Abstract: An apparatus and method for use in generating calibration parameters for a printing apparatus comprising a plurality of print modules are disclosed. The method comprises printing a first plurality of test patches for each print module of the plurality of print modules, analysing the first plurality of test patches to identify at least two clusters of print modules, wherein each cluster comprises a sub-group of print modules having substantially similar performance, printing a second plurality of test patches comprising an extended calibration test patch set for each cluster of print modules, the second plurality of test patches being distributed across the print modules of the cluster, and analysing extended calibration test patch set for each cluster to determine a calibration parameter for the printing apparatus.

Abstract: In some examples, a method for compressing a spectral reflectance dataset may be performed through compression circuitry. The method may include computing a principal component analysis basis for the spectral reflectance dataset; projecting the spectral reflectance dataset onto the principal component analysis basis to obtain a weight matrix; quantizing the weight matrix; performing a Huffman encoding process on the quantized weight matrix to generate a Huffman table and Huffman codes for the quantized weight matrix; and providing compressed spectral reflectance data as the principal component analysis basis, the Huffman table, and the Huffman codes.

Abstract: A method is described in which printing instructions representing printing content to be printed by a printing system are received, the printing system comprising a dispenser to dispense printing material. Whether to perform a first mapping process or a second mapping process is then selected. The first mapping process comprises mapping an indicator to a first dispensing process to dispense printing material from the dispenser to produce content according to a content characteristic of the printing content at a given location, and the second mapping process comprises mapping the indicator to a second dispensing process to dispense printing material to produce content according to the content characteristic at the given location. The first dispensing process is different than the second dispensing process. The indicator represents the content characteristic. The method also comprises performing the selected mapping process.

Abstract: A color calibration chart may be created including a plurality of colors that are variations of a print color established for printing a reference color by a printing system using multiple colors. The colors in the calibration chart may be measured. A color from the calibration chart may be selected for printing the reference color which has a measurement value indicative of a color consistency within a predefined distance from a reference value for the print color.

Abstract: An apparatus and method for use in generating calibration parameters for a printing apparatus comprising a plurality of print modules are disclosed. The method comprises printing a first plurality of test patches for each print module of the plurality of print modules, analysing the first plurality of test patches to identify at least two clusters of print modules, wherein each cluster comprises a sub-group of print modules having substantially similar performance, printing a second plurality of test patches comprising an extended calibration test patch set for each cluster of print modules, the second plurality of test patches being distributed across the print modules of the cluster, and analysing extended calibration test patch set for each cluster to determine a calibration parameter for the printing apparatus.

Abstract: In one example of the disclosure, a print job with instructions for printing an image at a resolution is obtained. A display of the image, at the resolution, at a display device is caused. A first reference and a second reference are indicated within the displayed image. A quantity of pixels between the first and second references is determined. An indication of a real distance between the first and second references is received. A desired scale for the image is obtained. A rescale factor for the image is determined based on the resolution, the determined pixel quantity, the real distance, and the desired scale.

Abstract: In some examples, a method for compressing a spectral reflectance dataset may be performed through compression circuitry. The method may include computing a principal component analysis basis for the spectral reflectance dataset; projecting the spectral reflectance dataset onto the principal component analysis basis to obtain a weight matrix; quantizing the weight matrix; performing a Huffman encoding process on the quantized weight matrix to generate a Huffman table and Huffman codes for the quantized weight matrix; and providing compressed spectral reflectance data as the principal component analysis basis, the Huffman table, and the Huffman codes.

Abstract: A color calibration chart may be created including a plurality of colors that are variations of a print color established for printing a reference color by a printing system using multiple colors. The colors in the calibration chart may be measured. A color from the calibration chart may be selected for printing the reference color which has a measurement value indicative of a color consistency within a predefined distance from a reference value for the print color.

Abstract: A computer implemented method of analyzing the content of a digital image, for example a page to be printed, computes a boundary enclosing all the non-white content of the image. The image within the boundary is then divided into regions based on a predetermined division rule. For each region the number of unique colors and the proportion of non-white pixels are computed. The image is then categorized according to the result of those computations. The categorization can be used to automatically set print settings according to the content of the image.

Abstract: A method of preparing the rendering with a color output device of at least one object, the method comprising —computing a first output color profile of a first color model, said profile mimicking, for the human eye, a second output color profile of a second color model, said first output color profile being used in a description of said at least one object in a page description language, and the second output color profile being the output device profile, —and converting colors of pixels of the representation of the at least one object obtained by application of a rendering engine to said description, from the first output color profile to the second output color profile.

