Hewlett-packard Development Company, L.p.

Other

Peter Morovic

Jan Morovic

Juan Manuel Garcia Reyero Vinas

Jordi Arnabat Benedicto

Javier Maestro Garcia

Marti Rius Rossell

Hector Gomez Minano

Jay Stephen Gondek

Scott A White

Sergio Etchebehere Juan

Jun Zeng

Michel Georges Encrenaz

Victor Diego Gutierrez

Montserrat Solano Pallarol

Xavier Farina Vargas

Peter J Klammer

James William Stasiak

Ingeborg Tastl

Joan Vidal Fortia

Johan Maurice Lammens

Jordi Vilar Benito

Manuel Angel Albarran Moyo

Jordi Vilar

Juan Manuel Garcia Reyero Viñas

Matthew Donald Gaubatz

Alejandro Manuel De Pena

Utpal Kumar Sarkar

Lluis Abello Rosello

Andreas Muller

Pere Gasparin Talarn

Martí Rius Rossell

Juan Manuel García Reyero Viñas

Lihua Zhao

William James Allen

Ronald Albert Askeland

Paolo Faraboschi

Nathan McPherson Moroney

Paul J Benning

Jacob Wright

Andrew E Fitzhugh

Melanie M Gottwals

Marcos Casaldaliga Albisu

Sebastia Cortes

Alex Andrea Tallada

Alex Campa Coloma

Juan Uroz

Pu Huang

Karl Walters

Pau Costal Fornells

Yvan Richard

Josep Abad Peiro

David Gaston Llado

Adam Peter Franks

Juan Manuel Garcia

Juan Manuel Garcia Reyero

Joan Jordi Coll Sicluna

Juan Manuel Garcia-Reyero Vinas

Alejandro Manuel De Peña Hempel

Manuel Ángel Albarrán Moyo

Marti Maria Saquer

Pere Josep Canti Nicolas

Joan Vidal

Alessandro Beltrami

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.

Printing modes with drying delays

Systems, apparatuses, and methods may provide for technology to control the printing of halftoning screen signatures for various levels of prints. For example, such prints may include regular edition prints or limited edition prints. During printing, a first halftoning screen is associated with one or more of the regular edition prints and a second halftoning screen is associated with the limited edition print, in some implementations. The second halftoning screen has a spatial frequency that is substantially the same as the first halftoning screen while having a spatial signature different from the first halftoning screen. Additionally, the second halftoning screen further may have spectral properties that are substantially the same as the first halftoning screen. During printing, two different printed copies of an image are formed using the first halftoning screen and the second halftoning screen.

Custom halftone for limited edition prints

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.

Neugebauer primaries halftone level adjustment

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.

Printing management

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.

Encoding plural colorant vectors in a Neugebauer Primary area coverage vector

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.

Color calibration in a printing system

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.

Mapping between color spaces

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.

Redundancy print modes

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.

Hybrid-masked halftone area Neugebauer separation (HANS) pipeline

Certain examples relate to emulating a spectral measurement device in a color measurement apparatus. In these examples, a primary spectral measurement device measures a first spectral characteristic of a rendered color output. A predictive model, parametrized by parameter values, is applied to the measurement from the primary spectral measurement device to determine a predicted measurement of a second spectral characteristic of the rendered color output which would be measured by an ancillary spectral measurement device. Parameter values are generated by training the predictive model with data from the primary spectral measurement device and the ancillary spectral measurement device.

Emulating a spectral measurement device

Certain examples described herein relate to generating a Neugebauer Primary area coverage (NPac) vector. In certain cases, an operating state of a printing system is determined. A first NPac vector is obtained, having an initial set of Neugebauer Primaries (NPs). The initial set of NPs comprise a NP that is not implementable with the operating state. A target set of NPs is determined on the basis of the operating state, the target set of NPs being implementable with the operating state. A second NPac vector is generated, the second NPac vector having the target set of NPs.

Generating an area coverage vector

A method in described in which a halftone matrix is generated using a kernel by mapping kernel values of each pixel to a halftone matrix value at a corresponding element of the halftone matrix. Where a plurality of pixels have the same kernel value, the kernel value is randomly mapped to a respective halftone matrix value in a range of halftone matrix values corresponding to the kernel value.

Halftone matrix generation using kernels

Certain examples described herein relate to printer calibration. In some cases, adjustment data is received, indicating an adjustment to be applied to a given colorant. A Neugebauer Primary area coverage (NPac) vector defining an operating set of Neugebauer Primaries (NPs) is obtained. Configuration data is determined, dependent on the operating set of NPs. The configuration data maps colorant adjustments to relationships between NPs in the operating set, for both an increase and a decrease in the given colorant. In some cases, the configuration data and the adjustment parameters are used to identify first and second subsets of the operating set of NPs. The NPac vector is adjusted by decreasing an area coverage of an NP in the first subset and complementarily increasing an area coverage of an NP in the second subset.

Printer calibration

In an example, a method includes acquiring data representing an article to be printed, the data comprising an element set associated with a print addressable location, the element set comprising a first element subset and a second element subset, wherein the first element subset and the second element subset comprise an element identifying a print material selection which is associated with a probability that the print material selection is to be applied to the associated print addressable location. The method further includes determining a first set of cumulative probability values associated with the elements of the first element subset and determining a second set of cumulative probability values associated with the elements of the second element subset. The first set of cumulative probability values may span a first predetermined value range and the second set of cumulative probability values may span a second predetermined value range.

Determining cumulative probability values for subsets of elements

There are disclosed techniques for error diffusion for printing. For example, there is disclosed a device comprising a pixel selector, to select a pixel from an image to be printed, wherein the pixel is associated to a group of device state probabilities, wherein each device state probability describes a probability of choosing a particular device state, wherein each device state describes the quantity of each colorant to be used in correspondence of the pixel. The device may comprise a device state determiner, to choose the device state for the selected pixel on the basis of the device state probabilities associated to the selected pixel. The device may comprise a feedback chain, to diffuse device state probability errors to pixels to be subsequently selected. The feedback chain may include a selected pixel error determiner, to determine device state probability errors for each device state probability of the selected pixel. The feedback chain may include a neighbouring pixel selector, to choose neighbouring pixels among the pixels to be subsequently selected. The feedback chain may include a neighbouring pixel error modifier, to modify, for each neighbouring pixel, the determined device state probability errors according to criteria conditioned by metrics and/or classification data associated to the selected pixel and/or a group of previously selected pixels and the relative position between the neighbouring pixel and the selected pixel. The feedback chain may include an error diffuser, to diffuse the modified device state probability errors to the neighbouring pixels.

Error diffusion for printing

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Sant Cugat del Valles, Spain

Peter Morovic