An electronic reading device includes an adjustable RGBW front light and an ambient light sensor. Additionally, the electronic reading device includes circuitry configured to receive a signal corresponding to a brightness level from the ambient light sensor, receive a signal corresponding to a current screen color temperature, calculate a predetermined mixture of light based on at least one of the brightness level or the current screen color temperature, Wherein the calculation allows the current screen color temperature to remain the same regardless of the brightness level, and display the predetermined mixture of light via the adjustable RGBW front light.