using the color sensors a second wavelength of light is emitted from the a light emitter and the color of light emitted by the light emitter is measured using the color sensors the shift in color space based on the measurements is calculated at least one calibration matrix based on the shift in colors space is calculated application_number US 94420607 A description a simplified version of a color illumination system 100 is shown in fig1 the illumination system 100 of fig1 includes a plurality of light emitters 106 which are described herein as being light emitting diodes leds 106 it is noted that emitters other than leds may be used in the illumination system 100 it is also noted that the term light emitter means a single source of light and not a combination of light sources a combination of light sources refers to the illumination system 100 the leds 106 are referred to individually as the red led 108 the green led 110 and the blue led 112 the color designations of the leds 106 refer to the general color appearance of the leds 106 which corresponds to the peak wavelength of light emitted by the leds 106 however colors other than the above described colors may be emitted by the leds 106 located proximate the leds 106 are a plurality of color sensors 116 the sensors may be located in area where the emission from the light emitters is well mixed the color sensors 116 are referred to individually as a red sensor 118 a green sensor 120 and a blue sensor 122 each of the sensors 116 detects a band of light or a bandwidth of wavelengths emitted by the corresponding leds 106 for example.