A table, which records a relationship between image data of patches included in a chart, which are acquired by capturing the chart under a plurality of types of illumination light having different characteristics, and the characteristics, is held for each image capturing device capturing the chart, and for each chart print condition. Specifying information of an image capturing device used to estimate characteristics of illumination light and a print condition of a chart used to estimate the characteristics of the illumination light are input as estimation conditions. Image data of a chart captured by the image capturing device under the illumination light is input. The characteristics of the illumination light are estimated based on a table corresponding to the estimation conditions and the input image data.