The whole value of art rests in the artist's ability to see well into what is before him. The model will serve equally for a Rembrandt drawing or for anybody's magazine cover. A genius is one who can see. Those who get their technique first, expecting sight to come to them later, get a technique of a very ready-made order. Fundamentally, light and shadows do not exist.
Every object presents a colour-mass, having different reflections on all sides.
Suppose a ray of sunshine should suddenly light up the objects in this open-air scene under grey light, you will then have what are called lights and shadows but they will be pure accidents. One thing I have learned, the absolute necessity for system in painting. Prepare your palette . But nature for us men is more depth than surface, whence the need to introduce into our light vibrations, represented by the reds and yellows, a sufficient amount of blueness to give the feel of air. I hope so.