A display method and display device are described having at least one sensor for detecting a property of light such as the intensity, color and/or color point of light emitted from at least one display area of a display device into a viewing angle of the display device and to measure and isolate the contributions of ambient light. An advantage of the sensor system is that it can be used for real-time measurements, e.g. while the display device is in use, and off-line, e.g. when the normal display functionality is interrupted, with a high signal to noise ratio and simultaneously can isolate the contributions of the signals from the backlight of the display device and the signals from the ambient light.