Image processing device and printing system

An image processing device which generates print data for a printing device by performing an image process on image data, the device comprising:

• a user interface that is used for a user to set contents of the image process;
• and
• a processor including:
• an image data inputting section that inputs the image data;
• a resolution converting section that converts the image data to resolution corresponding to the printing device;
• a color converting section that generates ink amount data based on the image data converted by the resolution converting section;
• and
• a print data generating section that generates the print data based on the ink amount data,
• wherein the resolution converting section includes
• a color inputting section that inputs a first color and a second color through the user interface in order to perform a spot color replacement in which the first color is replaced with the second color by the color converting section, and
• a thinning processing section that determines whether or not the print data includes a predetermined region including the first color, the thinning processing section performing a simple thinning process on the predetermined region by eliminating one of two adjacent pixel rows constituting the image data upon determining that the image data includes the predetermined region and that the resolution of the image data is to be converted from a first resolution to a second resolution lower than the first resolution, and performing a different thinning process from the simple thinning process on a region other than the predetermined region upon determining that the image data does not include the predetermined region.