An image forming apparatus includes a table generating unit. The table generating unit, in a Voronoi diagram, obtains empty circles as circles centered at Voronoi seeds of ends of Voronoi sides that intersect with a straight line passing through a largest saturation color and a smallest-saturation and specific-lightness color and passes through generatrices. After the table generating unit sets one of the generatrices shared by the two adjacent empty circles whose radius ratio is outside a specific range as a target point, and causes the radius ratio of the two empty circles to be within the specific range by changing at least one radius of the two empty circles, the table generating unit generates the conversion table that sets a color that corresponds to an intersection point corresponding to the target point among the intersection points of the two empty circles, as the definition colors.

An image processing apparatus includes: a display control section that causes a display device to display an image indicating a state in which a figure indicating a color gamut, a dot indicating a designated color, and one or more axes each indicating a feature amount of a color are viewed in an identical three-dimensional color space from a predetermined viewpoint; and a receiving section that receives an instruction issued by a user. The display control section changes, in accordance with the instruction, the image upon changing the viewpoint.

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.

An image processing apparatus for displaying an image on a display screen, inputs data, specifies at least one of a bright region and a dark region of an image corresponding to the image data, executes, for at least one of the bright region and the dark region, at least one of first chroma processing of increasing a chroma of the bright region, second chroma processing of lowering the chroma of the dark region, first hue processing of making a hue of the bright region close to red, and second hue processing of making the hue of the dark region close to blue in accordance with display dynamic range information corresponding to the display screen, and displays, on the display screen, an image based on corrected image data that has undergone correction.

A color processing apparatus includes first, second, and third acquiring units. The first acquiring unit acquires first color data indicating association among first-space color in a first space, second-space color obtained using a reading unit reading measurement images having different first-space colors, and third-space color obtained by converting the second-space color through a predetermined transformation model. The second acquiring unit acquires second color data indicating association between the first-space color and the third-space color obtained using a measuring unit performing color measurement on some of the specific-color measurement images containing a specific color in the first space and included in the measurement images. The third acquiring unit acquires third color data indicating association between the first-space color and the third-space color obtained by converting the first-space color through a transformation equation obtained from the first and second color data. The conversion is performed on the other specific-color measurement images.

In embodiments of color rendering on a hue plane, a color rendering module can receive three channels of color information. The color rendering module converts the three channels of color information to two channels of color information and performs a color rendering operation on the two channels of color information to provide two channels of rendered color information. The color rendering module then converts the two channels of rendered color information back to three channels of rendered color information.

A method of color mapping color values of an oligochromatic pattern comprising the following steps: determining an image-gamut, in a N-dimensional device independent color system (ND-DICS), of said oligochromatic pattern; wherein said image-gamut comprises said color values of said oligochromatic pattern; and determining a skeleton (500) of said image-gamut; and performing an adaption on said skeleton (500) in said ND-DICS by a set of N-dimensional-transforming steps (30) and determining for points of said skeleton (500), a path in said ND-DICS that corresponds to said adaption; and color mapping said color values, of said oligochromatic pattern, based on said determined paths (35) of said points of said skeleton (500).

An automatic document feeding device includes a conveyance unit, an image reading unit, a color reference member, a moving assembly, and a drive source. The drive source includes a rotation output shaft to drive the conveyance unit and the moving assembly. The drive source changes the rotation output shaft from a forward rotation direction to a reverse rotation direction to reversely rotate the rotation output shaft to a set reverse rotation angle set in advance, according to a condition of conveyance of the document. In a rotation transmission route from the rotation output shaft to the moving assembly, the movement regulator is disposed in a first reverse rotation drive region from when a rotation direction of the rotation output shaft is changed to the reverse rotation direction to when a rotation angle of the rotation output shaft after the change in the reverse rotation direction reaches the set reverse rotation angle.

The invention relates to a process for producing a printed image on a substrate comprising the steps of selecting eight or fewer process colors from a known process ink color set; providing two or more spot colors, forming a color set comprising the process colors and the spot colors; and optionally printing the image using the formed color set. The ratio of the number of spot colors to the number of process colors is at least 0.5:1.

An information processing apparatus includes an acquisition unit that acquires a designated color which is designated as a color, which is converted into a specific color, of a pixel among pixels which express an image, a determination unit that determines whether or not a common color area, which is expressed by pixels in a common hue range, expresses prescribed information in the image, and a conversion unit that performs a first conversion process of converting a pixel corresponding to the acquired designated color into a specific color in the common color area which is determined to express the information, and performs a second conversion process of converting a pixel corresponding to a color in a wider hue range than the designated color into a specific color in the common color area which is determined to not express the information.