A Treatise on Painting
by Leonardo da Vinci, translated by John Francis Rigaud
The Cause of the Diminution of Colours
4015742A Treatise on Painting — The Cause of the Diminution of ColoursJohn Francis RigaudLeonardo da Vinci

Chap. CCLXXXV.The Cause of the Diminution of Colours.

The natural colour of any visible object will be diminished in proportion to the density of any other substance which interposes between that object and the eye.