On Painting: Universal Light and the Vision of the Owl
A precept on sparing ornament and using broad light for grace, with optical diagrams of the human and owl eye
Headed De pictura, the leaf opens with two precepts on painting: never load figures in your narrative pictures with so much ornament that it hides their form and attitude, and place figures in broad, universal light rather than small lights, for gentle overall light embraces the relief of bodies and reads with grace from afar while small lights drown the work in shadow. The rest of the page turns to optics, with marginal diagrams of the imprensiva (the perceptive faculty), the nocturnal pupil, and the eye of the owl. Leonardo argues that light seen with two eyes is twice as strong as with one, that the least light of night in great quantity equals a little strong daylight, and that the owl's pupil changes size more than any other creature's.
On this page
Grace comes from broad, universal light
Figures gain more grace in universal lights than in particular and small ones, for the great, gentle lights embrace the relief of bodies and appear with grace from afar. Works portrayed in small lights take on a great sum of shadow and, seen from a distance, look like flat tinted patches.
Ornament must not hide a figure's form and attitude
In your narrative pictures never give figures and other bodies so many ornaments that they impede the form and attitude of the figures and the essence of those bodies. The teaching keeps the outward figure legible beneath its decoration.
The human faculty, the nocturnal pupil, and the owl's eye
Marginal diagrams label a the perceptive faculty (imprensiva) for seeing luminous objects, and mark the nocturnal pupil and a the perceptive faculty of the owl. A further figure keys a the light of the sun, b the light of day, and c the nocturnal light that the owl receives.
Two eyes give twice the light of one; the owl's pupil changes most
Light seen with one eye is half as strong as with two: eye b lights the faculty a by one degree, and adding the second gives two degrees, double the first. The least light of night, in great quantity, equals a small strong quantity of daylight; and every pupil changes with the light, the owl's most of all.