EP0533593A2
Expired / Lapsed
EP
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A technique for generating additional colors in a halftone color image through use of overlaid primary colored halftone dots of varying size
Assignee: Eastman Kodak Co
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Filing: 1992-09-07
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Granted: —
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Expires: 2012-09-07
Abstract
Abstract A technique for use in a direct digital color proofing (DDCP) system (500) for printing a "modelling" color(s) in a halftone color proof image such that the modelling color simulates a ("special") color that does not lie within a gamut of colors reproducible through only primary color (e.g. cyan, magenta, yellow and black) halftone printing. Specifically, a wide range of such modelling colors can be produced by independently and appropriately setting dot size, particularly in combination with solid area density, for the halftone dots (110, 120, 130, 140) produced for different primary colors and then printing the resulting dots on an overlaid dot-on-dot basis with proper registration. Appropriate dot gain and density look-up tables (230, 720; 240, 940) are respectively used to transform continuous tone separation values and bit-mapped data to vary dot size and solid area density of these halftone dots for each such primary color prior to printing these dots using a proofing engine. A unique set of tables is used to produce each different modelling color.
Inventors
- 👤 Robert Vanselow c/o Eastman Kodak Company Barry
- 👤 Joseph Hayes c/o Eastman Kodak Company Ambro
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 11:13
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/52; H04N1/40; H04N1/405; H04N1/4055
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
197 words
A method of generating a desired color in an output image from a plurality of different colorants, said output image being a halftone depiction of a continuous tone (contone) input image, the method comprising the steps of: obtaining data representing a plurality of primary colored contone separations of said input image, each of said separations having incoming contone values wherein corresponding ones of said incoming contone values for all of said separations collectively define a region in the output image that is to contain the desired color; generating, in response to each one of the incoming contone values in each of said separations, a halftone dot wherein size and solid area density of the dot are pre-defined functions of the one incoming contone value and a separation color associated therewith so as to form a plurality of component halftone dots; printing, in said output image, spatially corresponding ones of said component halftone dots, each from a different corresponding one of said separations and with a corresponding one of said colorants, on a dot-on-dot basis in a pre-defined order and with a pre-defined registration thereamong so as to form composite halftone dots which collectively depict said desired color.
Claim 2
Dependent Claim
115 words
The method in claim 1 wherein said generating step comprises the steps of: modifying the incoming contone values contained in each one of the separations in accordance with a pre-defined dot gain relationship in order to yield corresponding modified contone values, wherein said modified contone values contain a pre-determined variation in dot gain with respect to corresponding ones of said incoming contone values; and converting each of said modified contone values for each one of said separations into a halftone dot having a pre-defined solid area density value so as to form said component dots for said one separation, wherein said solid area density value is a predefined function of a separation color associated therewith.
Claim 3
Dependent Claim
44 words
The method in claim 2 wherein the printing step comprises the step of overlaying a spatially corresponding one of said component halftone dots from each of said separations on a concentric basis in order to form a corresponding one of the composite halftone dots.
Claim 4
Dependent Claim
15 words
The method in claim 3 wherein each of said colorants is a different primary color.
Claim 5
Dependent Claim
16 words
The method in claim 4 wherein said different colorants are cyan, magenta and yellow-and black colorants.
Claim 6
Dependent Claim
66 words
The method in claim 3 wherein said incoming contone values modifying step comprises the step of applying each of said incoming contone values for said one separation through a first look-up table in order to produce corresponding ones of said modified contone values, said look-up table containing stored values that collectively define a pre-defined dot gain function for the separation color associated with said one separation.
Claim 7
Dependent Claim
73 words
The method in claim 6 wherein said first look-up table coraprises a plurality of separate dot gain look-up tables, wherein each one of the plurality of dot gain look-up tables stores a pre-defined dot gain function for a different separation color; and wherein said incoming contone values applying step comprises the step of routing each one of the incoming contone values for said one separation through the dot gain look-up table associated therewith.
Claim 8
Dependent Claim
42 words
The method in claim 7 wherein said applying step further comprises the step of reading, prior to modifying any of said incoming contone values, each of said dot gain look-up tables from a memory so as to form said first look-up table.
Claim 9
Dependent Claim
87 words
The method in claim 3 wherein said modified contone values converting step comprises the step of varying intensity levels of a writer used to print each of said component halftone dots associated with said one separation in accordance with a pre-defined solid area density relationship, wherein the pre-defined solid area density relationship characterizes an exposure level for each writing spot that is to form said component halftone dot based on whether said each writing spot is to be darkened or not and the separation color associated therewith.
Claim 10
Dependent Claim
62 words
The method in claim 9 wherein said varying step comprises the step of: applying each bit-mapped value for each of said component halftone dots through a second look-up table in order to produce corresponding ones of the intensity levels, said second look-up table containing stored values for the predefined solid area density relationship for the separation color associated with said one separation.
Claim 11
Dependent Claim
74 words
The method in claim 10 wherein said second look-up table comprises a plurality of separate solid area density look-up tables wherein each of the plurality of solid area density look-up tables stores a pre-defined solid area density relationship for a different separation color; and wherein the bit-mapped values applying step comprises the step of.& routing each one of the bit-mapped values for said one separation through the solid area density look-up table associated therewith.
