Area information is obtained with respect to a specified color and nozzle position having color unevenness. Then, coordinate information indicating a nozzle position corresponding to the above area information is obtained in a printing head or nozzle array corresponding to an ink color relating to the specified color information. Next, the number of candidate correction values or candidate patches is obtained on the basis of nozzle coordinates obtained corresponding to the area, by referring to a table. In this table, for example, the number of candidate correction values is small at a nozzle position where an effect due to the variations of nozzle ejection characteristics such as a nozzle ejection volume is small and a change direction is constant, and the number of candidate correction values is large at a nozzle position where an effect due to variations of nozzle ejection characteristics is large.