Abstract: A color look-up-table (LUT) is created for use by an imaging system which uses a resource to display an image and/or provides an attribute of the image. A method of creating the LUT, comprises selecting a threshold value of resource usage and/or metric of the attribute. A predetermined color look-up-table representing a mapping from color values of a first color gamut to color values displayable by the imaging system is accessed. The predetermined color look-up-table has nodes defining colors to be displayed for the said color values. Resource usage and/or attribute values associated with the said nodes are compared with the threshold value thereby determining the set of nodes of the predetermined gamut having a resource usage and/or attribute values less than the threshold value. A new look-up-table is created which maps the said predetermined color gamut look-up-table to the said set of nodes.

Abstract: Method of setting up a color separation table for a specific print system, comprising finding first NP (Neugebauer Primary) area coverages of a specific print system that correspond to color values, adding second NP area coverages by converting halftone data from at least one pre-determined pair of halftone data and corresponding color value to NP area coverages, and generating a color separation table arranged as input for a halftone process that comprises color values linked to the corresponding first and second NP area coverages.

Abstract: A color look-up-table (LUT) is created for use by an imaging system which uses a resource to display an image and/or provides an attribute of the image. A method of creating the LUT, comprises selecting a threshold value of resource usage and/or metric of the attribute. A predetermined color look-up-table representing a mapping from color values of a first color gamut to color values displayable by the imaging system is accessed. The predetermined color look-up-table has nodes defining colors to be displayed for the said color values. Resource usage and/or attribute values associated with the said nodes are compared with the threshold value thereby determining the set of nodes of the predetermined gamut having a resource usage and/or attribute values less than the threshold value.

Abstract: In one example of the disclosure, a print job with instructions for printing an image at a resolution is obtained. A display of the image, at the resolution, at a display device is caused. A first reference and a second reference are indicated within the displayed image. A quantity of pixels between the first and second references is determined. An indication of a real distance between the first and second references is received. A desired scale for the image is obtained. A rescale factor for the image is determined based on the resolution, the determined pixel quantity, the real distance, and the desired scale.

Abstract: A color look-up-table (LUT) is created for use by an imaging system which uses a resource to display an image and/or provides an attribute of the image. A method of creating the LUT, comprises selecting (S1) a threshold value of resource usage and/or metric of the attribute. A predetermined color look-up-table representing a mapping from color values of a first color gamut to color values displayable by the imaging system is accessed. The predetermined color look-up-table has nodes defining colors to be displayed for the said color values. Resource usage and/or attribute values associated with the said nodes are compared with the threshold value thereby determining the set of nodes of the predetermined gamut having a resource usage and/or attribute values less than the threshold value (S2a, S2b, S3, S4). A new look-up-table is created (S5) which maps the said predetermined color gamut look-up-table to the said set of nodes.

Abstract: A computer implemented method of analysing the content of a digital image, for example a page to be printed, computes a boundary enclosing all the non-white content of the image. The image within the boundary is then divided into regions based on a predetermined division rule. For each region the number of unique colours and the proportion of non-white pixels are computed. The image is then categorised according to the result of those computations. The categorisation can be used to automatically set print settings according to the content of the image.

Abstract: A method of preparing the rendering with a color output device of at least one object, the method comprising—computing a first output color profile of a first color model, said profile mimicking, for the human eye, a second output color profile of a second color model, said first output color profile being used in a description of said at least one object in a page description language, and the second output color profile being the output device profile,—and converting colors of pixels of the representation of the at least one object obtained by application of a rendering engine to said description, from the first output color profile to the second output color profile.

Abstract: A measured distance is received from a distance sensor, where the measured distance is indicative of a distance between a color sensor and a substrate. Using the measured distance, a location of a given projection of projections of a substrate support is determined. A color of a color patch on the substrate at the determined location of the given projection is determined.

Abstract: A color look-up-table (LUT) is created for use by an imaging system which uses a resource to display an image and/or provides an attribute of the image. A method of creating the LUT, comprises selecting (S1) a threshold value of resource usage and/or metric of the attribute. A predetermined color look-up-table representing a mapping from color values of a first color gamut to color values displayable by the imaging system is accessed. The predetermined color look-up-table has nodes defining colors to be displayed for the said color values. Resource usage and/or attribute values associated with the said nodes are compared with the threshold value thereby determining the set of nodes of the predetermined gamut having a resource usage and/or attribute values less than the threshold value (S2a, S2b, S3, S4). A new look-up-table is created (S5) which maps the said predetermined color gamut look-up-table to the said set of nodes.

Abstract: A measured distance is received from a distance sensor, where the measured distance is indicative of a distance between a color sensor and a substrate. Using the measured distance, a location of a given projection of projections of a substrate support is determined. A color of a color patch on the substrate at the determined location of the given projection is determined.