An image forming apparatus is provided. The image forming apparatus includes: a storage configured to store a color conversion table; an image former configured to print a compensation chart corresponding to the color conversion table; a scanner configured to scan the printed compensation chart; and a changer configured to understand a range of brightness that the image former is able to represent using the scanned compensation chart, generate a gamma curve corresponding to the understood range of brightness, and change the color conversion table based on the generated gamma curve.