There is the idea that, when we look at things, it is the yellow light that helps us the most, that we are the most sensitive for. But our circadian rhythms, which are the rhythms that help us to wake and sleep and be alert and relaxed and so forth and so on, they are much more triggered by blue light.

We have to rethink the way we light our cities. We have to think again about light as a default solution. Why are all these motorways permanently lit? Is it really needed? Can we maybe be much more selective and create better environments that also benefit from darkness? Can we be more gentle with light?

By modulating the amount of blue in our environment, we can help people to relax, or to be alert; to fall asleep, or to stay awake.

Rogier van der Heide Quotes