EP0136542A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Color printing control using halftone control areas
Assignee: Kollmorgen Corp
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Filing: 1984-08-30
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Granted: —
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Expires: 2004-08-30
Abstract
Abstract In a multi-color printing process, measurements of the optical density of two different three-color halftone control areas are used to calculate dot gain and solid density of the cyan, magenta and yellow images. Since no single-color solid control targets are used, control targets may be hidden or camouflaged in a border or logo in the final printed product. The two control targets can consist of light and dark near-neutral gray balance targets. Alternatively, two different three-color half-tone regions of the printed image can be used as control areas, eliminating the need for separate control targets. Densitometers having blue, green and red filters use the two three-color halftone control areas to provide density measurements which are used by a computer to calculate the densities of cyan, magenta and yellow halftone images. The computer then calculates the dot gain and solid density of the process inks, which are displayed to a pressman who can make appropriate adjustments to the printing process.
Inventors
- 👤 Albert J. Benoit
- 👤 Dudley M. Boden
- 👤 David G. Decker
- 👤 Stanley J. Kishner
- 👤 Robert D. Van Arsdell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 06:52
CPC Classifications
B; B41; B41F; B41F33/00; B41F33/0036; G; G01; G01J; G01J3/00; G01J3/46; G01J3/50; G01J3/51
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
134 words
In multi-color printing a method of determining the solid density and the amount of dot gain of each process color image, comprising the steps of printing two different three-color halftone control areas, each consisting of overprinted cyan, magenta and yellow halftones; measuring with a densitometer the blue, green and red optical densities of both control areas; calculating the densities of the halftones of cyan, magenta and yellow ink from the blue, green and red densities of the first control area; calculating the densities of the halftones of cyan, magenta and yellow ink from the blue, green and red densities of the second control area; and calculating the solid densities and dot gains of the cyan, magenta and yellow images from the densities of the first and second halftones of cyan, magenta and yellow, respectively.
Claim 2
Dependent Claim
134 words
In multi-color printing a method of determining the solid density and the amount of dot gain of each process color image, comprising the steps of printing two different three-color halftone control areas, each consisting of overprinted cyan, magenta and yellow halftones; measuring with a densitometer the blue, green and red optical densities of both control areas; calculating the densities of the halftones of cyan, magenta and yellow ink from the blue, green and red densities of the first control area; calculating the densities of the halftones of cyan, magenta and yellow ink from the blue, green and red densities of the second control area; and calculating the solid densities and dot gains of the cyan, magenta and yellow images from the densities of the first and second halftones of cyan, magenta and yellow, respectively.
Claim 3
Dependent Claim
21 words
The method as claimed in claim 1, characterized in that the two different three-color halftone control areas are both control targets.
Claim 4
Dependent Claim
24 words
The method as claimed in claim 2, characterized in that the said control targets consist of one light and one dark near-neutral control target.
Claim 5
Dependent Claim
22 words
The method as claimed in claim 1, characterized in that the three different three-color halftone control areas are in the printed image.
Claim 6
Dependent Claim
31 words
The method as claimed in claim 3, characterized in that the dark near-neutral target comprises balanced cyan, magenta and yellow halftones, none of which exceed a relative dot area of 75%.
Claim 7
Dependent Claim
49 words
The method as claimed in claim 3, characterized in that the light near-neutral target comprises balanced cyan, magenta and yellow halftone with relative dot areas between 10% and 40% and the dark near-neutral target comprises balanced cyan, magenta and yellow halftones with relative dot areas between 40 and 75%.
Claim 8
Independent Claim
22 words
The method as claimed in one of claims 1 to 4, characterized in that the densitometer is mounted on the printing press.
Claim 9
Dependent Claim
22 words
The method as claimed in claim 2, characterized in that the two three-color halftone control targets are the only control targets printed.
Claim 10
Dependent Claim
22 words
The method as claimed in claim 3, characterized in that the light and dark near-neutral targets are the only control targets printed.
Claim 11
Independent Claim
24 words
The method as claimed in one of claims 1 to 4, characterized in that the printing press operates according to the offset lithographic technique.
Claim 12
Independent Claim
26 words
The method as claimed in one of claims 1 to 4, characterized in that the densitometer optical filters have bandwidths that do not exceed 30 nm.
Claim 13
Independent Claim
44 words
The method as claimed in one of claims 1 to 4, characterized in that the dot gains and solid densities are calculated according to and respectively, where the subscripts "1" and "2" refer to the first and second halftones, respectively, for each process color.
Claim 14
Independent Claim
38 words
The method as claimed in one of claims 1 to 4, characterized in that the dot gains are calculated by evaluating the expression and finding the values of dot gain corresponding to said evaluation via a calibration curve.
Claim 15
Dependent Claim
112 words
In multi-color printing, a method of calculating the solid density and dot gain of each process color from measurements of the blue, green and red densities of a first and a second three-color halftone control target, comprising the steps of calculating the densities of the halftones of cyan, magenta and yellow ink from the blue, green and red densities of the first three-color halftone control target, and the densities of the halftones of cyan, magenta and yellow ink from the red, green and blue densities of the second three-color halftone control target; and calculating the solid densities and dot gains of the first and second halftones of cyan, magenta and yellow, respectively.
Claim 16
Dependent Claim
112 words
In multi-color printing, a method of calculating the solid density and dot gain of each process color from measurements of the blue, green and red densities of a first and a second three-color halftone control target, comprising the steps of calculating the densities of the halftones of cyan, magenta and yellow ink from the blue, green and red densities of the first three-color halftone control target, and the densities of the halftones of cyan, magenta and yellow ink from the red, green and blue densities of the second three-color halftone control target; and calculating the solid densities and dot gains of the first and second halftones of cyan, magenta and yellow, respectively.
Claim 17
Dependent Claim
29 words
The method as claimed in claim 14, characterized in that the first and second three-color halftone control targets consist of one light and one dark near-neutral control target, respectively.
Claim 18
Dependent Claim
64 words
In single-color printing, a method of calculating dot gain from measurements of the densities of a first and second halftone comprising the steps of evaluating the expression in the equation where R is the reflectance of the lighter halftone, and R D is the reflectance of the darker halftone; and finding the value of dot gain corresponding to said evaluation on a calibration curve.
Claim 19
Dependent Claim
64 words
In single-color printing, a method of calculating dot gain from measurements of the densities of a first and second halftone comprising the steps of evaluating the expression in the equation where R is the reflectance of the lighter halftone, and R D is the reflectance of the darker halftone; and finding the value of dot gain corresponding to said evaluation on a calibration curve.
References Cited (Backward Citations)
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