Data processing apparatus and data processing method for reducing an uneven color made up of two or more ink colors

A data processing method for forming an on a print medium by use of a data processing apparatus provided with a plurality of nozzles for ejecting inks of a plurality of different colors to eject the inks of the plurality of colors, on the basis of output values based on correction parameters for determining the output values of a plurality of components according to input values of color signals of image data representing the color of an image and composed of signals of a plurality of color elements, the data processing method comprising:

• a print control step of controlling the plurality of nozzles to eject the inks of the plurality of colors, as an image for a correction parameter determination for determining the correction parameters, not to print an image based at least in part on the input values where signal values of the plurality of color elements are not a maximum value or a minimum value among the possible values of the respective signals of the plurality of color elements, but to print on the print medium a plurality of images based on the input values where each of signal values of a plurality of color elements except one particular element is the maximum value and a signal value of the particular element is one of a plurality of different values between the maximum value and the minimum value in a case where each of the plurality of color elements is the particular element, a plurality of images based on the input values where each of signal values of a plurality of color elements except one particular element is the minimum value and a signal value of the particular element is one of the plurality of different values between the maximum value and the minimum value in a case where each of the plurality of color elements is the particular element, and a plurality of images based on the input values where, among signals of a plurality of color elements, a signal value of one particular element is the maximum value, a signal value of another particular element is the minimum value, and a signal value of another element is one of the plurality of different values between the maximum value and the minimum value in a case where each of the plurality of color elements is the particular element;
• obtaining step of obtaining color information based on the image for the correction parameter determination printed in the print control step;
• and
• a determination step of determining the correction parameters based on the color information obtained in the obtaining step.

A data processing apparatus for processing image data to be printed on a print medium by using a plurality of nozzles for ejecting inks of a plurality of different colors to eject the inks of the plurality of colors, on the basis of output values based on correction parameters for determining the output values of a plurality of components according to input values of color signals of image data representing the color of an image and composed of signals of RGB color elements, the data processing apparatus comprising:

• a print control unit configured to control the plurality of nozzles to eject the inks of the plurality of colors, as an image for a correction parameter determination for determining the correction parameters, not to print an image based on input values of signal values corresponding to grid points on a surface and inside a color cube composed of three axes which are R, G, and B axes, but to print on the print medium an image based on signal values corresponding to grid points between vertexes of the color cube on edges of the color cube, the image corresponding to grid points on the edges for all of the edges;
• an obtaining unit configured to obtain color information based on the image for the correction parameter determination printed by the print control unit;
• and
• a determination unit configured to determine the correction parameters based on the color information obtained by the obtaining unit.