How shadow varies when light is larger than or equal to a body
Two diagrams of luminous and opaque spheres; edges of bodies appear broken against a ray-striped dark ground.
The opening note observes that the straight edges of bodies appear broken where they end in a dark place streaked by the striking of luminous rays. Two diagrams treat the case of a luminous body larger than the opaque one and the case of a luminous body equal in size to it, each yielding shadow of various quality. The page belongs to Notebook C's sustained study of how illumination falls upon bodies.
On this page
Straight edges appear broken against a dark ground
The straight boundaries of a body seem broken where they terminate in a shadowed place that is streaked by the striking of luminous rays. The interruption is an effect of light crossing the dark region, not of the body's own outline.
Light source larger than the opaque body
The upper construction sets two large luminous spheres against a small opaque sphere, so that converging cones of light pass by it. The result is a shadow of several graded qualities where the light greatly exceeds the body.
Light source equal in size to the opaque body
The lower construction pairs a luminous body with an opaque body of equal size, tracing the cone of shade thrown behind it. Leonardo again marks the various qualities of shadow produced under this balance.