Abstract: In an example, a method comprises: receiving, at a raster image processor, image data representing a print job, the image data representing an area to be printed using a process color separation and an area to be printed using a spot color; producing at the raster image processor, a first rasterized image representing a layer of the print job having the process color and a second rasterized image representing a layer of the print job having the spot color; receiving at an emulator, the second rasterized image; and representing, by the emulator, the second rasterized image as a plurality of constituent process color separation layers.

Abstract: In an example of the disclosure, a device (38) includes: an acquiring unit to obtain first reflectance output values acquired from reference samples (52) by a reference color measuring device and to obtain second reflectance output values acquired from the reference samples (52) by a second color measuring device (2); a processing unit to determine, for a plurality of wavelength values, correspondences between a first reflectance output value acquired by the reference color measuring device and a second reflectance output value acquired by the second color measuring device, and to perform, for each wavelength value, an interpolation based on the correspondences to obtain interpolation data; and a correcting unit to correct, based on the interpolation data, third reflectance output values acquired by the second color measuring device (2) from a sample of interest (12).

Abstract: An example of printing calibration includes printing a calibration page having test patches, the test patches developed at a plurality of voltages of a binary ink developer. The test patches are measured to determine an indication of ink thickness of the patches and a calibration voltage is generated based on the indications of the ink thickness of the test patches.

Abstract: In an example of the disclosure, a device (38) includes: an acquiring unit to obtain first reflectance output values acquired from reference samples (52) by a reference color measuring device and to obtain second reflectance output values acquired from the reference samples (52) by a second color measuring device (2); a processing unit to determine, for a plurality of wavelength values, correspondences between a first reflectance output value acquired by the reference color measuring device and a second reflectance output value acquired by the second color measuring device, and to perform, for each wavelength value, an interpolation based on the correspondences to obtain interpolation data; and a correcting unit to correct, based on the interpolation data, third reflectance output values acquired by the second color measuring device (2) from a sample of interest (12).

Abstract: A method is provided. The method comprises receiving a signal representative of a first combined spectrophotometric response of a substrate and deposited colorant. The first combined spectrophotometric response is indicative of a combined reflectance of the substrate and deposited colorant under a first illumination condition. The method further comprises determining, from the received signal, and from a contribution term indicative of an effect of ultra-violet, UV, light on a combined reflectance of the substrate and deposited colorant, an estimate for a second combined spectrophotometric response of the substrate and deposited colorant under a second illumination condition. The first illumination condition or the second illumination condition is a UV-cut illumination condition.

Abstract: A method of printing comprises executing an output settings calibration procedure, the procedure comprising: depositing, by one or more printing elements, ink onto a first substrate according to respective output settings. The procedure further comprises measuring, by a sensor, an actual color value of the ink deposited onto the first substrate at each of a plurality of locations. The procedure further comprises determining a difference between the actual color value and a target color value for each of the plurality of locations and determining adjusted respective output settings for each of the plurality of locations based on the determined difference. The method further comprises depositing, by the one or more printing elements, ink onto a second substrate according to the adjusted respective output settings.

Abstract: A method of printing comprises executing an output settings calibration procedure, the procedure comprising: depositing, by one or more printing elements, ink onto a first substrate according to respective output settings. The procedure further comprises measuring, by a sensor, an actual color value of the ink deposited onto the first substrate at plurality of locations. The procedure further comprises determining a difference between the actual color value and a target color value for each of the plurality of locations and determining adjusted respective output settings for each of the plurality of locations based on the determined difference. The method further comprises depositing, by the one or more printing elements, ink onto a second substrate according to the adjusted respective output settings.

Abstract: Measures for use in calibrating a printing device. Historical dot gain linearization lookup table data for the printing device is processed. On the basis of the processed historical dot gain linearization lookup table data, a plurality of input points for a current dot gain linearization lookup table are dynamically determined. The printing device is calibrated according to the dynamically determined current dot gain linearization lookup table.

Abstract: A method of adjusting an imaging apparatus comprises printing a set of test patches, the set of test patches comprising a solid color patch, a grey level patch and a substrate patch. The optical densities of the set of test patches are determined. The method comprises simultaneously correcting a solid optical density value (Solid OD), relating to the solid color patch and an associated grey level (LUT) value relating to the grey level patch.

Abstract: Printing with a first print engine on a front side of a substrate, and a second print engine on the rear side of the substrate, wherein a first spectrophotometer sensor and a second spectrophotometer sensor are used for spectrophotometric measurements on the blank front and rear sides of the substrate, and producing correction data which represent a deviation of the spectrum representing output signals from the first and second sensors, and wherein a correction derived from the correction data compensates a deviation in the spectral reflectivity of at least one of the front side and the rear side of the substrate. Cross-calibrating the first and second sensors is by processing the spectrum representing output signals of the sensors from identical spectrophotometric measurements.

Abstract: Measures for use in calibrating a printing device. Historical dot gain linearization lookup table data for the printing device is processed. On the basis of the processed historical dot gain linearization lookup table data, a plurality of input points for a current dot gain linearization lookup table are dynamically determined. The printing device is calibrated according to the dynamically determined current dot gain linearization lookup table.

Abstract: A method of adjusting an imaging apparatus comprises printing a set of test patches, the set of test patches comprising a solid color patch, a grey level patch and a substrate patch. The optical densities of the set of test patches are determined. The method comprises simultaneously correcting a solid optical density value (Solid OD), relating to the solid color patch and an associated grey level (LUT) value relating to the grey level patch.

Abstract: A spectrophotometer diagnosis system and a method for diagnosing a spectrophotometer, wherein at least one test patch is printed in proximity to at least one non-printed substrate patch, at least one value characteristic of the at least one test patch and/or the at least one substrate patch is measured using the spectrophotometer, and at least one diagnostic score for the spectrophotometer is determined based on the at least one measured value in comparison with a reference value.

Abstract: A spectrophotometer diagnosis system and a method for diagnosing a spectrophotometer, wherein at least one test patch is printed in proximity to at least one non-printed substrate patch, at least one value characteristic of the at least one test patch and/or the at least one substrate patch is measured using the spectrophotometer, and at least one diagnostic score for the spectrophotometer is determined based on the at least one measured value in comparison with a reference value.

Abstract: In an example implementation, a processor-readable medium stores code representing instructions that when executed by a processor cause a plurality of patches to be printed onto a substrate. Each patch comprises a first colored line and a second colored line that are parallel to one another and separated by a distance X. For each patch, a measured reflection value is received and mapped to a curve as a function of X. A color plane registration value is then estimated by interpolating a maximum reflection value between the two highest measured reflection values on the curve.