On Perspective: the eye and images on a wall
Why perspective drawn on a flat wall is false unless the eye corrects it
Headed 'De prospectiva' (On Perspective), the page sets out perspective constructions in lettered diagrams and explains how the eye sees pictures placed on a wall. Leonardo argues that a viewer always positions the eye in the middle of the pictures, so perspective drawn on a straight, rectilinear wall is false unless the eye's position corrects it by showing the wall foreshortened. Columns of figuring fill the lower half of the sheet.
On this page
Why images on a flat wall read as false
A demonstration of how the eye sees things, and why bodies made by such rules should not be placed on walls that recede. Because the eye viewing pictures on a wall always sits in the middle of them, perspective made on a rectilinear wall is false unless the eye's position corrects it by showing the wall foreshortened.
Left perspective diagram, points b, a, d, n, c
A lettered construction at the upper left carries the points b, a, d, n, c. It lays out the projection lines used to demonstrate the perspective argument.
Right perspective diagram, points v n, S t, p, q, o, r, o m
A second lettered figure at the right is marked v n, S t, p, q, o, r, o m. It shows circles and cones projected down toward a base line.
Columns of figuring
The lower half carries columns of calculation, among them 750, 375, 1000 and 1500 with divisions such as 1000 into 125 and 3000 into 428 4/8. They work out the proportional measures behind the perspective scheme.