1. A method for operating a LED lighting system at a target output color, the LED system having three or more LED emitters emitting light of different colors combined into a light output, each LED emitter being operable at a controllable emitter drive setting, the LED lighting system further comprising a color sensor, the method comprising the steps of: a) providing calibration data comprising values for the light output of said LED lighting system for a plurality of values of the emitter drive settings of said emitters, and further providing at least one calibration matrix defining a relationship between measurements obtained from the color sensor of the LED lighting system and represented by sensor color point coordinates, and absolute color point coordinates in an absolute color space; b) operating the LED emitters at emitter drive settings selected in view of the target output color and based on the calibration data; c) measuring the sensor color point coordinates of the light output using the color sensor; d) determining the absolute color point coordinates of the light output based on the sensor color point coordinates measured at step c) and the at least one calibration matrix; e) comparing the absolute color point coordinates determined at step d) to target color point coordinates representing said target color to determine if a predetermined matching condition is met, and, if not, repeating steps c) to e) using different operation drive settings.