A Treatise on Painting

by da Vinci Leonardo

A small light will cast large and determined shadows upon the surrounding bodies. A large light, on the contrary, will cast small shadows on them, and they will be much confused in their termination. When a small but strong light is surrounded by a broad but weaker light, the latter will appear like a demi-tint to the other, as the sky round the sun. And the bodies which receive the light from the one, will serve as demi-tints to those which receive the light from the other.

Chap. CXCIII.—How to distribute the Light on Figures.

The lights are to be distributed according to the natural situation you mean your figures should occupy. If you suppose them in sunshine, the shades must be dark, the lights broad and extended, and the shadows of all the surrounding objects distinctly marked upon the ground. If seen in a gloomy day, there will be very little difference between the lights and shades, and no shadows at the feet. If the figures be represented within doors, the lights and shadows will again be distinctly divided, and produce shadows on the ground. But if you suppose a paper blind at the window, and the walls painted white, the effect will be the same as in a gloomy day, when the lights and shadows have little difference. If the figures are enlightened by the fire, the lights must be red and powerful, the shadows dark, and the shadows upon the ground and upon the walls must be precise; observing that they spread wider as they go off from the body. If the figures be enlightened, partly by the sky and partly by the fire, that side which receives the light from the sky will be the brightest, and on the other side it will be reddish, somewhat of the colour of the fire. Above all, contrive, that your figures receive a broad light, and that from above; particularly in portraits, because the people we see in the street receive all the light from above; and it is curious to observe, that there is not a face ever so well known amongst your acquaintance, but would be recognised with difficulty, if it were enlightened from beneath.

Chap. CXCIV.—Of the Beauty of Faces.

You must not mark any muscles with hardness of line, but let the soft light glide upon them, and terminate imperceptibly in delightful shadows: from this will arise grace and beauty to the face.

Chap. CXCV.—How, in drawing a Face, to give it Grace, by the Management of Light and Shade.

A face placed in the dark part of a room, acquires great additional grace by means of light and shadow. The shadowed part of the face blends with the darkness of the ground, and the light part receives an increase of brightness from the open air, the shadows on this side becoming almost insensible; and from this augmentation of light and shadow, the face has much relief, and acquires great beauty.

Chap. CXCVI.—How to give Grace and Relief to Faces.

In streets running towards the west, when the sun is in the meridian, and the walls on each side so high that they cast no reflexions on that side of the bodies which is in shade, and the sky is not too bright, we find the most advantageous situation for giving relief and grace to figures, particularly to faces; because both sides of the face will participate of the shadows of the walls. The sides of the nose and the face towards the west, will be light, and the man whom we suppose placed at the entrance, and in the middle of the street, will see all the parts of that face, which are before him, perfectly illumined, while both sides of it, towards the walls, will be in shadow. What gives additional grace is, that these shades do not appear cutting, hard, or dry, but softly blended and lost in each other. The reason of it is, that the light which is spread all over in the air, strikes also the pavement of the street, and reflecting upon the shady part of the face, it tinges that slightly with the same hue: while the great light which comes from above being confined by the tops of houses, strikes on the face from different points, almost to the very beginning of the shadows under the projecting parts of the face. It diminishes by degrees the strength of them, increasing the light till it comes upon the chin, where it terminates, and loses itself, blending softly into the shades on all sides. For instance, if such light were A E, the line F E would give light even to the bottom of the nose. The line C F will give light only to the under lip; but the line A H would extend the shadow to all the under parts of the face, and under the chin.