Why your ceiling lights might be getting it all wrong.

It's basically timing, then intensity, then spectrum and spatial distribution — that's the importance of choosing where the light should come from. What I really wanted to emphasize is that the light needs to reach your eye, of course. But a lot of human-centric lighting applications are done from ceiling level. So either you need to significantly increase the amount of light coming from the ceiling, or you need to get your light from somewhere else — like a window.