A Treatise on Painting, by Leonardo da Vinci
Senex and Taylor, London
Suppose A a light, [Tab. 1. Fig. 11.] B a Body directly illumined by it,E another Body out of the reach of A, and only receiving Light from B, which is supposed of a Red Colour: In this Case, the Light communicated from B being of the same Colour with the Body, will tinge with Red the Opposite Body E; so that if E were of a Red Colour before, its Redness will now be heighten'd, and render'd much more beautiful than that of B: but sup posing it to have been Yellow before, then will there result from the mixture of these two, a dubious Colour partaking both of the One and the Other.