Chap. CCIX.—Of proper Back-grounds for Figures.
As we find by experience, that all bodies are surrounded by lights and shadows, I would have the painter to accommodate that part which is enlightened, so as to terminate upon something dark; and to manage the dark parts so that they may terminate on a light ground. This will be of great assistance in detaching and bringing out his figures[45].
Chap. CCX.—Of Back-grounds.
To give a great effect to figures, you must oppose to a light one a dark ground, and to a dark figure a light ground, contrasting white with black, and black with white. In general, all contraries give a particular force and brilliancy of effect by their opposition[46].
REFLEXES.
Chap. CCXI.—Of Objects placed on a light Ground, and why such a Practice is useful in Painting.
When a darkish body terminates upon a light ground, it will appear detached from that ground; because all opake bodies of a curved surface are not only dark on that side which receives no light, and consequently very different from the ground; but even that side of the curved surface which is enlightened, will not carry its principal light to the extremities, but have between the ground and the principal light a certain demi-tint, darker than either the ground or that light.