The present disclosure describes a method and apparatus that can be used to adjust for distorted ambient light readings caused by the ambient light sensor being located behind the display screen. The strategy of the disclosure relies, at least in part, on spectral decomposition of ambient light measurements into independent sources (e.g., red, green, and blue display components of an Organic Light Emitting Diode (“OLED”) display screen and ambient light). Following the spectral decomposition technique, a more accurate ambient light measurement can be obtained in some instances. This technique enables determinations such as ambient lux and correlated color temperature independent of the content displayed on the screen.