An Organic Light Emitting Diode, OLED, display system, comprising: a) a display device including an array of light emitting pixels, each pixel having a plurality of OLEDs (44, 46 48) configured to emit different colors of light specifying a gamut and at least one additional OLED configured to emit a color of light within said specified gamut, wherein the brightness power efficiency of the additional OLED is higher than the brightness power efficiency of at least one of the plurality of OLEDs (44, 46, 48); b) means configured to generate a control signal indicating an amount of contribution to the light output of the display provided by the additional OLEDs, wherein the means for generating a control signal includes a current sensor and the control signal is proportional to the total current being drawn by the display device; and c) a display driver configured to: - receive a standard color image signal representing a relative luminance and color to be produced for each pixel of the display, and characterised in that to further, - generate a converted color image signal for driving the plurality of OLEDs (44, 46, 48) emitting different colors of light specifying the gamut in combination with the additional OLEDs emitting a color of light within said specified gamut in the display, the display driver being responsive to the control signal for applying an appropriate ratio of luminance to each of said plurality of OLEDs (44, 46, 48) and for controlling an amount of light produced by the additional OLEDs when displaying the converted color image signal even if the converted color image signal reduces color saturation of the display device so as to fulfil at least one of the following conditions: i) the power consumption of the display is decreased, ii) the rate of degradation of lifetime of the display device is decreased. a) a display device including an array of light emitting pixels, each pixel having a plurality of OLEDs (44, 46 48) configured to emit different colors of light specifying a gamut and at least one additional OLED configured to emit a color of light within said specified gamut, wherein the brightness power efficiency of the additional OLED is higher than the brightness power efficiency of at least one of the plurality of OLEDs (44, 46, 48); b) means configured to generate a control signal indicating an amount of contribution to the light output of the display provided by the additional OLEDs, wherein the means for generating a control signal includes a current sensor and the control signal is proportional to the total current being drawn by the display device; and c) a display driver configured to: - receive a standard color image signal representing a relative luminance and color to be produced for each pixel of the display, and characterised in that to further, - generate a converted color image signal for driving the plurality of OLEDs (44, 46, 48) emitting different colors of light specifying the gamut in combination with the additional OLEDs emitting a color of light within said specified gamut in the display, the display driver being responsive to the control signal for applying an appropriate ratio of luminance to each of said plurality of OLEDs (44, 46, 48) and for controlling an amount of light produced by the additional OLEDs when displaying the converted color image signal even if the converted color image signal reduces color saturation of the display device so as to fulfil at least one of the following conditions: i) the power consumption of the display is decreased, ii) the rate of degradation of lifetime of the display device is decreased. - receive a standard color image signal representing a relative luminance and color to be produced for each pixel of the display, and characterised in that to further, - generate a converted color image signal for driving the plurality of OLEDs (44, 46, 48) emitting different colors of light specifying the gamut in combination with the additional OLEDs emitting a color of light within said specified gamut in the display, the display driver being responsive to the control signal for applying an appropriate ratio of luminance to each of said plurality of OLEDs (44, 46, 48) and for controlling an amount of light produced by the additional OLEDs when displaying the converted color image signal even if the converted color image signal reduces color saturation of the display device so as to fulfil at least one of the following conditions: i) the power consumption of the display is decreased, ii) the rate of degradation of lifetime of the display device is decreased. i) the power consumption of the display is decreased, ii) the rate of degradation of lifetime of the display device is decreased.