Patent ID: 8488188

Claim:
A printer gradation correcting method, comprising the steps of: outputting a plurality of color patch images different in gradation on a recording medium by a printer based on image data of a plurality of color patch images; measuring a gradation of each of the plurality of outputted color patch images by a color measuring device so as to obtain a plurality of different gradation measurement values; and correcting a gradation characteristic of the printer based on the plurality of different gradation measurement values; wherein each of the plurality of color patch images includes a patch-shaped image having a uniform gradation of a predetermined gradation representative value different from other color patch images and gradation fluctuation added in the patch-shaped image, and the added gradation fluctuation includes high gradation components each having a gradation value higher than the predetermined gradation representative value and low gradation components each having a gradation value lower than the predetermined gradation representative value and is configured such that a total gradation value of the high gradation components and the low gradation components measured in a measurement region by the color measuring device becomes a predetermined value, and wherein when the gradation characteristic of the printer is corrected, the gradation value of at least one of the plurality of color patch images is determined based on the gradation representative value, the predetermined value of the total gradation value of the high gradation components and the low gradation components, and the gradation measurement value.