A Treatise on Painting
by Leonardo da Vinci, translated by John Francis Rigaud
The apparent Variation of Colours, occasioned by the Contraste of the Ground upon which they are placed
4014111A Treatise on Painting — The apparent Variation of Colours, occasioned by the Contraste of the Ground upon which they are placedJohn Francis RigaudLeonardo da Vinci

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.