For tunable white, LEDs with different light colors are mixed on a PCB so that they can be separately controlled. Depending on the characteristics of the LEDs, color temperature ranges from warm white (e.g. 2700K) to daylight white (e.g. 6500K) can be set.
To bring the achieved spectra even further towards lower or higher color temperatures, the white LEDs can be supplemented with red or blue LEDs.
An important criterion for the quality of a tunable white luminaire is uniformity of power output, luminous flux and color rendering in all the settings. To achieve this, the LEDs used as well as the control gear must be optimally matched and calibrated as far as possible. Both High-power LEDs and Mid-power LEDs are available for tunable white.