Derived shadow on steps and slopes, and light through apertures
Shadow darkens with distance and uneven ground; brightness scales with the number of apertures
Blue sheet continuing the studies of shadow and light. Leonardo states that a derived shadow takes the shape of its casting body only when the light source has a like shape, that a shadow is never uniformly dark where it falls on ground not equidistant from the light, and that a shadow grows darker the farther it is from its body. He relates the proportion of brightness to the number of apertures through which one light reaches a surface, illustrated with shadows thrown across an inclined plane and stair steps. Concentric circle rosettes are drawn at the upper left.
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The derived shadow's shape depends on the light's shape
The percussion of the derived shadow never takes the figure of its casting body unless the light has a like figure and the shadowy rays bordering the luminous rays are equal in length.
Shadow on uneven ground is not uniformly dark
A shadow shows uniform darkness where it is cut only where that place is equidistant from the light; its parts darken with distance and brighten where rays fall at more equal angles. A shadow shows darker the farther it is from its casting body.
Shadow c d uneven because its field varies in brightness
The shadow c d, cast by the body a b equidistant from it, does not appear equal in darkness because it lies on a field of various brightnesses.
Brightness is proportional to the number of apertures
The brightnesses of sites lit by one and the same light stand in proportion to the number of apertures through which it reaches them; and the splendour of a single light at equal distance grows with the number of apertures it penetrates.
Concentric circle rosettes
Three circular figures at the upper left are worked as concentric rosettes of overlapping circles, one a dense rose within a ring, another a circle crossed by inscribed arcs, the third a small trefoil pattern. No transcription accompanies them.