1. A method for generating black to maximize a gamut of a printing device, the method comprising: receiving a set of input parameters that define (i) achromatic curves to control an addition of black and setting of an achromatic gray value in an achromatic region of the gamut and (ii) chromatic curves that control an addition of black and setting of a chromatic gray value in the chromatic region, wherein the addition of black and setting of the gray value in the achromatic region is controlled separately from the addition of black and setting of the gray value in the chromatic region; for a given input value in a color space, identifying an achromatic value and a chromatic value; determining an output value for the input value by interpolating the output value from the achromatic value, the chromatic value, the achromatic curves and the chromatic curves.