Claim 12
Dependent Claim
100 words
Use of the method as defined in any of the preceeding claims in a direct digital color proofing system for generating a color halftone proof image from in-coming digitized prepress continuous tone (contone) data for an input image, said system having means for processing the incoming prepress contone data to yield screened primary colored halftone separation data representing halftone separations that are to collectively form the proof image, a marking engine for writing each of said halftone separations with proper registration so as to form said proof image, and control means connected to said processing means and said marking engine.
Claim 13
Dependent Claim
199 words
Apparatus for generating a desired color in an output image from a plurality of different colorants, said output image being a halftone depiction of a continuous tone (contone) input image, the apparatus comprising. means for obtaining data representing a plurality of primary colored contone separations of said input image, each of said separations having incoming contone values wherein corresponding ones of said incoming contone values for all of said separations collectively define a region in the output image that is to contain the desired color; means for generating, in response to each one of the incoming contone values in each of said separations, a halftone dot wherein size and solid area density of the dot are pre-defined functions of the one incoming contone value and a separation color associated therewith so as to form a plurality of component halftone dots; means for printing, in said output image, spatially corresponding ones of said component halftone dots, each from a different corresponding one of said separations and with a corresponding one of said colorants, on a dot-on-dot basis in a pre-defined order and with a pre-defined registration thereamong so as to form composite halftone dots which collectively depict said desired color.
Claim 14
Dependent Claim
116 words
The apparatus in claim 13 wherein said generating raeans comprises: means for modifying the incoming contone values contained in each one of the separations in accordance with a pre-defined dot gain relationship in order to yield corresponding modified contone values, wherein said modified contone values contain a predetermined variation in dot gain with respect to corresponding ones of said incoming contone values; and means for converting each of said modified contone values for each one of said separations into a halftone dot having a pre-defined solid area density value so as to form said component dots for said one separation, wherein said solid area density value is a pre-defined function of a separation color associated therewith.
Claim 15
Dependent Claim
40 words
The apparatus in claim 14 wherein the printing means overlays a spatially corresponding one of said component halftone dots from each of said separations on a concentric basis in order to form a corresponding one of the composite halftone dots.
Claim 16
Dependent Claim
15 words
The apparatus in claim 15 wherein each of said colorants is a different primary color.
Claim 17
Dependent Claim
17 words
The apparatus in claim 16 wherein said different colorants are cyan, magenta and yellow and black colorants.
Claim 18
Dependent Claim
67 words
The apparatus in claim 15 wherein said incoming contone values modifying means comprises: a first look-up table containing stored values that collectively define a pre-defined dot gain function for the separation color associated with said one separation; and means for applying each of said incoming contone values for said one separation through the first look-up table in order to produce corresponding ones of said modified contone values.
Claim 19
Dependent Claim
72 words
The apparatus in claim 18 wherein said first look-up table comprises a plurality of separate dot gain look-up tables, wherein each one of the plurality of dot gain look-up tables stores a pre-defined dot gain function for a different separation color; and wherein said incoming contone values applying means comprises means for routing each one of the incoming contone values for said one separation through the dot gain look-up table associated therewith.
Claim 20
Dependent Claim
86 words
The apparatus in claim 15 wherein said modified contone values converting means comprises means for varying intensity levels of a writer used to print each of said component halftone dots associated with said one separation in accordance with a pre-defined solid area density relationship, wherein the pre-defined solid area density relationship characterizes an exposure level for each writing spot that is to form said component halftone dot based on whether said each writing spot is to be darkened or not and the separation color associated therewith.
Claim 21
Dependent Claim
62 words
The apparatus in claim 20 wherein said varying means comprises: a second look-up table containing stored values for the pre-defined solid area density relationship for the separation color associated with said one separation; and means for applying each bit-mapped value for each of said component halftone dots through the second look-up table in order to produce corresponding ones of the intensity levels.
Claim 22
Dependent Claim
73 words
The apparatus in claim 21 wherein said second look-up table comprises a plurality of separate solid area density look-up tables wherein each of the plurality of solid area density look-up tables stores a pre-defined solid area density relationship for a different separation color; and wherein the bit-mapped values applying means comprises means for routing each one of the bit-mapped values for said one separation through the solid area density look-up table associated therewith.
Claim 23
Dependent Claim
102 words
A direct digital color proofing system for generating a color halftone proof image from incoming digitized pre-press continuous tone (contone) data for an input image, said system having means for processing the incoming pre-press contone data to yield screened primary colored halftone separation data representing halftone separations that are to collectively form the proof image, a marking engine for writing each of said halftone separations with proper registration so as to form said proof image, and control means connected to said processing means and said marking engine, wherein said system comprises an apparatus as defined in any of claims 13 to 22.
Claim 24
Dependent Claim
35 words
The system as defined in claim 23 when appendant to claim 15 wherein the marking engine is a sublimation dye transfer laser printer and said colorants comprise cyan, magenta, yellow and black colored donor sheets.
Claim 25
Dependent Claim
35 words
The system as defined in claim 23 when appendant to claim 19 wherein the marking engine is a sublimation dye transfer laser printer and said colorants comprise cyan, magenta, yellow and black colored donor sheets.
Claim 26
Dependent Claim
33 words
The system in claim 23 when appendant to claim 22 wherein the marking engine is a sublimation dye transfer laser printer and said colorants comprise cyan, magenta, yellow and black colored donor sheets.
References Cited (Backward Citations)
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