A method of calibrating a lighting fixture (60, 110) comprising a plurality of light-emitting diodes of distinguishably different color coordinates, the method characterised in that it comprises: a first step of measuring separately and recording color coordinates (C ma (r, g, b, w)) of each of the plurality of light-emitting diodes, while each of the light-emitting diodes is operated at a specific pulse width modulation duty cycle; measuring and recording an operating temperature (T 0) along with the recorded color coordinates; inputting a desired target color set point (C T) and luminous flux (φ T) for the overall plurality of light emitting diodes; obtaining operating color coordinates (C 1) and luminous flux (φ 1) of each of the plurality of light emitting diode at a drive level duty cycle (d 1), wherein the operating color coordinates and luminous flux (φ 1) are obtained in order to produce essentially the desired target color set point (C T), using color coordinates (C ma (r, g, b, w)) measured and recorded at the first step and at least one of: an iterative method, a color shift measurement method and a direct measurement method; operating the lighting fixture (60, 110) at the obtained operating color coordinates (C 1) and luminous flux (φ 1) of each light emitting diode at the drive level duty cycle (d 1) and measuring overall color coordinates (C mT) and luminous flux (φ mT) of the overall plurality of light emitting diodes along with the temperature (T 0); determining if a distance between the measured color coordinates (C mT) and the operating color coordinates (C 1) is less than a predefined value; and if not, then computing a flux (φ c) based on the measured color coordinates (C mT) and measured luminous flux (φ mT) using color mixing; adjusting the operating luminous flux (φ 1) to this value and returning to the step of operating the lighting fixture (60, 110) but at this adjusted operating luminous flux (φ 1); and if so, then remeasuring the operating temperature (T 0) and recording the operating temperature with the operating color coordinates (C 1) and luminous flux (φ 1), original value or as previously adjusted; and estimating an operating luminous flux (φ n) for color points with a same color coordinate (C n) but different flux level by computation based on predetermined flux data curves for light emitting diodes. a first step of measuring separately and recording color coordinates (C ma (r, g, b, w)) of each of the plurality of light-emitting diodes, while each of the light-emitting diodes is operated at a specific pulse width modulation duty cycle; measuring and recording an operating temperature (T 0) along with the recorded color coordinates; inputting a desired target color set point (C T) and luminous flux (φ T) for the overall plurality of light emitting diodes; obtaining operating color coordinates (C 1) and luminous flux (φ 1) of each of the plurality of light emitting diode at a drive level duty cycle (d 1), wherein the operating color coordinates and luminous flux (φ 1) are obtained in order to produce essentially the desired target color set point (C T), using color coordinates (C ma (r, g, b, w)) measured and recorded at the first step and at least one of: an iterative method, a color shift measurement method and a direct measurement method; operating the lighting fixture (60, 110) at the obtained operating color coordinates (C 1) and luminous flux (φ 1) of each light emitting diode at the drive level duty cycle (d 1) and measuring overall color coordinates (C mT) and luminous flux (φ mT) of the overall plurality of light emitting diodes along with the temperature (T 0); determining if a distance between the measured color coordinates (C mT) and the operating color coordinates (C 1) is less than a predefined value; and if not, then computing a flux (φ c) based on the measured color coordinates (C mT) and measured luminous flux (φ mT) using color mixing; adjusting the operating luminous flux (φ 1) to this value and returning to the step of operating the lighting fixture (60, 110) but at this adjusted operating luminous flux (φ 1); and if so, then remeasuring the operating temperature (T 0) and recording the operating temperature with the operating color coordinates (C 1) and luminous flux (φ 1), original value or as previously adjusted; and estimating an operating luminous flux (φ n) for color points with a same color coordinate (C n) but different flux level by computation based on predetermined flux data curves for light emitting diodes.