OF THE ACCIDENTS OF COLOURING IN TREES.
The accidents of colour in the foliage of trees are 4. That is: shadow, light, lustre [reflected light] and transparency.
OF THE VISIBILITY OF THESE ACCIDENTS.
These accidents of colour in the foliage of trees become confused at a great distance and that which has most breadth [whether light or shade, &c.] will be most conspicuous.
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.