Patent ID: 7646507

Claim:
A calibration system, comprising: an image formation unit that outputs a patch sheet having a plurality of patch patterns based on different gradation values for each color of color material that is used; a selection unit that receives an instruction to select a device from among a plurality of color measurement devices comprising a first color measurement device and a second color measurement device of a lower color measurement accuracy than that of said first color measurement device; a color measurement unit that receives color measurement result data for said patch sheet that is color-measured by said color measurement device selected by said selection instruction; a color measurement value determination unit that acquires color measurement values for each of said patch patterns on the basis of said received color measurement result data; and a color adjustment unit that determines, for each of said colors of the color material, color measurement values for all the possible gradation values on the basis of each of said acquired color measurement values and said gradation values of the respective patch patterns corresponding with each of said color measurement values, and generates color correction information of said image formation unit by comparing the determined color measurement values with predetermined standard values, wherein said output patch sheet is common irrespective of said color measurement device selected by said selection instruction; when said first color measurement device is selected by said selection instruction, said color adjustment unit represents said color measurement values determined for all the gradation values by means of information of a first color space that differs from the color space of said color material, and compares said color measurement values with said standard values in a three-dimensional space; and, when said second color measurement device is selected by said selection instruction, said color adjustment unit represents said color measurement values determined for all the gradation values by means of information of said first color space and information of a second color space that differs from the color space of said color material and said first color space, and compares said color measurement values with said standard values in a four-dimensional space; and wherein the first color space is L*a*b* and the second color space is any one of R, G or B.