In an illumination system (10), comprising: a lamp assembly (14) with a plurality of lamps (12A, 12B, 12C) and associated lamp drivers (13 A, 13B, 13C); a common controller (15) for generating control signals (ξ1, ξ2, ξ3) for the lamp drivers (13A, 13B, 13C); a memory (18) containing a color table with color points; the color points of the color table are located in a two-dimensional plane corresponding to a ceiling of a color space. Perimeter color points (PC) are located on the borderline of said plane, in groups of equidistant color points, as measured in a perceptual uniform second color space. Equidistant spoke color points (SC) are located on constant hue lines (42) in said plane, constant hue line connecting one of said perimeter color points (PC) to a white point (W).