"Color itself is a degree of darkness."
German polymath Johann Wolfgang von Goethe said that, and much else, in his publication Theory of Colors.
Brain pickings recently ran an appreciation of this Treatise, calling it "an absorbing account of the philosophy and artistic experience of color."
It was also part of the romantic rebellion against classicism -- Goethe was taking on boring clockworks-loving old Newton.
Here's a link to the Amazon page which will allow you to look inside Goethe's text if you're so inclined.