Patent ID: 8390892

Claim:
A spot color printing color converting device comprising: an image data acquiring unit for acquiring image data in which the colors of pixels are represented by the gradation values of a first color coordinate system; a spot color list acquiring unit for acquiring a spot color list associating the gradation values of the first color coordinate system with the ink gradation values of a second color coordinate system specifying the gradation of ink colors for printing spot colors; a numerical value range acquiring unit for acquiring a numerical value range between a minimum value and a maximum value out of a plurality of gradation values of the first color coordinate system associated with the ink gradation values of the second color coordinate system in the spot color list; a spot color pixel determining unit for determining whether the gradation value of a pixel to be converted from the image data is within the numerical value range and for determining whether the gradation value of the pixel to be converted coincides with any one gradation value in the numerical value range when the gradation value is within the numerical value range; and a color converting unit for converting the gradation value of the pixel to be converted into the ink gradation value of the second color coordinate system associated in the spot color list when the gradation value of the pixel to be converted coincides with any one gradation value in the numerical value range.