An obtaining unit obtains image data. An image processing unit performs, on the image data, image processing including gradation conversion processing according to an input/output characteristic defined by a gradation curve formed only of an exponential component represented by y=k·xn, where x is an input, y is an output, and k, n are coefficients. A calculating unit performs calculation for correction to improve lightness of dark area gradation of the image data. A correcting unit performs correction to improve lightness of the dark area gradation of the image data on which the image processing is performed by the image processing unit based on a calculation result of the calculating unit. Accordingly, image processing capable of generating a preferred image can be performed when various types of image processing are performed before and after compression of the dark area gradation.