A method is disclosed. The method comprises receiving a matrix representation of a source image to be printed, the matrix representation defining a colorant value for each of a plurality of print addressable locations, wherein the colorant values are representative of amounts of print colorant to be delivered to the print addressable locations during a printing operation. The method may comprise identifying, by processing circuitry, a region in the matrix representation having a first print addressable location and an adjacent second print addressable location, wherein a difference between colorant values of the first print addressable location and the second print addressable location meets or exceeds a defined colorant value threshold. The method may comprise determining, by processing circuitry, an amount of treatment fluid to be delivered to each of the plurality of print addressable locations during the printing operation, wherein an amount of treatment fluid to be delivered in the identified region is determined to be greater than an amount of treatment fluid to be delivered to adjacent print addressable locations having colorant values which differ by less than the defined colorant value threshold. An apparatus and a machine-readable medium are also disclosed.

A printing apparatus includes a print execution section and a controller. The print execution section includes: a printing head having nozzles arranged in a first direction; a head driver that drives the printing head to discharge ink from the nozzles thereby forming dots on a printing medium; and a movement mechanism that moves the printing medium relative to the printing head in any of the first direction and a second direction intersecting with the first direction. The controller obtains a piece of object image data, generates, by using the object image data, a plurality of pieces of dot data indicating formation states of the dots for pixels, and prints a printing image by causing the print execution section to execute discharge of the ink and movement of the printing medium by use of the pieces of dot data.

Embodiments of the present disclosure provide an image calibration method, an image forming apparatus, and a storage medium. The method includes outputting a calibration image in response to a calibration instruction, where the calibration image includes a calibration pattern and a calibration mark; according to the calibration mark of the calibration image, determining whether a calibration event corresponding to the calibration image matches a calibration event corresponding to a current calibration operation, or determining whether a calibration event type corresponding to the calibration image matches a calibration event type corresponding to a current calibration operation; and performing image calibration according to the calibration pattern in the calibration image if the calibration event corresponding to the calibration image matches the calibration event corresponding to the current calibration operation, or if the calibration event type corresponding to the calibration image matches the calibration event type corresponding to the current calibration operation.

Embodiments of the present disclosure provide an image calibration method, an image forming apparatus, and a storage medium. The method includes outputting a calibration image in response to a calibration instruction, where the calibration image includes a calibration pattern and a calibration mark; according to the calibration mark of the calibration image, determining whether a calibration event corresponding to the calibration image matches a calibration event corresponding to a current calibration operation, or determining whether a calibration event type corresponding to the calibration image matches a calibration event type corresponding to a current calibration operation; and performing image calibration according to the calibration pattern in the calibration image if the calibration event corresponding to the calibration image matches the calibration event corresponding to the current calibration operation, or if the calibration event type corresponding to the calibration image matches the calibration event type corresponding to the current calibration operation.

In some examples, a device includes a printing device to generate an image on a substrate from a digital image, and a processor to: receive a scanned image of the image on the substrate, identify a plurality of image portions of the scanned image, identify horizontal color changes across a horizontal portion of the plurality of image portions, identify vertical color changes across a vertical portion of the plurality of image portions, compare the horizontal color changes and vertical color changes to corresponding horizontal color changes and corresponding vertical color changes of the digital image, and measure a presence of color plane misregistration, and the color, direction and magnitude of misregistration based on the comparison.

In some examples, a device includes a printing device to generate an image on a substrate from a digital image, and a processor to: receive a scanned image of the image on the substrate, identify a plurality of image portions of the scanned image, identify horizontal color changes across a horizontal portion of the plurality of image portions, identify vertical color changes across a vertical portion of the plurality of image portions, compare the horizontal color changes and vertical color changes to corresponding horizontal color changes and corresponding vertical color changes of the digital image, and measure a presence of color plane misregistration, and the color, direction and magnitude of misregistration based on the comparison.

A method of operating a printer separates the image data content of a sheet in a print job into multiple color separations. The first color separation printed on the sheet includes at least two fiducials printed in the least perceptible color of ink in the printer. The at least two fiducials are used to identify the process direction and skew of the printed sheet before the remaining color separations are printed on the sheet with the first color separation.

A method of operating a printer separates the image data content of a sheet in a print job into multiple color separations. The first color separation printed on the sheet includes at least two fiducials printed in the least perceptible color of ink in the printer. The at least two fiducials are used to identify the process direction and skew of the printed sheet before the remaining color separations are printed on the sheet with the first color separation.

Example implementations relate to adjust sharpness parameters. In some examples, a printing device can include a processing resource and a memory resource storing non-transitory machine-readable instructions to cause the processing resource to receive print data comprising color channels corresponding to print pixels to be formed on a multi-layer thermally activated print medium, determine a characteristic of a corresponding layer of the multi-layer thermally activated print medium for color channels of the received print data, adjust sharpness parameters of the color channels based on the determined characteristic of the corresponding layer of the multi-layer thermally activated print medium, and cause a print head of the printing device to apply thermal energy to an area of the multi-layer thermally activated print medium including the print pixels using the adjusted sharpness parameters.

A purple-fringe correction method includes determining: (1) a first distance between a first pixel in a purple-fringe area in an image and an overexposed area in the image and (2) a second distance between the first pixel and a non-overexposed, non-purple-fringe area in the image. The first pixel in the purple-fringe area is corrected based on the first distance and the second distance.