Abstract: In an example, a method includes obtaining, by processing circuitry, a mapping from at least one measured color characteristic of a first substrate to at least one measured color characteristic of a second substrate, wherein the at least one measured color characteristic of the first substrate comprises a measured color characteristic of an unmarked portion of the first substrate and the at least one measured color characteristic of the second substrate comprises a measured color characteristic of an unmarked portion of the second substrate. In some examples the method further includes applying, by processing circuitry, the mapping to a first color which is obtained when applying at least one colorant according to a first colorant specification on the first substrate to determine a predicted color to be obtained by applying at least one colorant according to the first colorant specification on the second substrate.

Abstract: Certain examples described herein relate to halftone level adjustment for Neugebauer Primaries (NPs). In certain examples, halftone levels for NPs are obtained for a halftone for printing an image. It is determined whether the halftone corresponds to a line or an area fill. The halftone levels may be adjusted in response to these levels exceeding a printing attribute threshold. The printing attribute threshold may be dependent on whether the halftone corresponds to a line or an area fill. The image may then be printed using the adjusted halftone levels.

Abstract: Certain examples relate to a method of a method of color prediction in multiple rendering contexts. In one example the method determines a plurality of color prediction models for respective color rendering contexts, each color prediction model mapping between a device dependent color and a rendered color. Measurement data of the rendered color in one said context obtained and mapped to a corrected device color. The corrected device color may be used to predict rendered corrected color for another said context using respective color prediction models.

Abstract: Certain examples relate to a method of a method of printing an image which comprises determining image data for an image to be printed onto a substrate, the image data comprising application amounts of one or more colorants to be applied to the substrate. A print mode is determined for applying the colorants to the substrate and comprises a plurality of application passes each for applying some of the application amounts of the colorants to the substrate and a drying delay between at least some of the application passes. The duration of the drying delay is dependent on a characteristic of one or more of the colorants or substrate. The image is printed using the image data and the print mode.

Abstract: Certain examples relate to a method of printing management. An image is received for printing and printing parameters to print the image are determined. The image is printed onto a substrate using the printing parameters, and the image is printed with an embedded code corresponding to the printing parameters. The printing parameters are associated with the embedded code such that the printing parameters are retrievable from the embedded code.

Abstract: Certain examples described herein relate to the control of colorants and treatments for printing. In certain examples image data, a colorant color mapping and one or more treatment color mappings is obtained. The colorant color mapping may be used to map the image data to colorant application values. The one or more treatment color mappings may be used to map the image data to treatment application values. The colorant application values and treatment application values may be used to generate discrete print control instructions to apply the set of colorants and set of treatments to a printing substrate.

Abstract: Mask entries for each of a plurality of passes over which print fluid drops are to be dispensed for printing an image are generated based on different types of masks and based on image data for the image. Print fluid drop dispensation for a pixel for which the mask entries for a given pass specify repeated print fluid drop dispensation is moved to a mask entry for an adjacent pass that does not specify print fluid drop dispensation for the pixel. Ejection of print fluid to print the image is caused based on the generated mask entries.

Abstract: A system encodes a plurality of colorant vectors of a printer in a Neugebauer Primary area coverage (NPac) vector for use in selecting colorants to output an image by the printer. The encoding includes using a function that relates the plurality of colorant vectors to an NP matrix including a plurality of sets of NPs that correspond to different colorant vectors of the plurality of colorant vectors, and determining the NPac vector based on achieving an objective for the function.

Abstract: Certain examples described herein relate to halftone level adjustment for Neugebauer Primaries (NPs). In certain examples, halftone levels for NPs are obtained for a halftone for printing an image. It is determined whether the halftone corresponds to a line or an area fill. The halftone levels may be adjusted in response to these levels exceeding a printing attribute threshold. The printing attribute threshold may be dependent on whether the halftone corresponds to a line or an area fill. The image may then be printed using the adjusted halftone levels.

Abstract: In some examples, a system receives image data for printing by a printer, and for a given colorant of a plurality of colorants to be used to print an image based on the image data, selects a plurality of different types of masks to use when dispensing printing fluid drops of the given colorant when printing the image. The system generates control data for printing the image using the selected plurality of different types of masks.

Abstract: Disclosed is a non-transitory computer readable storage medium, a computer-implemented method and an imaging color profile of an imaging apparatus. A processor retrieves the color profile of the imaging apparatus from data storage, the color profile comprising a first plurality of associations between a first plurality of color values in a first color space and a second plurality of color values in a second color space. The processor receives input data indicating a determined association, the determined association being an association between a first determined color value in the first color space and a second determined color value in the second color space. The processor performs an update process to update the first plurality of associations, the update process comprising performing an interpolation process using the determined association and an association of the first plurality of associations.

