"Here's what I wanted to say about the white and the black [tones]. Let's take 'The Sower'. The painting is divided into two; one half is yellow, the top; the bottom is violet. Well, the white trousers [Van Gogh darked them later!] rest the eye and distract it just when the excessive simultaneous contrast of yellow and violet would annoy it. That's what I wanted to say."
January 1, 1970
https://en.wikiquote.org/wiki/Vincent_van_Gogh