Colored Shadows and the First Degree of Window Light
Each derived shadow takes the tint of its origin; the fullest light where the whole window is seen
Leonardo traces how each derived shadow is tinted by the color of the source it springs from: the shadow e f from n, h e from o, v h from p, and the triangle z k y from q. He then identifies f g as the first degree of light, because there the whole window a d illuminates the body, giving the opaque body m e a similar brightness. A large diagram at the page's center shows a lit sphere with graded internal bands and radiating shadow triangles fanning to the base line.
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Each derived shadow tinted by the color of its origin
The origin of shadow e f is n, tinted in its color; the origin of h e is o, likewise tinted; the color of v h takes the color of p because it is born from it, and the shadow of the triangle z k y takes the color of q because it derives from q. Each shaded zone thus carries the hue of the region of light or shadow that produced it.
The first degree of light where the whole window is seen
f g is the first degree of light, because there the whole window a d illuminates the body, and on the opaque body the zone m e is of similar brightness; z k y is a triangle. This marks the brightest band of illumination, from which the graded tones descend toward full shadow.
Diagram of a graded sphere with fanning shadow triangles
A horizontal line at top bears the labels D C B A (with G), representing the window. A sphere below is banded into graded zones marked m, n, o, t, q, and from it long shaded triangles radiate to the base line lettered E, H, X, V, T, S, R, mapping the grades of light and colored shadow.