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US4707118A
Expired / Lapsed
US
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Method for controlling exposure in color photographic printers
Assignee: Fujifilm Holdings Corp
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Filing: 1986-12-02
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Granted: 1987-11-17
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Expires: 2006-12-02
Abstract
Abstract In conventional color photographic printers, it is emperically known that the LATD balance of RGB is substantially constant. If the exposures of three primary color components are controlled to be constant in photographic printing, standard color film negatives may be printed with excellent color balance. However, the above LATD control method is not always effective for the film negatives where a specific color is dominant, and those films are often printed with poorly balance color. The present method performs exposure control of RGB with color compensation filters controlling the color with the color compensation filter amount dependent upon factors such as the filter position, filter density, transmission factor, amount of light, etc. This method can therefore control the exposure control values at a high precision without disturbing color balance for all types of films. This method can also prevent fluctuations in density which might otherwise be entailed by the changes in color correction level so as to thereby precisely deal with changes in the sensitivity of the materials of the development process.
Inventors
- 👤 Takaaki Terashita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:09
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72; G03B27/73; G03B27/735
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
141 words
A control method for controlling the printing exposure amount in a color photographic printer which changes and controls the exposure amount in three primary colors from an exposure amount at a reference condition, and which comprises the steps of: storing characteristics of a photographic paper for printing; photographically measuring a density of a film to be printed; obtaining a desired density which is an estimated value corresponding to a printing density at the reference condition before the changing of the exposure amount using a functional formula which includes the measured density and the stored characteristics; obtaining a correction amount according to the desired density and an estimated density which is an estimated value of a printing density after the changing of the exposure amount; and controlling an exposure amount by adding or subtracting the correction amount thereto after the changing thereof.
Claim 2
Dependent Claim
141 words
A control method for controlling the printing exposure amount in a color photographic printer which changes and controls the exposure amount in three primary colors from an exposure amount at a reference condition, and which comprises the steps of: storing characteristics of a photographic paper for printing; photographically measuring a density of a film to be printed; obtaining a desired density which is an estimated value corresponding to a printing density at the reference condition before the changing of the exposure amount using a functional formula which includes the measured density and the stored characteristics; obtaining a correction amount according to the desired density and an estimated density which is an estimated value of a printing density after the changing of the exposure amount; and controlling an exposure amount by adding or subtracting the correction amount thereto after the changing thereof.
Claim 3
Dependent Claim
20 words
A control method according to claim 1, wherein the estimated density is obtained in correspondence with respective film frame pictures.
Claim 4
Dependent Claim
20 words
A control method according to claim 1, wherein the estimated density is obtained once and is stored in a memory.
Claim 5
Dependent Claim
25 words
A control method according to claim 1, wherein the characteristics are spectrum characteristics for three hues which are used in the photographic paper for printing.
Claim 6
Dependent Claim
25 words
A control method according to claim 1, wherein the characteristics are gradation characteristics for three hues which are used in the photographic paper for printing.
Claim 7
Dependent Claim
107 words
A control method for controlling the printing exposure amount in a color photographic printer which changes and controls the exposure amount in three primary colors from an exposure amount at a reference condition, and which comprises the steps of: obtaining lowered color correction values after correction of the exposure amount of the three primary colors by full color correction; obtaining a first printing density by using the full color correction; obtaining a second printing density with the lowered color correction values; and correcting exposure control values so as that the first printing density is equal to the second printing density with respect to a visual sensitivity function.
Claim 8
Dependent Claim
107 words
A control method for controlling the printing exposure amount in a color photographic printer which changes and controls the exposure amount in three primary colors from an exposure amount at a reference condition, and which comprises the steps of: obtaining lowered color correction values after correction of the exposure amount of the three primary colors by full color correction; obtaining a first printing density by using the full color correction; obtaining a second printing density with the lowered color correction values; and correcting exposure control values so as that the first printing density is equal to the second printing density with respect to a visual sensitivity function.
Claim 9
Dependent Claim
125 words
A control method for controlling the printing exposure amount in a color photographic printer which changes and controls light intensity in three primary colors by means of color compensation filters of yellow, magenta and cyan, and which comprises the steps of: obtaining first exposure amounts in the three primary colors according to values photometrically measured by photosensors; changing the exposure amounts by using a first exposure amount correcting function for full color correction; obtaining second exposure amounts in the three primary colors by using a second exposure amount correcting function for lowered color correction, which is different for respective film frame pictures, according to the first exposure amounts; and controlling the respective color compensation filters with the second exposure amounts in the three primary colors.
Claim 10
Dependent Claim
125 words
A control method for controlling the printing exposure amount in a color photographic printer which changes and controls light intensity in three primary colors by means of color compensation filters of yellow, magenta and cyan, and which comprises the steps of: obtaining first exposure amounts in the three primary colors according to values photometrically measured by photosensors; changing the exposure amounts by using a first exposure amount correcting function for full color correction; obtaining second exposure amounts in the three primary colors by using a second exposure amount correcting function for lowered color correction, which is different for respective film frame pictures, according to the first exposure amounts; and controlling the respective color compensation filters with the second exposure amounts in the three primary colors.
Claim 11
Dependent Claim
106 words
A control method for controlling the printing exposure in a color photographic printer which changes and controls the amount of light in three primary colors, and which comprises the steps of: obtaining a first function of values corresponding to weighted coefficients or specific visual sensitivity coefficients for exposure control values before said changes and said three primary colors; obtaining a second function of values corresponding to weighted coefficients or specific visual sensitivity coefficients for exposure control values after said changes and said three primary colors; and correcting the exposure control values after said changes so as that said first function is equal to said second function.
Claim 12
Dependent Claim
106 words
A control method for controlling the printing exposure in a color photographic printer which changes and controls the amount of light in three primary colors, and which comprises the steps of: obtaining a first function of values corresponding to weighted coefficients or specific visual sensitivity coefficients for exposure control values before said changes and said three primary colors; obtaining a second function of values corresponding to weighted coefficients or specific visual sensitivity coefficients for exposure control values after said changes and said three primary colors; and correcting the exposure control values after said changes so as that said first function is equal to said second function.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-11-16 | 1991-05-18 | 1991-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-16 | 1995-05-18 | 1995-11-17 | $3760.00 | Window Closed / Lapsed |
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