methods and apparatus are provided for a backlit display with variable luminance and chrominance . the apparatus comprises i groups of leds of different colors and one or more sensors optically coupled to the leds . the combined light produced by the leds is directed to a transmissive liquid crystal display , preferably through a diffusing layer . the sensors monitor the output s i of each group of leds . s i for each group of leds is multiplied by a chrominance determining parameter k i to obtain k i * s i which is then compared to a commanded luminance signal l c to obtain l c − k i * s i , which difference is used to adjust the drive current to each group of leds to achieve l c with the desired chrominance set by k i . by changing k i and l c the chrominance and luminescence of the display may be varied and aging effects compensated .