An image forming apparatus is provided. the apparatus comprises a sheet feeding unit to supply a plurality of types of sheets; an image forming unit to form an image on a sheet; a detection unit to detect an image formed on the sheet; and a controller that causes correction information for each sheet type to be saved in a storage, and under set conditions, causes a specified type of sheet to be supplied by the sheet feeding unit, causes a chart for gradation correction to be formed by the image forming unit, and causes the correction information to be generated based on image information for which the formed chart for gradation correction was detected by the detection unit, and saves the correction information in the storage.