Abstract: Methods and apparatus associated with three-dimensional objects are described. In an example, a method comprises receiving data representing a three-dimensional model object, the data comprising object model data and object property data. For at least one object property, a sub-region of the object in which the object property is non-variable is identified and, for at least one location within the object, all sub-regions in which the location is situated are identified. Based on the combination of identified sub-regions for a location, print material data is determined for the location. Control data for the production of a three-dimensional object is generated according to the print material data.

Abstract: Example methods of controlling printing of a halftone image are disclosed as well as apparatuses and computer-readable storage mediums relating thereto. In an example, the method includes receiving input data indicating a first colorant deposition order for a colorant combination and a second colorant deposition order for the colorant combination, wherein the second colorant deposition order is different from the first colorant deposition order. Control data is generated based on the input data. The control data includes first pixel data associating a first pixel in the halftone image with the first colorant deposition order, and second pixel data associating a second pixel in the halftone image with the second colorant deposition order. The control data is used to control a printer to print the halftone.

Abstract: A method for setting properties of a three-dimensional object in an additive manufacturing process, e.g. 3D-Printing, in which data representing a three-dimensional object to be printed is obtained. The data comprises sub-volumes representing the three-dimensional object. The position of the sub-volumes in the three-dimensional object is identifyied by a positional pomponent, i.e. a location depth and an orientation angle. A characteristic for the three-dimensional object to be printed is identified or set by the user. The property data is set for individual sub-volumes to be used in printing the three-dimensional object based on the identified characteristic and positional component. The property data comprises material property data, structural property data and printing property data.

Abstract: Certain examples described herein relate to the preprocessing of object data for the manufacture of a three-dimensional object. In one case, the object data represents at least a first and a second object portion, the first object portion being associated with a first production material composition and the second object portion being associated with a second production material composition. The first and the second object portions may be arranged such that they comprise a contiguous interface. In certain described cases, the object data is modified by modulating the contiguous interface. Said modulating the contiguous interface may comprise modulating data defining at least one of the first and the second object parts such that a portion of at least one of the first and second production material compositions extends into object space occupied by a respective one of the second and first object parts. The resultant modified object data may be used to manufacture the three-dimensional object.

Abstract: A method of calibrating an area coverage representation of a color. A first area coverage of a Neugebauer primary in an area coverage representation of a color is determined based on a plurality of reference area coverage parameters for the Neugebauer primary, wherein each reference area coverage parameter in the plurality of reference area coverage parameters corresponds to a respective colorant deposition subsystem in a plurality of colorant deposition subsystems. A second area coverage of the Neugebauer primary is determined based on the plurality of reference area coverage parameters and a plurality of calibration parameters for the Neugebauer primary, wherein each calibration parameter in the plurality of calibration parameters corresponds to a respective colorant deposition subsystem in the plurality of colorant deposition subsystems.

Abstract: A printer apparatus comprises one or more ports (2011 to 201M) for receiving one or more colorant units (INK1 to INKN), and a processing unit. The processing unit is adapted to determine which one or more colorant units (INK1 to INKN) have been loaded into the printer apparatus. The processing unit is adapted to retrieve colorant information from each loaded colorant unit (INK1 to INKN), and determine an ink-set configuration using the colorant information retrieved from each loaded colorant unit (INK1 to INKN). Operation of the printer apparatus is configured according to the determined colorant-set configuration.

Abstract: In an example, a method includes determining a plurality of print coverage vectors, each of the print coverage vectors specifying a common amount of a selected print agent. The method may further comprise determining a colorimetry provided by each of the print coverage vectors and dividing a range of colorimetries into partitions in a colorimetric space. For each of a plurality of the partitions, the method may include determining a characteristic of each print coverage vector resulting in a colorimetry within that partition and selecting a print coverage vector for that partition based on the determination. A color mapping resource may be determined based on the selected print coverage vectors.

Abstract: Certain examples described herein relate to generating a Neugebauer Primary area coverage (NPac) vector. In certain cases, a first plurality of Neugebauer Primaries (NPs) defined by a first NPac vector is determined, the first plurality of NPs defining a set of characteristics of a printing process. A second NPac vector, defining a second plurality of NPs, is generated based on the set of characteristics and a criterion relating to the printing process.

Abstract: 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.

