Hewlett-packard Development Company, L.p.

Pere Gasparin Talarn

Jan Morovic

Peter Morovic

Javier Maestro Garcia

Juan Uroz Soria

Antonio Gracia Verdugo

Li Qian

Jacint Humet Pous

Victor Diego Gutierrez

Sergio Etchebehere Juan

Jacint Humet

Maxime Rosello

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

An example of a color management module is disclosed. The color management module is to generate a mapping from an incoming color space to a printer color space by a color pipeline. In the generation of the mapping, the color pipeline is adjusted so that the mapping of a target color associated with a first composition further includes adding a quantity of a second composition to the mapping of the target color. The second composition comprises a lower visibility than the first composition.

Color pipeline

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

Example implementations relate to color compensation. Some examples may print a calibration target background on a non-opaque media. The calibration target background may have a color that increases a dynamic range of a set of color measurements of a calibration target foreground. Some examples may print the calibration target foreground over the calibration target background. Additionally, some examples may measure an optical density of the calibration target foreground with a reflective sensor and may calibrate a printer based on the measured optical density.

Color calibration

Techniques related to printer calibration are disclosed herein. In an example, an actual measurement of a colorimetric parameter is performed by measuring the colorimetric parameter on a printed calibration pattern. The colorimetric parameter is associated with an ink drop number. The calibration pattern is printed with selected printing conditions. An ink drop number variation is determined from a reference measurement and the actual measurement of the colorimetric parameter. The reference measurement is a measurement of a colorimetric parameter. The reference measurement corresponds to a measurement of the colorimetric parameter on a calibration pattern printed with the selected printing conditions. An actual linearization is generated by validating a set of pre-defined linearizations with the determined ink drop number variation. Other examples of printer calibration are disclosed.

Growing community of inventors

Sant Cugat del Valles, Spain

Pere Gasparin Talarn