The invention provides a colour standard, assembled from a graphic digital input file, in which one or a combination of CMYK, RGB, Lab or spot colour builds are contained. The colour standard comprises a colour target calibration strip which is indicative of the calibration status of a printing press; an output image which is indicative of the digital input file; and a grid chart of spot colour builds, built-in process inks, with their respective process build values available for each spot colour in the digital input file. The colour standard is configured to capture the calibrated state of the press for a particular digital input file in order to achieve a particular colour-managed output image, so that product print runs of the output image can be repeated accurately and consistently over time.

Embodiments of the present invention disclose a method, computer program product, and system for cataloging images based on a gridded color histogram analysis. The computer accesses an image gallery specified by a user, wherein the image gallery is at least one of an image gallery stored on a user computing device, an image gallery stored on a user account at a third-party image storage, or an image gallery searched on the web. The computer receives a request to search the image gallery specified by the user. The computer performs a search of the image gallery, wherein the search is using a color based histogram algorithm based on a user input. The computer transmits a cataloged and sorted image gallery to the user computing device to be displayed.

A image forming apparatus includes a display, a user input device, a printer unit, and a processor. The processor causes a color patch image output screen to be displayed. The color patch image output screen includes user selectable hues. Once the hue selection is received a color patch image based on the hue selection is displayed. The color patch image includes several different colors indexed by a color number value. A color patch number input screen is then displayed and includes a color to be adjusted input field and a target color input field. User inputs for a first color patch number and a second color patch number are received via the displayed screen. The processor then performs a color conversion such that the first color patch number corresponds to the second color patch number when the printer unit prints an image using the image data.

A method is disclosed wherein data representative of a plurality of colors defined in a color space is received, the plurality of colors providing a color palette taken to be related to each other by predefined color harmony rules based on their relative positions in the color space. An irreproducible color of the color palette outside a rendering system's reproducible color gamut is determined, the reproducible color gamut having been received for a rendering system on which image data comprising colors of the color palette is to be reproduced. A suggested color for a replacement color palette also complying with the predefined color harmony rules is determined based on the reproducible color gamut to bring the color palette towards being within the rendering system's reproducible color gamut.

The invention provides a colour standard, assembled from a graphic digital input file, in which one or a combination of CMYK, RGB, Lab or spot colour builds are contained. The colour standard comprises a colour target calibration strip which is indicative of the calibration status of a printing press; an output image which is indicative of the digital input file; and a grid chart of spot colour builds, built-in process inks, with their respective process build values available for each spot colour in the digital input file. The colour standard is configured to capture the calibrated state of the press for a particular digital input file in order to achieve a particular colour-managed output image, so that product print runs of the output image can be repeated accurately and consistently over time.

Provided is an image processing apparatus including a generating unit configured to print data to be used in a process of printing a metallic image using a metallic ink containing silver particles in an inkjet printing apparatus capable of ejecting the metallic ink and at least one type of chromatic color ink; and an obtaining unit configured to obtain metallic image data corresponding to a predetermined region on a print medium and indicating a tone in the metallic image. The generation unit generates print data of the metallic ink to be printed in the predetermined region based on the metallic image data and generates print data of the chromatic color ink to be printed in the predetermined region based on the metallic image data obtained by the obtaining unit and pre-stored data indicating the correspondences between tone values of the metallic image data and amounts of the chromatic color ink.

Methods, systems and computer readable media for color management are described. In some implementations, the method can include accessing one or more buildup curves associated with a combination of a substrate, one or more colorants and a colorant dispenser. The method can also include accessing a design file specifying a design and including one or more layer files each specifying a layer color. The method can further include generating, for each layer color, a corresponding colorization recipe based on the one or more buildup curves. The method can also include creating a production job instruction/metadata file having a link to the design instruction/metadata file and including parameters associated with the colorant dispensing job to be carried out using the design instruction/metadata file.

A method for generating device-dependent color values which satisfy a colorant limit for an output device includes, for an input color defined by input values for three color channels in a first device-dependent color space, converting the input values to a hue angle , a saturation S, and value V in a second device-dependent color space. Minimum, maximum and middle ones of the input values are identified. The minimum is set to zero and the middle adjusted to maintain the input hue angle. A hue leaf relating output colorant mixture to input color can be constructed for the hue angle, and partitioned into regions. The region of the hue leaf containing the input color is identified and interpolated to identify intermediate values for the input color in a third device-dependent color space, such as CMYK. Output values in the third device-dependent color are the intermediate values or values derived therefrom.

An object of the present invention is to provide an image processing apparatus capable of reducing color material consumption to the maximum while maintaining the hue of an image before and after color conversion to reduce the color material consumption. The present invention is an image processing apparatus having a first lookup table to convert pixel values in a color space into pixel values of color materials, the apparatus including: an acceptable color difference derivation unit configured to derive an acceptable color difference indicating a size of a range of acceptable color difference, which corresponds to each grid point in the color space; a pixel value determination unit configured to determine pixel values of color materials, which corresponds to each of the grid points, based on the derived acceptable color difference; and a lookup table creation unit configured to create a second lookup table to convert pixel values in the color space into the determined pixel values of color materials.

An example method of setting ink limits for a printing system is described. The method involves printing a first set of color ramps. Each color ramp has test areas which are printed based different Neugebauer Primary Area Coverage (NPac) vectors. A test area for each color ramp is indicated that meets an image quality metric and Neugebauer Primary ink use limits are set based on these test areas. A second set of color ramps, for combinations of the set of available Neugebauer Primaries, is then printed, The test areas for each ramp are defined by monotonically-varying vector element values for one Neugebauer Primary in a combination and the second set of ramps are defined by monotonically-varying vector element values across said ramps for another Neugebauer Primary in the combination. Test areas are then indicated again for the second set of color ramps to set ink use limits for the printing system.