US 5,309,246 A · Technique for generating additional colors in a halftone color image through use of overlaid primary colored halftone dots of varying size

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.

Claims49

Dependent claims

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 contone input image, the method comprising the steps of:

obtaining data representing a plurality of color 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 a halftone dot for each one of the incoming contone values in each of said separations having a selected size and solid area density wherein the size and solid area density of said halftone dot is related to said each one of the incoming contone values so as to form a plurality of component halftone dots;
printing spatially corresponding component halftone dots from each of said separations each with a corresponding one of said colorants in superposition in a selected order and in registration so as to form composite halftone dots which collectively depict said desired color

A method for generating a desired color in a halftone proof image from a plurality of different colorants in a direct digital color proofing system for generating the color halftone proof image from in-coming digitized prepress contone data for an input image, said system having means for processing the incoming prepress contone data to yield screened color halftone separation data representing halftone separations that are to collectively form the proof image, and a marking engine for writing each of said halftone separations with proper registration so as to form said proof image, comprising the steps of:

in said processing means:
obtaining data representing a plurality of color 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;
and
generating a halftone dot for each one of the incoming contone values in each of said separations having a selected size and solid area density wherein the size and solid area density of said halftone dot is related to said each one of the incoming contone values so as to form a plurality of component halftone dots;
and
in said marking engine:
printing spatially corresponding component halftone dots from each of said separations each with a corresponding one of said colorants in superposition in a selected order and in registration so as to form composite halftone dots which collectively depict said desired color.

4 more elements

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 contone input image, the apparatus comprising:

means for obtaining data representing a plurality of color 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 a halftone dot for each one of the incoming contone values in each of said separations having a selected size and solid area density wherein the size and solid area density of said halftone dot is related to said each one of the incoming contone values so as to form a plurality of component halftone dots;
means for printing spatially corresponding component halftone dots from each of said separations each with a corresponding one of said colorants in superposition in a selected order and in registration so as to form composite halftone dots which collectively depict said desired color.

A direct digital color proofing system for generating a color halftone proof image from incoming digitized prepress contone data for an input image, said system having means for processing the incoming pre-press contone data to yield screened color halftone separation data representing halftone separations that are to collectively form the proof image, and a marking engine for writing each of said halftone separations with proper registration so as to form said proof image, wherein said system generates a desired color in the halftone proof image from a plurality of different colorants, said system comprising:

in said processing means:
means for obtaining data representing a plurality of color 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;
and
means for generating a halftone dot for each one of the incoming contone values in each of said separations having a selected size and solid are density wherein the size and solid area density of said halftone dot is related to said each one of the incoming contone values so as to form a plurality of component halftone dots;
and
in said marking engine:
means for printing spatially corresponding component halftone dots from each of said separations each with a corresponding one of said colorants in superposition in a selected order and in registration so as to form composite halftone dots which collectively depict said desired color.

4 more elements

Dependencies are inferred from the claim text.

Technique for generating additional colors in a halftone color image through use of overlaid primary colored halftone dots of varying size

Life of this patent

Technique for generating additional colors in a halftone color image through use of overlaid primary colored halftone dots of varying size

Life of this patent

Abstract

Claims49