An image-processing system for printing an image based on original image data. The storing unit stores at least one look-up table in association with at least one printing condition. The at least one look-up table is used to convert a color value in original image data into a limited color value that limits a total quantity of ink to be used in printing. The detecting unit detects, as a printing condition, at least one of a type of color material and a type of recording medium which are used for printing operation. The converting unit converts the color value data into the limited color value by using a look-up table that is assigned with a printing condition corresponding to the detected printing condition.