Chap. CCLX.—A Precept relating to Painting.
Where the shadows terminate upon the lights, observe well what parts of them are lighter than the others, and where they are more or less softened and blended; but above all remember, that young people have no sharp shadings: their flesh is transparent, something like what we observe when we put our hand between the sun and eyes; it appears reddish, and of a transparent brightness. If you wish to know what kind of shadow will suit the flesh colour you are painting, place one of your fingers close to your picture, so as to cast a shadow upon it, and according as you wish it either lighter or darker, put it nearer or farther from it, and imitate it.