Printer driver having gamut-mapped colors

Claim 1

A color printer driver for a printer, comprising: a reproduction look-up table (LUT) which, for each of plural colors both in-gamut and out-of-gamut of the printer, stores color component values for printing by the printer; and means, responsive to a command to print a color, for outputting color component values stored in said reproduction LUT in correspondence to the commanded color; wherein for close-in out-of-gamut colors, said reproduction LUT stores perceptually matched color component values, for far-out-of-gamut colors, said reproduction LUT stores saturation matched color component values, and for intermediate out-of-gamut colors, said reproduction LUT stores color component values corresponding to a smooth blending of perceptually matched color component values and saturation matched color component values.

Claim 7

An apparatus for color printing comprising: a color printer for printing color images in response to color component values, said color printer having a gamut of printable colors; a color monitor for displaying colors within a gamut of displayable colors; a processing unit including a computer for executing stored program process steps, said processing unit including a color monitor interface for providing color primary values to said color monitor and a color printer interface for providing color component values to said color printer; and a memory for storing process steps for execution by said processing unit; said process steps including (a) steps which together comprise an application program for deriving a color image and for displaying and printing the derived color image, (b) steps which together comprise a monitor driver for providing color primary values to said color monitor interface in response to display of the color image by said application program, and (c) steps which together comprise a color printer driver for providing color component values to said color printer interface in response to printing by said application program, wherein for in-gamut colors colorimetrically matched color component values are provided, for close-in-out-of-gamut colors perceptually matched color component values are provided, for far-out-of-gamut colors saturation matched color component values are provided, and for intermediate out-of-gamut colors color component values corresponding to a smooth blending of perceptually matched color component values and saturation matched color component values are provided.

Claim 8

An apparatus for color printing comprising: a color printer for printing color images in response to color component values, said color printer having a gamut of printable colors; a color monitor for displaying colors within a gamut of displayable colors; a processing unit including a computer for executing stored program process steps, said processing unit including a color monitor interface for providing color primary values to said color monitor and a color printer interface for providing color component values to said color printer; and a memory for storing process steps for execution by said processing unit; said process steps including (a) steps which together comprise an application program for deriving a color image and for displaying and printing the derived color image, (b) steps which together comprise a monitor driver for providing color primary values to said color monitor interface in response to display of the color image by said application program, and (c) steps which together comprise a color printer driver for providing color component values to said color printer interface in response to printing by said application program, wherein for in-gamut colors colorimetrically matched color component values are provided, for close-in-out-of-gamut colors perceptually matched color component values are provided, for far-out-of-gamut colors saturation matched color component values are provided, and for intermediate out-of-gamut colors color component values corresponding to a smooth blending of perceptually matched color component values and saturation matched color component values are provided.

Claim 21

An apparatus for color printing comprising: a color printer for printing color images in response to color component values, said color printer having a gamut of printable colors; a color monitor for displaying colors within a gamut of displayable colors; a processing unit including a computer for executing stored program process steps, said processing unit including a color monitor interface for providing color primary values to said color monitor and a color printer interface for providing color component values to said color printer; a memory for storing process steps for execution by said processing unit; said process steps including (a) steps which together comprise an application program for deriving a color image and for displaying and printing the derived color image, (b) steps which together comprise a monitor driver for providing color primary values to said color monitor interface in response to display of the color image by said application program, and (c) steps which together comprise a color printer driver for providing color component values to said color printer interface in response to printing by said application program, said color printer driver including a reproduction look-up table (LUT) which, for each of plural colors both in-gamut and out-of-gamut of the printer, stores color component values for printing by said printer, wherein for out-of-gamut colors said reproduction LUT stores color component values obtained by dual-cone gamut mapping in which an actual cone of N-cone arranged surfaces is defined which mimics the actual gamut of the printer, in which an ideal cone of M-cone arranged surfaces is defined which mimics the gamut of the color monitor, in which a target out-of-gamut color is projected onto the actual cone and de-saturated until in-gamut color component values are obtained, in which the same target color is projected onto the ideal cone to obtain fully-saturated color component values, and in which a weighted average is obtained of the in-gamut color component values and the fully-saturated color component values, weight being based on a measure of distance between the out-of-gamut target color and its projection onto the actual cone.

Claim 22

An apparatus for color printing comprising: a color printer for printing color images in response to color component values, said color printer having a gamut of printable colors; a color monitor for displaying colors within a gamut of displayable colors; a processing unit including a computer for executing stored program process steps, said processing unit including a color monitor interface for providing color primary values to said color monitor and a color printer interface for providing color component values to said color printer; a memory for storing process steps for execution by said processing unit; said process steps including (a) steps which together comprise an application program for deriving a color image and for displaying and printing the derived color image, (b) steps which together comprise a monitor driver for providing color primary values to said color monitor interface in response to display of the color image by said application program, and (c) steps which together comprise a color printer driver for providing color component values to said color printer interface in response to printing by said application program, said color printer driver including a reproduction look-up table (LUT) which, for each of plural colors both in-gamut and out-of-gamut of the printer, stores color component values for printing by said printer, wherein for out-of-gamut colors said reproduction LUT stores color component values obtained by dual-cone gamut mapping in which an actual cone of N-cone arranged surfaces is defined which mimics the actual gamut of the printer, in which an ideal cone of M-cone arranged surfaces is defined which mimics the gamut of the color monitor, in which a target out-of-gamut color is projected onto the actual cone and de-saturated until in-gamut color component values are obtained, in which the same target color is projected onto the ideal cone to obtain fully-saturated color component values, and in which a weighted average is obtained of the in-gamut color component values and the fully-saturated color component values, weight being based on a measure of distance between the out-of-gamut target color and its projection onto the actual cone.

Claim 29

A method for storing color component values into a reproduction look-up table (LUT), the color component values for printing by a color printer in response to commands to print both in-gamut and out-of-gamut colors, the method comprising the steps of: measuring colors printed by the printer in response to a suitably large number of various combinations of the color component values; constructing a forward mapping which maps color component values into printed colors; opening a blank reproduction LUT which, for each of plural different input colors both in-gamut and out-of-gamut, will map the input color to a printable color component value; testing whether each color in the blank reproduction LUT is in-gamut or out-of-gamut; for in-gamut colors storing in the blank-reproduction LUT a color component value derived from the forward mapping; for out-of-gamut colors applying a dual-cone gamut mapping so as to obtain a gamut-mapped color component value, and storing the gamut-mapped color component value into the blank reproduction LUT; and smoothing the reproduction LUT.

Claim 30

A method for storing color component values into a reproduction look-up table (LUT), the color component values for printing by a color printer in response to commands to print both in-gamut and out-of-gamut colors, the method comprising the steps of: measuring colors printed by the printer in response to a suitably large number of various combinations of the color component values; constructing a forward mapping which maps color component values into printed colors; opening a blank reproduction LUT which, for each of plural different input colors both in-gamut and out-of-gamut, will map the input color to a printable color component value; testing whether each color in the blank reproduction LUT is in-gamut or out-of-gamut; for in-gamut colors storing in the blank-reproduction LUT a color component value derived from the forward mapping; for out-of-gamut colors applying a dual-cone gamut mapping so as to obtain a gamut-mapped color component value, and storing the gamut-mapped color component value into the blank reproduction LUT; and smoothing the reproduction LUT.