Presentation by Dr. med. Alexander Wunsch, held at the 1st Health Optimisation Summit in London on September 15th, 2019. Duration: 42 min. Abstract: Light is a resource that should be subject to the same quality requirements as air, water and food: only the best is good enough. The developments of the last 10 years have led to the fact that in most environments only inferior artificial light (= LED) is present. In the realm of self-optimization, there is great potential for a healthier life if effective light hygiene and photonic diet are applied and if it is precisely controlled which light sources may influence the organism in which dosages. Not only the brightness and spectral composition of artificial light sources should be carefully examined, but also the temporal patterns in which the lighting environment influences us. Since much information in our natural environment is coded by colors, they can be understood as the quintessence of light – the paramount stimulus for health. In order to utilize the full potential of light, it is essential to study and master the manifold therapeutic and diagnostic benefits of color.