An image processor includes a signal acquiring unit, a first converting unit, a signal specifying unit and a second converting unit. The signal acquiring unit acquires a signal in a color space having a perceptual property. The first converting unit converts the signal acquired by the signal acquiring unit into a first color signal in a color-mapping space having an equilightness-equihue plane. The signal specifying unit specifies a second color signal in the color-mapping color space corresponding to the first color signal, as a color-gamut mapping process. The second converting unit converts the second color signal specified by the signal specifying unit into a signal in a same color space as the color space to which the signal acquired by the signal acquiring unit belongs.