An image processing is configured to convert a color of a first object into gray having first brightness and a color of a second object into gray having second brightness lower than the first brightness by a fixed value in response to receiving color data including the first object and the second object, and output gray data based on the first brightness of gray into which the color of the first object is converted and the second brightness of gray into which the color of the second object is converted.

In an example, a method includes obtaining, by a processor, a first set of vertices of a set of simplexes defining a hull of an initial color gamut. A value representing a size of a first simplex of the set of simplexes may be determined and compared to a first threshold. When the determined value is less than the first threshold, at least one vertex of the first simplex may be removed from the first set of vertices to determine a modified color gamut hull.

A recording device includes a recording unit configured to execute recording on a recording medium using a color material of cyan, magenta, yellow, and black, and a control unit configured to control recording executed by the recording unit, wherein the control unit causes the recording unit to record an edge region of black data included in image data using at least the color material of black, causes the recording unit to record an inner region on an inner side of the edge region of the black data using at least the color material of cyan, magenta, and yellow, and sets the amount of the color material of black per unit area of the edge region to be greater than the amount of the color material of black per unit area of the inner region.

An embodiment of the present disclosure provides a method for processing an image. The method comprise: determining weights corresponding to candidate colors for a target color based on an original color of a pixel in the image; selecting a target color of the pixel from the candidate colors based on the weights; and converting the original color of the pixel into the target color to obtain a target image. According to the embodiment of the present disclosure, by determining the weights of the candidate colors, the image can be converted into the target image comprising only the candidate colors, thereby using a limited number of candidate colors to represent the target image.

An embodiment of the present disclosure provides a method for processing an image. The method comprise: determining weights corresponding to candidate colors for a target color based on an original color of a pixel in the image; selecting a target color of the pixel from the candidate colors based on the weights; and converting the original color of the pixel into the target color to obtain a target image. According to the embodiment of the present disclosure, by determining the weights of the candidate colors, the image can be converted into the target image comprising only the candidate colors, thereby using a limited number of candidate colors to represent the target image.

An image processing apparatus includes processing circuitry. The processing circuitry is configured to compose background information with latent image information to generate a latent-image-embedded image, add the latent-image-embedded image to print data, and at least one of extract the latent image information from the print data and extract the background information from the print data.

A method for calibrating and converting colors of a digital image into printer specific colorant control values is disclosed. This method comprises the steps of calibrating a specific printer of a printer type according to a printer type specific procedure, wherein for each colorant separately a one-dimensional relationship between a printer tone value and a colorant control value is established; profiling the printer type to establish an output profile that defines a relationship between color values in a profile connecting color space and the printer tone values; deriving from the input profile and the output profile a one-dimensional relationship between a black channel and the black printer tone value of the printer; determining if an image color value is to be converted either by using the profiles or by using the one-dimensional relation; converting the image color value and subsequently using the printer calibration relations to obtain the colorant control values. This procedure enables the use of G7 colors in a printer that is limited in its amount of colorant that can be applied locally.

An image processing apparatus includes: an acquisition unit configured to acquire a plurality of first color values in a device independent color space, from information defining a predetermined gamut; a setting unit configured to set predetermined first dot percentages of a fluorescent color for the plurality of first color values acquired by the acquisition unit; a calculation unit configured to calculate a second dot percentage of the fluorescent color, based on a relationship between the plurality of first color values and the first dot percentages, the second dot percentage corresponding to an arbitrary second color value in the color space; and a generation unit configured to generate a first profile to convert the second color value to dot percentages of a process color and the fluorescent color, based on the second color value and the second dot percentage calculated by the calculation unit.

An information processing apparatus includes circuitry to derive, referring to a dictionary in which a target color having brightness and gloss is associated with a combination of amounts of color materials including one or more process color materials and a color material having brightness and gloss, amounts of the one or more process color materials and another amount of another color material, such that an amount corresponding to at least a part of the one or more process color materials corresponding to the target color in the dictionary is replaced with the another amount of the another color material. The combination of the amounts of color materials is for reproducing the target color included in an image formed by an image forming apparatus. The circuitry further updates the dictionary with the amounts of the one or more process color materials and the another amount of the another color material.

An image processing apparatus includes a processor configured to: store a first color patch used in using metallic toner and a second color patch used in using CMYK toner other than the metallic toner without using the metallic toner; receive a first colorimetric value obtained by measuring color of the first color patch and a second colorimetric value obtained by measuring color of the second color patch; calculate a third colorimetric value on a basis of the first colorimetric value obtained by measuring the color of the first color patch and the second colorimetric value obtained by measuring the color of the second color patch, and generate a profile to be used to convert an input color value into an output color value, the profile being generated on a basis of the third colorimetric value; and calculate the third colorimetric value that ranges from the first colorimetric value to the second colorimetric value in response to a total amount of CMYK toner being lower than or equal to a threshold, the total amount of the CMYK toner resulting from color conversion of the input color value performed by using the profile, and calculate the third colorimetric value that coincides with the first colorimetric value in response to the total amount exceeding the threshold.