The advent of artificial light has extended our days and enabled more indoor lifestyles. Incandescent lights that were
ubiquitous in the 20th century are being phased out due to their inefficiency, but it turns out their energy-efficient
replacements are less healthy for our photobiology and are exacerbating disruption to our circadian systems.

This white paper is part 2 of 3, exploring the most common lighting technologies and the attributes that together
determine the quality of artificial light — color temperature and accuracy, spectral power distribution and blue light
content, brightness, and flicker. It also investigates the juxtaposition of energy efficiency mandates versus humancentric
lighting needs, and standards for determining circadian illuminance in the smart home.