Abstract: A method is disclosed. According to some examples, the method comprises determining, by processing circuitry, a first element set to be associated with a print addressable location, the first element set comprising a first plurality of elements, wherein each element of the first plurality of elements identifies a print colorant or print colorant combination and is associated with a probability that the print colorant or print colorant combination identified by that element is to be applied to the associated print addressable location.

Abstract: In an example, a method includes determining, by processing circuitry, an element set to be associated with a print addressable location for printing an article in a one-pass print mode. The element set may comprise a plurality of elements, wherein each element identifies a print material or print material combination and is associated with a probability that the print material or print material combination identified by that element is to be applied to the associated print addressable location. Determining the element set for printing in a one-pass print mode may comprise favouring elements identifying individual print materials over elements identifying print material combinations.

Abstract: Examples of a method and a system measure colorimetric data of a set of color samples deposited on a reference substrate and on at least one further substrate having distinct colors from one another. Based on the measured colorimetric data, estimate functions are applied for mapping between the colorimetric data of the color samples deposited on differently colored substrates.

Abstract: Certain examples described herein relate to adjusting a printing system. In certain cases, a lookup table, LUT, is obtained where the lookup table comprises a plurality of nodes that map a plurality of input first color space values to a plurality of Neugebauer Primary area coverage, NPac, vectors in a second color space and each NPac vector comprises at least one Neugebauer Primary, NP. Each NPac vector in the LUT is adjusted by the determination of a colorimetric value of the NPac vector and the modification of the NPac vector based on a characteristic of the corresponding at least one NP and the colorimetric value such that the modification is specific to the NPac vector. The lookup table is updated with the modified NPac vector and stored for referral by the printing system in any future printing.

Abstract: Certain examples described herein relate to mapping between an input color space and an output color space. In some cases, data representing a set of candidate output color values in the output color space is obtained for a transition region between two input color values in the input color space. A sub-region of the transition region is defined, the sub-region being associated with a target colorimetry and a target value of a metric. An output color value is selected from the set of candidate output color values. The output value has an associated value of the metric and an associated colorimetry. The selecting is based on the associated colorimetry and the target colorimetry, and the value of the metric and the target value of the metric. In some cases, mapping data is generated by assigning the selected output color value to the sub-region.

Abstract: In an example, a print system includes a redundancy engine, a separation engine, and a print engine. In that example, the redundancy engine may identify a group of nozzles based on a redundancy characteristic of a plurality of print head nozzles of a print head to be received at the print head station and the separation engine may select a color separation operation corresponding to a drop domain associated with the group of nozzles identified by the redundancy engine to operate the print head with redundancy. In that example, the print engine may generate instructions using the selected color separation operation to cause the print head to eject print fluid from a combination of nozzles corresponding to the group of nozzles based on the drop domain to operate the print head with a redundancy print mode.

Abstract: In an example, a method includes determining, using processing circuitry, a first print coverage vector associated with an estimated colorimetry which corresponds to a target colorimetry, wherein the estimated colorimetry of the print coverage vector is based on a first color model, the first print coverage vector being optimised relative to a first metric. The method may further include determining, using processing circuitry, a predicted colorimetry of the first print coverage vector based on a second color model.

Abstract: In an example, a method includes accessing an initial prediction of a granularity metric for a halftone pattern. A correction factor to apply to the initial prediction may be determined, the correction factor being determined from a correction factor model defining a relationship between initial predictions of granularity metrics and human perceptions of granularity. The method may further include generating, using processing circuitry, a revised prediction of the granularity metric for the halftone pattern using the correction factor.

Abstract: A hybrid-masked halftone area Neugebauer separation (HANS) pipeline for a printing system is constructed. A number of Neugebauer Primaries (NPs) of and a halftone pattern to employ within the pipeline are selected according to specified ink interaction constraints during printing system ink output onto media, at a native resolution of the printing system. An NP area coverage (NPac)-based lookup table (LUT) and a pre-LUT color profile to employ within the pipeline are constructed according to first specified ink coverage and usage constraints during the ink output, at the native resolution. LUT post-processing and post-halftone pattern masking to employ within the pipeline are determined according to second specified ink coverage and usage constraints during the ink output, at the native resolution.