; G03B27/00; G03B27/72; G03B27/73
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
194 words
A device for measuring the color compensation quantity for color printing comprising: a light source for projecting on a color negative a light of standard spectrum; three photo detectors for measuring the light transmitted from said light source through the color negative, respectively having photo-sensitivities in red, green and blue spectrum ranges, which ranges are defined to suit respective spectrum sensitivity characteristics of respective layers in an emulsion of a color printing paper; a first operating circuit responsive to the output of the red and green photodetectors for computing the ratio between the output of the red photo detector and the output of the green photo detector; a second operating circuit responsive to the output of the red and blue photodetectors for computing the ratio between the output of the red photo detector and the output of the blue photo detector; a pair of indicating means for indicating color compensation quantities in green and blue spectrum ranges, respectively, in response to the outputs of said first and second operating circuits; and an exposure time indicator operatively coupled to a photo detector sensitive in the red spectrum range to the light from said light source.
Claim 2
Independent Claim
194 words
A device for measuring the color compensation quantity for color printing comprising: a light source for projecting on a color negative a light of standard spectrum; three photo detectors for measuring the light transmitted from said light source through the color negative, respectively having photo-sensitivities in red, green and blue spectrum ranges, which ranges are defined to suit respective spectrum sensitivity characteristics of respective layers in an emulsion of a color printing paper; a first operating circuit responsive to the output of the red and green photodetectors for computing the ratio between the output of the red photo detector and the output of the green photo detector; a second operating circuit responsive to the output of the red and blue photodetectors for computing the ratio between the output of the red photo detector and the output of the blue photo detector; a pair of indicating means for indicating color compensation quantities in green and blue spectrum ranges, respectively, in response to the outputs of said first and second operating circuits; and an exposure time indicator operatively coupled to a photo detector sensitive in the red spectrum range to the light from said light source.
Claim 3
Dependent Claim
199 words
A device as defined in claim 1, wherein each of said operating circuits comprises: logarithm-converting circuits respectively connected to the red photo detector and a respective one of said blue and green photo detectors; a differential amplifier, one input terminal of which is connected to the logarithm-converting circuit that is connected to receive the output of the red photo detector, and the other input terminal of which is connected to receive the output of said respective one of said photo detectors; and a voltage generator which is connected between one of said logarithm-converting circuits and said one input terminal of the differential amplifier and comprises a manually operable member for changing the voltage of the voltage generator; and wherein each of said indicating means comprises: a servo system which, in response to the output of said differential amplifier, adjusts the output of said voltage generator in a manner so that the sum of the output of the voltage generator and the output of one of said logarithm-converting circuits is equalized with the output of the other of said logarithm-converting circuits; and an indicating member which indicates the color compensation quantity in response to the adjustment of the voltage generator.
Claim 4
Dependent Claim
65 words
A device as defined in claim 2, wherein each voltage generator comprises an electric power source, a first potentiometer having both ends thereof connected across the power source and being connected to the red logarithm-convertinG circuit with a movable contact thereof, and a second potentiometer having both its ends connected across the power source and having a movable contact connected to the corresponding differential amplifier.
Claim 5
Dependent Claim
33 words
A device as claimed in claim 3, wherein said movable contact of said second potentiometer is interlocked with said servo system and said first potentiometer is so constructed as to be manually adjustable.
Claim 6
Dependent Claim
55 words
A device as claimed in claim 4, wherein each logarithm-converting circuit, for each of the red, green and blue spectrum ranges, comprises a logarithm-converting diode member connected to the collector of a transistor, and wherein one of said photo detectors consists of at least two-series-connected photo conductive cells connected to the emitter of said transistor.
References Cited (Backward Citations)
US3527540A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |