1. An image processing apparatus comprising: a specific image detection unit detecting an area including at least a part of a specific image in an input image; a representative color calculation unit calculating a representative color of the specific image on the basis of pixels belonging to the area detected by the specific image detection unit; a first correction curve acquisition unit acquiring a first correction curve for gradation correction on the basis of brightness of the representative color; a second correction curve acquisition unit correcting the representative color by the first correction curve and acquiring a second correction curve for gradation correction for every element color on the basis of the gradation value for every element color constituting the representative color after correction; a first correction unit correcting the gradation values of pixels, which belong to a color gamut defining a dark portion, from among pixels constituting the input image by using the first correction curve; and a second correction unit correcting the gradation value for every element color in each pixel constituting the input image by using the second correction curve, wherein the second correction curve acquisition unit calculates a difference between the gradation value for every element color constituting the representative color after correction and a predetermined reference value, and generates the second correction curve for every element color in accordance with the calculated difference for every element color.