An apparatus forms a plurality of patterns using a plurality of colors as a second pattern, and a plurality of patterns using one of the plurality of colors as a second pattern. The apparatus obtains a first detection result indicating the pitch of each one of the plurality of patterns of the first pattern, and a second detection result indicating the pitch of each one of the plurality of patterns of the second pattern. The apparatus calculates a difference between the first detection result and the second detection result to obtain a difference value, and calculates a correction value using the second detection result and the difference value. The correction value is used to control an image forming apparatus to suppress color shifts in the images.