A Treatise on Painting
by Leonardo da Vinci, translated by John Francis Rigaud
Observations on drawing Portraits
3995918A Treatise on Painting — Observations on drawing PortraitsJohn Francis RigaudLeonardo da Vinci

Chap. XXII.Observations on drawing Portraits.

The cartilage, which raises the nose in the middle of the face, varies in eight different ways. It is equally straight, equally concave, or equally convex, which is the first sort. Or, secondly, unequally straight, concave, or convex. Or, thirdly, straight in the upper part, and concave in the under. Or, fourthly, straight again in the upper part, and convex in those below. Or, fifthly, it may be concave and straight beneath. Or, sixthly, concave above, and convex below. Or, seventhly, it may be convex in the upper part, and straight in the lower. And in the eighth and last place, convex above, and concave beneath.

The uniting of the nose with the brows is in two ways, either it is straight or concave. The forehead has three different forms. It is straight, concave, or round. The first is divided into two parts, viz. it is either convex in the upper part, or in the lower, sometimes both; or else flat above and below.