After working on my school book style all these days, I just head to do some art theory.
I was checking on tones/values and other points of interest in different lights.
Like shown, the weaker the lightsource, the less contrast exists compared to the shadow.
Edges become softer, at least in the background, especially in a foggy scene of course, but as well in scenes with a depth effect. The range of value deffers as well, according to the light situation the range and saturation of colours diminishes with the intensity of light.