A system and method enable determining a total colorant limit for printing images. The system includes memory which stores instructions for: determining a grain value for each of a set of printed patches printed on a first print media, the grain value being based upon a visual contrast sensitivity function computed for the respective patch, the set of printed patches including patches printed on the print media at different total colorant values; determining a total colorant limit for the first print media, as a function of the total colorant values and corresponding grain values for the printed patches in the set, wherein the total colorant limit is a total colorant value which corresponds to a grain value which does not exceed a threshold grain value for the first print media. A processor executes the instructions.

A colour processor for mapping an image from source to destination colour gamuts includes an input for receiving a source image having a plurality of source colour points expressed according to the source gamut; a colour characterizer configured to, for each source colour point in the source image, determine a position of intersection of a curve with the boundary of the destination gamut; and a gamut mapper configured to, for each source colour point in the source image: if the source colour point lies inside the destination gamut, apply a first translation factor to translate the source colour point to a destination colour point within a first range of values; or if the source colour point lies outside the destination gamut, apply a second translation factor, different than the first translation factor, to translate the source colour point to a destination colour point within a second range of values.

The present principles relate to a method and device for gamut mapping from a first color gamut towards a second color gamut. The method comprises obtaining a preserved key color (prsv_color.sub.K0) and a hue alignment angle (⊖.sub.K0) of the key color (color.sub.K0) for each key color (color.sub.K0) of at least 3 key colors to define a preserved gamut and a rotated gamut; and performing a hue mapping of a current color (color) from the first color gamut towards the second color gamut wherein in case the current color (color) is in a preserved gamut defined by the preserved key color (prsv_color.sub.K0), the hue mapped current color is unchanged, and in case the current color is out of the preserved gamut, the hue mapped current color is calculated from the hue alignment angle (⊖.sub.K0) of two adjacent key colors of the current color (rotated gamut) and from the preserved area.

Techniques for interactively determining/visualizing the color content of a source image and how the corresponding image data is mapped to device colors are described herein. For example, the color content of a digital image can be converted between different color spaces to identify gamut limitations of an output device (e.g., a printing assembly), discover color(s) that cannot be accurately reproduced, etc. Color space conversions enable the transformation of the color content of the digital image from device-specific colorants to a device-independent representation (and vice versa). In some embodiments, these transformations are facilitated using lookup tables that are implemented in graphical processing unit-resident memory.

Color conversion information is used for carrying out a color conversion process to generate a converted image data. The color conversion information is configured as follows. Within a range from a predetermined first reference color value to a black input color value on a specific line, the closer to the black input color value a noticed input color value is, the larger a first output component value becomes. Within a first dark range, the closer to the black input color value the noticed input color value is, the smaller a second output component value becomes. Within a first light range, the closer to the black input color value the noticed input color value is, the larger the second output component value becomes. Within a first intermediate range, the second output component value is constant.

The present principles relate to a method and device for gamut mapping from a first color gamut towards a second color gamut. The method comprises, in a plane of constant hue, mapping the chroma of the color from the first color gamut towards the second color gamut at constant lightness. The chroma mapping further comprises obtaining a target color on the second color gamut boundary wherein the lightness of the target color is greater than or equal to the lightness of a color of maximum chroma of the first color gamut and wherein the lightness of the target color is lower than the lightness of a color of maximum chroma of the second color gamut. In case where the lightness of the color is greater than the lightness of the target color, the chroma mapping comprises mapping at constant lightness the chroma of a color on the first color gamut boundary by a decreasing function of chroma applied to lightness, wherein the respective outputs of the decreasing function applied to the lightness of the target color and to the lightness of the white are the chroma of the target color and the chroma of the white.

Disclosed herein is a method, in particular for interpolating and smoothening the gamut boundary of an image processing device. Color data are received. An initial surface corresponding to the color data in a color space is created and divided into first patches. A first one of the first patches is divided into second patches based on a topology of a second one of the first patches. Further disclosed are a corresponding machine-readable medium and a corresponding system comprising a storage device and a computing device.

Color conversion information is used for carrying out a color conversion process to generate a converted image data. The color conversion information is configured as follows. Within a range from a predetermined first reference color value to a black input color value on a specific line, the closer to the black input color value a noticed input color value is, the larger a first output component value becomes. Within a first dark range, the closer to the black input color value the noticed input color value is, the smaller a second output component value becomes. Within a first light range, the closer to the black input color value the noticed input color value is, the larger the second output component value becomes. Within a first intermediate range, the second output component value is constant.

An information processing apparatus includes circuitry configured to: receive designation of a particular color; obtain device values of a plurality of colors that are present within a predetermined distance or less from the designated particular color in a color space; and determine a patch configuration based on the device values. In determination the patch configuration, the circuitry is configured to determine a gradation change width of each color material based on a degree of change of a device value of each color material.

An embodiment may involve obtaining a three-dimensional color model containing hue, lightness, and chroma dimensions. The color model may represent each of at least one thousand distinct colors as unique points within the hue, lightness, and chroma dimensions. The embodiment may involve displaying, in accordance with the color model, a rotatable three-dimensional representation of the unique points. The embodiment may further involve receiving a selection of a first point of the unique points and a selection of a second point of the unique points. The embodiment may involve, in response to receiving the selection of the first point and the selection of the second point, displaying, in accordance with the color model, a rotatable three-dimensional representation of the first point, the second point, a line connecting the first point and the second point, and a subset of the unique points that are within a particular radius of the line.