Aspects of the disclosure provide for a method. In some examples, the method includes printing a target plot comprising a color ramp, scanning the target plot via a first image scanner to determine first scan results indicating a relationship between a scanned measurement determined by the first image scanner and lightness of a scanned portion of the target plot, scanning the target plot via a second image scanner to determine second scan results indicating a relationship between a scanned measurement determined by the second image scanner and lightness of the scanned portion of the target plot, and determining a lookup table indicating a difference determined based on the first scan results and the second scan results.

An image processing apparatus comprises: an image forming unit configured to form an image on a recording medium using a plurality of color materials on the basis of first image data showing an image; and an estimating unit configured to estimate a characteristic of each one of the plurality of color materials in a target region on the formed image on the basis of second image data obtained by reading the formed image. The estimating unit selects an estimation processing unit to use from among a plurality of estimation processing units used for different estimation methods on the basis of a combination of the color materials in the target region.

There is provided a printing apparatus including an obtaining unit configured to obtain print data in which in imposition image data in which one or more images are imposed in a print region, a code for identifying each image in the imposition image data is embedded; a determination unit configured to determine an ink color to be used to print the code by excluding an ink color satisfying a predetermined condition from candidates for the ink color to be used to print the code; and a print control unit configured to print the code based on the print data obtained by the obtaining unit using a plurality of nozzle arrays for the ink color determined by the determination unit.

An apparatus comprises a unit configured to generate gradation data corresponding to an achromatic color generated by combining two or more colors among a plurality of colors, for an excess amount of a total gradation value exceeding a predetermined value, the total gradation value being a sum of gradation values of the plurality of colors used for recording a pixel of interest, and generate gradation data corresponding to the plurality of colors, based on the generated gradation data corresponding to the achromatic color; and a unit configured to quantize the generated gradation data, and generate data to control recording of dots corresponding to the pixel of interest. The predetermined value is a gradation value indicating whether or not to record the dots in an overlapping manner, in case that the dots corresponding to the total gradation value are recorded.

An apparatus for image conversion includes a processor configured to classify a reference region representing a predetermined feature into a shadowed region and an unshadowed region, the reference region being in an aerial image represented in RGB color space; determine a tone correction factor so that a difference between an average luminance of the shadowed region and an average luminance of the unshadowed region in the aerial image represented in predetermined color space to which the color space of the aerial image is converted from RGB color space is less than a difference between an average luminance of the shadowed region and an average luminance of the unshadowed region represented in RGB color space; correct tones of the aerial image with the tone correction factor; and convert the color space of the aerial image from RGB color space to the predetermined color space to generate a color conversion image.

An image forming apparatus includes first and second processors controlling first and second image formers that form first and second images using color material having first and second color compositions, the second image to be superimposed on the first image; and a display displaying information. If an image formation instruction, including information indicating that the first and second images are to be superimposed is received, with a different image formation instruction being received, the first processor causes the first image former to form the first image in accordance with a first image formation instruction, corresponding to the first color composition, out of the image formation instruction and the different image formation instruction; and transmit to the second processor a second image formation instruction corresponding to the second color composition. The second processor causes the second image former to form the second image in accordance with the second image formation instruction.

An image processing apparatus includes a processor configured to generate a second color chart from a first color chart. The second color chart includes multiple color samples selected from multiple color samples included in the first color chart, and the second color chart is generated in such a manner that a color sample included in the second color chart is located in the second color chart at a position at least maintaining a partial-adjacency relationship in the first color chart.

According to the invention, the saturation thresholds (th.sub.r; th.sub.g; th.sub.b) used for this detection depend on color coordinates (r.sub.w, g.sub.w, b.sub.w) representing an illuminant (ILL) of the image.

An image forming apparatus includes: a scanner to read each of a first output product serving as a model and a second output product output from the image forming apparatus; a memory that stores a color conversion lookup table to be used when color conversion is performed from a RGB color system into a CMYK color system; and circuitry to correct the color conversion lookup table based on a number of pixels and an amount of change per hue, using read information on the first output product, and re-correct the corrected color conversion lookup table, using read information on the second output product.

The invention provides a control method including: obtaining color information to be printed in the specific color out of color information included in print data; detecting a specific location to be printed in a specific color based on the obtained color information in an image; and performing first color conversion to subject the color information included in the print data to color conversion processing in accordance with a color conversion instruction. A printing unit executes printing based on the print data executes the printing on the specific location by using a second color in accordance with a print instruction involving the specific color and the color conversion instruction, and executes the printing on a location other than the specific location by using a first color based on color information after the color conversion in performing first color conversion.