An image processing control apparatus includes a hardware processor. The hardware processor obtains: read image data obtained through reading a color sample and shown in a first color system; original image data corresponding to the color sample and shown in a second color system; and region-by-attribute information indicating a first region corresponding to spot-color printing and a second region corresponding to decoration printing, the first and second regions being in the original image data. The hardware processor determines a color conversion parameter for color conversion of the first region and a color conversion parameter for color conversion of a third region different from the first and second regions in the original image data by using the read image data. The hardware processor determines a color conversion parameter for color conversion of the second region according to predetermined values shown in the second color system.

Certain examples relate to the processing of spot colors within a printing pipeline. In these example, a palette of spot colors indicated in a print job is determined. The palette is mapped to a set of vectors in a colorant-dependent color space based on a comparison of target spectral characteristics for the spot colors and measured spectral characteristics of the printing system. The set of vectors is used to assign vectors to print-resolution areas of the print job before halftoning.

In an image recording apparatus, when an image is recorded on a recording medium, the recording medium passes through a head part only once. Before the image is recorded, a value of a color component of at least some of pixels included in the image is corrected in order to reduce color mixing unevenness. At that time, on the basis of respective values of two reference color components among a plurality of color components of a correction target pixel, a value of one target color component included among the two reference color components is corrected. Alternatively, on the basis of respective values of three reference color components among the plurality of color components, a value of one target color component or respective values of two target color components included among the three reference color components are corrected.

Certain examples described herein relate to printer calibration. In certain cases, measurement data is received, the measurement data indicative of an adjustment to be applied to a given colorant in a set of colorants printable by a printing system. In certain examples, a Neugebauer primary area coverage (NPac) vector comprising an area coverage of a first Neugebauer primary (NP) is obtained. Based on the received measurement data, the NPac vector is adjusted by decreasing the area coverage in the NPac vector of the first NP and increasing an area coverage in the NPac vector of a second NP. The first NP and the second NP correspond to colorant combinations that differ by a predetermined amount of the given colorant.

On the basis of a first calibration point corresponding to a reflectance of a state where a target ink or the like is applied on a transparent ink and a second calibration point corresponding to a reflectance of a state where the target ink is applied on a black ink that is applied on a base material, a third calibration point corresponding to a reflectance of a state where the target ink is solidly applied on a background having an average reflectance is obtained. A reflectance as a prediction value of a color corresponding to the reflectance of the entire background is obtained on the basis of the third calibration point and a fourth calibration point corresponding to a reflectance of a state where the target ink is applied on the base material.

An image processing apparatus includes an image forming device, a reading device, and circuitry. The image forming device is configured to form a first pattern on a recording medium. The first pattern includes a plurality of patches in a plurality of tones. The reading device is configured to read the first pattern. The circuitry is configured to acquire read data of the first pattern from the reading device. The read data includes red, green, and blue (RGB) color space values. The circuitry is further configured to: correct the read data based on information indicating a relationship between a color and a position in the first pattern to reduce variation in readings due to a read position of the first pattern; convert the read data corrected into device-independent data; and adjust a color reproduction characteristic of the image forming device based on the device-independent data.

A color inspection device includes a reading device and circuitry. The reading device images a reference object and a color detection object to obtain readings of each of the reference object and the color detection object. The circuitry corrects the readings of the color detection object by using a correction coefficient that is generated from the readings of the reference object and color information measured for each arbitrary region of the reference object.

An image processing apparatus includes circuitry configured to provide information in response to satisfaction of a given condition. The information indicates that a mixed-color characteristic is to be corrected.

A layer configuration prediction method is provided and includes: a specimen production step of producing multiple specimens by depositing layers of a material in configurations different from each other; a specimen measurement step of performing, on each specimen, measurement to acquire a texture parameter corresponding to a texture; a learning step of causing a computer to perform machine learning of a relation between each of the specimens and the texture parameter; a setting parameter calculation step of calculating a setting parameter corresponding to the texture set to a computer graphics image; and a layer configuration acquisition step of providing the setting parameter as an input to the computer having been caused to perform the machine learning, and acquiring an output representing the layering pattern of layers of the material corresponding to the setting parameter.

First, a color close to a prediction target color is selected as a similar color from among a plurality of sample colors for which spectral reflectances of a plurality of patches are obtained. Next, for a similar color, a relational equation representing the relationship between the spectral reflectances of a solid patch (a patch with the highest ink density) and the spectral reflectances of a color prediction target patch is obtained. Finally, the spectral reflectances of the solid patch for the prediction target color are applied to the relational equation, by which predicted values of spectral reflectances of the color prediction target patch for the prediction target color are obtained.