Increased levels of time are spent indoors, decreasing human interaction with nature and degrading photoentrainment, the synchronization of circadian rhythms with daylight variation. Recent research has shown that both the illuminance (i.e., perceived intensity) and wavelength of light affect photoentrainment and modern lighting technologies have improved our ability to construct lights with desired wavelengths. To improve photoentrainment in low light environments, the current research discusses a multiple regression model to explore the relationship between wavelength composition of artificial light and the circadian stimulus for a fixed illuminance.