A method is described in which sets of corresponding colorimetric values are obtained. In a set, a colorimetric value is associated with a device color. A number of device colors are selected according to the color differences between colorimetric values associated with the same device color. A color calibration pattern is elaborated for a printer to be calibrated using the selected device colors and calibration is performed using the sets of colorimetric values.

An image processing apparatus configured to generate, using a target image data, multiple pieces of partial print data respectively for multiple partial printings such that, in a particular case where the color difference indicated by the evaluation value of the each of the partial images is larger than a particular reference value, a controller causes the image processing apparatus to identify, using the difference information, compensation target pixels including a pixel causing the color difference from among multiple pixels within the particular partial image, perform, using the difference information, a compensating process of converting a color of the compensation target pixel to a color of which color difference is small, and generate the partial print data using the particular partial image data to which the compensating process has been applied.

An image printed on a recording sheet is read, and the read image is displayed on a display unit. An instruction to use the displayed image as a correct answer image is accepted, and an image generated from the image that the instruction to use is accepted is registered as the correct answer image. A printed image is verified by comparing the printed image with the registered correct answer image.

An object of the present disclosure is to implement, at a low cost, highly accurate color calibration in a printing apparatus that performs printing using fluorescent ink. One embodiment of the present invention is an image processing apparatus that includes: a processing unit configured to perform processing relating to color calibration in a printing apparatus that prints an image on a printing medium using fluorescent printing material; and an execution unit configured to perform calibration processing of the printing apparatus based on a measured value that is obtained by measuring a patch chart for obtaining information on an amount of application of the fluorescent printing material in the printing apparatus, wherein a patch included in the patch chart is printed with the fluorescent printing material and subtractive color mixture printing material and at least one dot of the subtractive color mixture printing material covers a dot of the fluorescent printing material.

Provided is an image forming system including a first image forming device, a second image forming device; and an image reading device. A first hardware processor of the first image forming device causes a first image former of the first image forming device to form a first reference image on a first face of a sheet. A second hardware processor of the second image forming device causes a second image former of the second image forming device to form a second reference image different from the first reference image on the first face of the sheet. A third hardware processor of the image reading device determines whether an image positional deviation is present based on the first reference image and the second reference image that are formed on the first face of the sheet and that are read by the image reading device.

An image reading apparatus, having a placement table, a reader to read an image recorded on the recordable medium placed on the placement table while moving in one direction, a memory storing information concerning a test pattern, and a controller, is provided. The controller is configured to, when instructed to read the test pattern, control the reader to stop reading to pause before reading the test pattern completely, while the reader pauses, based on read data generated from an outcome of reading of the test pattern so far and the information concerning the test pattern, determine whether the read data satisfies a predetermined condition, and when the read data satisfies the predetermined condition, control the reader to resume reading the test pattern, but when the read data does not satisfy the predetermined condition, control the reader to abort reading the test pattern and output an error alerting signal.

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 generate a uniformity compensated halftone design for each of a plurality of pel forming elements, generate a missing neighbor corrected halftone design for each of the pel forming elements, generate a missing neighbor threshold lowering function for each of the pel forming elements based on the uniformity compensated halftone designs and the missing neighbor corrected halftone design and compute an average of the missing neighbor threshold lowering functions to generate an average missing neighbor threshold lowering function.

A printing system is disclosed. The printing system includes at least one physical memory device to store nozzle correction logic and one or more processors coupled with at least one physical memory device to execute the nozzle correction logic to receive a uniformity compensated halftone design for each of a plurality of pel forming elements, receive an average missing neighbor threshold lowering function, receive a defective nozzles list including one or more of the plurality of pel forming elements indicated as defective during print production and perform missing neighbor processing by applying the average missing neighbor threshold lowering function associated with a pel forming element determined to be a neighbor of a defective pel forming element.

An image reading device includes a reading unit, a background member, and processing circuitry. The reading unit includes alight source to emit light to a passage area through which an object passes and an imaging device to capture reflected light of the light emitted to generate a visible image and an invisible image. The background member is disposed opposite the light source across the passage area. The processing circuitry is configured to: detect a change in an image characteristic due to a change in an optical characteristic of the reading unit, in invisible images obtained by capturing of invisible marks on the background member; determine a correction amount of an image characteristic to be used for correcting an image of the object generated by the imaging device, based on the change in the image characteristic detected; and correct the image characteristic based on the correction amount determined.

An image abnormality detecting device includes an image reader, an abnormality detector, a pattern holder, and circuitry. The image reader is configured to read an image on a recording medium. The abnormality detector is configured to detect abnormality of the image based on read information of the image on the recording medium, read by the image reader. The pattern holder has a check pattern and is disposed within a reading area of the image reader. The circuitry is configured to inspect a detecting operation of the abnormality detector based on read information of the check pattern read by the image reader.