Chap. CCLXVIII.—Of Back-grounds suitable both to Shadows and Lights.
The shadows or lights which surround figures, or any other objects, will help the more to detach them the more they differ from the objects; that is, if a dark colour does not terminate upon another dark colour, but upon a very different one; as white, or partaking of white, but lowered, and approximated to the dark shade.
Chap. CCLXIX.—The apparent Variation of Colours, occasioned by the Contraste of the Ground upon which they are placed.
No colour appears uniform and equal in all its parts unless it terminate on a ground of the same colour. This is very apparent when a black terminates on a white ground, where the contraste of colour gives more strength and richness to the extremities than to the middle.
CONTRASTE, HARMONY, AND REFLEXES, IN REGARD TO COLOURS.
Chap. CCLXX.—Gradation in Painting.
What is fine is not always beautiful and good: I address this to such painters as are so attached to the beauty of colours, that they regret being obliged to give them almost imperceptible shadows, not considering the beautiful relief which figures acquire by a proper gradation and strength of shadows. Such persons may be compared to those speakers who in conversation make use of many fine words without meaning, which altogether scarcely form one good sentence.
Chap. CCLXXI.—How to assort Colours in such a Manner as that they may add Beauty to each other.
If you mean that the proximity of one colour should give beauty to another that terminates near it, observe the rays of the sun in the composition of the rainbow, the colours of which are generated by the falling rain, when each drop in its descent takes every colour of that bow, as is demonstrated in its place [65].