Abstract: A method of color halftone processing is disclosed. A plurality of color mappings each provide a mapping from a color value in a color space to a set of Neugebauer Primary area coverage (NPac) values in an NPac space. An imaging metric is obtained for each NPac value in the set. An NPac value in the set is selected based on the imaging metric. The selected NPac value is used as an output NPac value in a combined color mapping for the color value.

Abstract: A method of generating a diagnostic plot for a printing system includes printing a first half of a diagnostic pattern representative of a first state of the printing system, and printing a second half of the diagnostic pattern representative of a second state of the printing system. Variation of the diagnostic pattern from an adjacent diagnostic pattern indicates the printing system is out of specification.

Abstract: A method for color mapping is disclosed. A color mapping is generated based on an imaging model and a color model for an imaging device. The imaging model allows a set of perturbations to be modelled. A set of metamers is determined for one or more colors. For each metamer, at least the imaging model is used to estimate a color output with at least one modelled perturbation. The color outputs are used to select a metamer from the set to be used for the color mapping.

Abstract: A method and system of controlling at least one printbar in a printing system are described. The printing system has one or more of printbars (160, 190) distributed along a media transport. A first image including a reference pattern (240A, 240B) is generated on a print medium (150) with a first printbar (160). A detector (180) then detects a pattern on the print medium. The reference pattern and the detected pattern are used to determine a position of the first image relative to a second printbar (190). This position is used to configure nozzle data for a second image to be generated on the print medium by the second printbar.

Abstract: A method of defining color separation for printing an image via NPacs, the method comprising: selecting a plurality of NPacs corresponding to a plurality of points within an RGB cube to provide a tessellation in RGB space translated to a valid tessellation in an NPac-related space; and defining color separation from the selected NPacs.

Abstract: A calibration target is disclosed. The calibration target is created such that a color patch is sensitive to drop weight changes based on drop weight variations that show greater changes in color for a given change in drop weight.

Abstract: Methods for configuring and calibrating a printing system are described. Configuring a printing system involves obtaining data for determining a reference print element in the printing system. The reference print element is then used to determine calibration data for a given print element. The calibration data is applied for the given print element to generate a print output.

Abstract: A method of color halftone processing is disclosed. A plurality of color mappings each provide a mapping from a color value in a color space to a set of Neugebauer Primary area coverage (NPac) values in an NPac space. An imaging metric is obtained for each NPac value in the set. An NPac value in the set is selected based on the imaging metric. The selected NPac value is used as an output NPac value in a combined color mapping for the color value.

Abstract: In a method to generate a print specification color separation look-up table, a device color space is sampled to provide at least one sampled value. The sampled value is transformed to a device independent color space. The transformed sampled value is gamut mapped using a source color gamut and a color separation color gamut to provide a color separation value. The gamut mapping is performed in an expansion mode and a compression mode.

Abstract: Certain methods of generating a color mapping are described. In one method, an output of a color halftone processing pipeline is processed so as to determine a set of Neugebauer Primary area coverage (NPac) values that are representative of the output of the color halftone processing pipeline. These NPac values are then used, together with knowledge of an original input image, to generating the color mapping.

Abstract: A method for color mapping is disclosed. A color mapping is generated based on an imaging model and a color model for an imaging device. The imaging model allows a set of perturbations to be modelled. A set of metamers is determined for one or more colors. For each metamer, at least the imaging model is used to estimate a color output with at least one modelled perturbation. The color outputs are used to select a Metamer from the set to be used for the color mapping.

Abstract: A calibration target is disclosed. The calibration target is created such that a color patch is sensitive to drop weight changes based on drop weight variations that show greater changes in color for a given change in drop weight.

Abstract: A calibration target is disclosed. The calibration target is created such that a color patch is sensitive to drop weight changes.

Abstract: An example method of transforming colors for a printing device in accordance with the present disclosure is provided. The color printing device comprises a plurality of printing element, each printing element having an element gamut, represented in 3-D space associated therewith. The method comprises defining a first gamut volume in a 3-D space for the printing device, and transforming the defined first gamut volume into the element gamut to create a second gamut volume in 3-D space for the printing device.

Abstract: A method for printing with a printhead, comprising: generating a first imaging matrix comprising cells each containing information related to the ink to be deposited on a corresponding area of the print medium; on the basis of said first matrix, generating a second imaging matrix, comprising cells each containing information related to the ink drops to be deposited on a corresponding area of the print medium; wherein some cells of the second matrix are prioritized and for some of them the information related to the ink drops depends on a cell of the first matrix that corresponds to a different area of the print medium than the area of said prioritized cell of the second matrix; such that upon printing, nozzles of the printhead associated with some prioritized cells fire ink that in the first matrix is associated with areas of the print medium corresponding to non-prioritized cells.

Abstract: A method for printing, comprising: obtaining an imaging matrix, in which each row or each column of cells is associated with at least a nozzle of a printhead, and in which each cell contains an initial value of a parameter which is related to an amount of ink to be deposited on the print medium; dividing the imaging matrix into at least two subsets of cells, such that each cell of the matrix belongs to one of said subsets; associating with each subset of cells a conversion function; obtaining a converted imaging matrix by applying to the initial value in each cell the function that corresponds to the subset to which the cell belongs; and printing using said converted imaging matrix.

Abstract: An apparatus and method for use in generating calibration parameters for an inkjet nozzle are disclosed. The method comprises obtaining data defining how calibration parameters associated with a nozzle change as the number of ink drops ejected from a nozzle increases, determining a number of ink drops ejected from the nozzle, and adjusting calibration parameters for the nozzle based on the determined number of ink drops ejected from the nozzle and the obtained data defining how calibration parameters associated with a nozzle change as the number of ink drops ejected from a nozzle increases.

Abstract: A calibration target is disclosed. The calibration target is created such that a color patch is sensitive to drop weight changes.

Abstract: A method of defining color separation for printing an image via NPacs, the method comprising: selecting a plurality of NPacs corresponding to a plurality of points within an RGB cube to provide a tessellation in RGB space translated to a valid tessellation in an NPac-related space; and defining color separation from the selected NPacs.

Abstract: In a method to generate a print specification color separation look-up table, a device color space is sampled to provide at least one sampled value. The sampled value is transformed to a device independent color space. The transformed sampled value is gamut mapped using a source color gamut and a color separation color gamut to provide a color separation value. The gamut mapping is performed in an expansion mode and a compression mode.