Abstract: Methods for printer color calibration are disclosed. A nominal Neugebauer Primary area coverage (NPac) vector from an NPac space is then determined from a color mapping, the nominal NPac vector corresponding to a given color value in a color space. One or more colorant calibration factors each associated with a color of colorant are received; the calibration factors representing operational characteristics of the printer. One or more optimization metrics for constraining desired properties of an objective calibrated NPac vector to be generated are also received. The calibrated NPac vector is generated based on the nominal NPac vector such that: the generated calibrated NPac vector is convex; and for each given color of colorant the usage of colorant associated with the generated calibrated NPac vector is equal to the product of usage of colorant associated with the nominal NPac vector; and the calibration factor for the given color of colorant.

Abstract: In some examples, a plurality of print material combinations for object generation are determined, each print material combination having an associated color. A plurality of color descriptions may be determined, the color descriptions corresponding to a combination of voxels, each of the voxels of the combination of voxels having a defined print material combination and a defined depth with respect to a surface. A color mapping resource may be defined, the color mapping resource associating a color description with a print instruction, each print instruction being for use in causing an object generation apparatus to generate the combination of voxels corresponding to the associated color description.

Abstract: A method is described. The method comprises determining a lightness coordinate value corresponding to a first color value along a black-white axis in an input device color space. A set of color values corresponding to the lightness coordinate value, in the input device color space is determined. A subset of the set, based on the respective angular positions of the color values in the set and an angular position of the first color value is determined. The method comprises deriving a set of print color space values of a target printing system comprising print color space values corresponding to the subset and a color value corresponding to the position of the lightness coordinate value, based on a predetermined association between input device color space values and print color space values. The method comprises determining a given print color space value corresponding to the first color value based on the derived set of print color space values.

Abstract: Cells of an n-dimensional object are indexed. A plurality of indexing digits are grouped for each axis of the n dimensions of the n-dimensional object. A first indexing digit of a given group is allocated to each of at least two cells resulting from at least one subdivision of the dimension of the object along the axis of the given group; and an mth subsequent indexing digit of the given group is allocated to any subsequent at least two cells resulting from any subsequent at least one subdivision of at least one cell of the at least two cells resulting from the m?1th subdivision of the dimension of the object along the axis of the given group.

Abstract: According to examples, area coverage vectors for each pixel on each slice of a digital representation of an object may be determined and a two-dimensional halftone matrix including threshold values may be subdivided into a plurality of sub-matrices, each sub-matrix including threshold values of the halftone matrix in a respective value sub-range. In addition, for each of the slices, a sub-matrix of the plurality of sub-matrices may be selected and the area coverage vectors for the pixels in the slice may be halftoned using respective threshold values of the selected sub-matrix.

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: A method of generating a set of halftone parameters. The method comprises assigning a first set of halftone parameters to a first location in a color space, the first location in the color space corresponding to a first color, and assigning a second set of halftone parameters to a second location in the color space, the second location in the color space corresponding to a second color. An interpolating between the first set of halftone parameters and the second set of halftone parameters is performed, based on the first location and the second location, to determine a third set of halftone parameters corresponding to a third location in the color space. The result of the interpolation is output data associating the third set of halftone parameters with a third color corresponding to the third location in the color space.

Abstract: A method is disclosed in which a lookup table (LUT) that maps chromatic and achromatic device color space vectors into Neugebauer primary area coverages (NPacs) is obtained. According to the method, a LUT that maps chromatic device color space vectors into NPacs is combined with a LUT that maps achromatic device color space vectors into NPacs.

Abstract: An example method of linearizing print outputs for a printing system is described. The method involves retrieving a look-up table comprising a plurality of nodes that map input space values to Neugebauer Primary Area Coverage vectors. The printing system is used to print a set of ramps, each ramp comprising a plurality of test areas. The test areas for each ramp are defined by varying vector element values corresponding to input space values that vary in a dimension of the input space. A property of each of the printed test areas is measured and a linearization function is determined based on those measured properties. The linearization function is then applied to the input space values for the plurality of nodes in the look-up table.

Abstract: In one example, a method comprises receiving data representing a first property of a three-dimensional object generated by a print apparatus, the data having been determined by measurement of the object. A difference between the data representing a first property and predetermined data may be determined, and, based on the difference, an estimate of a second property of the object may be determined.

Abstract: Certain examples described herein relate to the embedding a pattern in an output content having at least two-dimensions, for example a printed output. Content data having at least two dimensions is processed to generate an array of spatial elements, each spatial element corresponding to a respective location in the output content and comprising a probabilistic distribution for a set of output material compositions. A threshold matrix is generated using pattern data corresponding to a pattern, and the array of spatial elements is halftoned using the threshold matrix. The threshold matrix is generated such that the pattern is embedded in the output content.