Light from Above; Where to Stand to View a Painting
Cast shadows, high lighting for figures, and a diagram of the best viewing position for a glossy picture
A text leaf from Part Three of the Treatise on Painting, carrying a small pen diagram. It advises that cast shadows grow broader with distance, that a figure lit partly by fire and partly by daylight should favour the air's light with a near-red firelight, and above all that painted figures take their light from high, since people in the street are lit from above and a face lit from below is hard to recognize. A chapter with a lettered diagram then locates where a viewer should stand before a glossy oil or varnished picture to avoid reflected glare, and a further chapter sets the vanishing point at a man's eye-height.
On this page
Give painted figures a high, broad light
Cast shadows on walls or ground should be well defined and grow ampler the further they fall from the body; a figure lit by both fire and daylight should let the air's light dominate, with the firelight near-red. Above all, painted figures should be lit largely and from on high, since people in the streets are lit from above and even a close acquaintance is hard to know when lit from below.
Diagram: where to stand before a glossy painting
A small pen sketch marks the painting as the line b–a with the light source d and viewing positions c and e. The text explains that a glossy oil or varnished picture behaves almost like a mirror: standing between c and e, and nearest to c, one sees worst because the window's rays leap back there, whereas standing between e and d, nearest d, the sight works best, that place sharing least in the reflected glare.
Setting the point at eye height
A closing chapter begins the rule that the point (the vanishing point) should be placed at the height of the eye of an ordinary man.