A method and system for detecting one or more failing nozzles in an inkjet printhead of an inkjet printer for printing an image on a substrate and compensating failing nozzles, as well as for correcting colour uniformity of a printed image in inkjet printing an image on a substrate includes printing a first test pattern on a dedicated substrate, which is optically scanned and includes a system for the same. From the scan failing nozzles are identified, which are to be compensated by other nozzles. To these compensating nozzles compensated nozzle control data are allocated, which are used in printing a second test pattern that is also scanned and analysed for local deviations of colorimetric greyscale value. Corrected nozzle control data are allocated to the nozzles associated with the local deviation.

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.

An image processing apparatus corrects a measured value obtained by measuring a measurement image formed using a printing element configured to discharge ink, the measured value being used to identify a density characteristic of the printing element. The image processing apparatus obtains a measured value; and corrects the measured value based on a density of the measurement image.

A printing system is disclosed. The printing system includes at least one physical memory device to store calibration logic and one or more processors coupled with the at least one physical memory device to execute the calibration logic to perform uniformity compensation of a plurality of secondary colors printed by pel forming elements, each of the pel forming elements associated with one of a plurality of primary colors, including generating a uniformity compensated first primary color transfer function for each of the pel forming elements associated with a first primary color and a uniformity compensated second color transfer function for each of the pel forming elements associated with a second primary color, generating an updated uniformity compensated first primary color transfer function for each of the pel forming elements associated with the first primary color and a uniformity compensated third primary color transfer function for each of the pel forming elements associated with a third primary color and generating an updated uniformity compensated second primary color transfer function for each of the pel forming elements associated with the second primary color and an updated uniformity compensated third primary color transfer function for each of the pel forming elements associated with a third primary color.

In one example in accordance with the present disclosure, a printing device is described. The printing device includes a print controller with a processor and memory. The print controller generates print instructions. Specifically, the print controller receives print image data representing an image to be printed and identifies enclosed regions in a background print agent plane. The print controller also determines a size of the enclosed regions of background print agent plane and responsive to the size of an enclosed region being smaller than a threshold size, removes the enclosed region from the background print agent plane. The printing device also includes a print agent distribution system to apply the background print agent and the image print agent to a substrate according to the print instructions.

A printing system is disclosed. The printing system includes at least one physical memory device to store calibration logic and one or more processors coupled with the at least one physical memory device to execute the calibration logic to perform uniformity compensation of a plurality of secondary colors printed by pel forming elements, each of the pel forming elements associated with one of a plurality of primary colors, including generating a uniformity compensated first primary color halftone design for each of the pel forming elements associated with a first primary color and a uniformity compensated second color halftone design for each of the pel forming elements associated with a second primary color based on an inverse transfer function corresponding to a first secondary color, generating an updated uniformity compensated first primary color halftone design for each of the pel forming elements associated with the first primary color and a uniformity compensated third primary color halftone design for each of the pel forming elements associated with a third primary color based on an inverse transfer function corresponding to a second secondary color and generating an updated uniformity compensated second primary color halftone design for each of the pel forming elements associated with the second primary color and an updated uniformity compensated third primary color halftone design for each of the pel forming elements associated with a third primary color based on an inverse transfer function corresponding to a third secondary color.

A system is disclosed. The system includes at least one physical memory device to store calibration logic and one or more processors coupled with the at least one physical memory device to execute the calibration logic to receive an image having a blended input color comprising a first primary color value and a second primary color value, generate blend weights for the blended input color based on the first primary color value and the second primary color value, receive a plurality of transfer functions corresponding to each of the first primary color value and the second primary color values and apply the blend weights and the plurality of transfer functions to the first primary color value and the second primary color value to generate a uniformity corrected first primary color value and a uniformity corrected second primary color value associated with the blended input color.

An information processing apparatus is provided. The apparatus comprises at least one memory; and at least one processor, wherein the at least one memory stores at least one program that causes the at least one processor to perform operations including acquiring, periodically, in response to a request, or both, a color verification result of a printed article printed by an image forming apparatus from a storage storing a color measurement result of a printed article printed by the image forming apparatus, and in a case where the color verification result for the image forming apparatus to execute an instructed image forming satisfies a reference, executing the instructed image forming.

A printing system is disclosed. The printing system includes at least one physical memory device to store calibration logic and one or more processors coupled with the at least one physical memory device to execute the calibration logic to perform uniformity compensation of a plurality of secondary colors printed by pel forming elements, each of the pel forming elements associated with one of a plurality of primary colors, including generating a uniformity compensated first primary color transfer function for each of the pel forming elements associated with a first primary color and a uniformity compensated second color transfer function for each of the pel forming elements associated with a second primary color, generating an updated uniformity compensated first primary color transfer function for each of the pel forming elements associated with the first primary color and a uniformity compensated third primary color transfer function for each of the pel forming elements associated with a third primary color and generating an updated uniformity compensated second primary color transfer function for each of the pel forming elements associated with the second primary color and an updated uniformity compensated third primary color transfer function for each of the pel forming elements associated with a third primary color.

A nail polish application apparatus, comprising a mounting element comprising a capsule compartment adapted to receive one or more capsules containing a nail polish fluid wherein the mounting element is moveable by actuator(s) in longitudinal axis crossing a nail polish applying space and in lateral axis perpendicular to the longitudinal axis and is rotatable by the actuator(s) around the longitudinal axis, a pressure applying element adapted to apply pressure on a body portion of the capsule(s) installed in the capsule compartment wherein the body portion defines a reservoir containing a nail polish fluid, the pressure builds an internal pressure in the reservoir forcing extrusion of the nail polish fluid to a nail polish applying element integrated with the capsule(s), sensor(s) adapted to generate sensory data depicting the nail polish applying space and a control unit adapted to operate the actuator(s) and the pressure according to analysis of the sensory data.