Coloured Shadows and Relief Against a Light Ground
Green shadows and red lights by cross-reflection; snow at sunset; with a ray diagram
A text page of the Trattato della pittura (folio 75 recto) with a small pen diagram of rays set into the text. A chapter on the colours of shadows explains how, on a body of uniform colour, shadows may turn greenish and lights reddish because light from the east strikes the object while a differently coloured object in the west casts reflected rays back eastward, the two sets of rays crossing and fixing their colours on the surface. Leonardo records seeing red lights and bluish shadows on a white object, as on snowy mountains when the sun sets and the horizon glows fiery. A second chapter opens on why a shadowed body against a light, illuminated ground appears detached and remote, because curved bodies necessarily fall into shadow on the side away from the light. The diagram illustrates the crossing of reflected rays between two bodies and carries further labels not included in the transcription.
On this page
Coloured shadows from crossing reflected rays
On a body of uniform colour the shadows may appear greenish while the lights are reddish. This happens when light comes from the east upon the object while a differently coloured object in the west, lit by the same light, throws its reflected rays back eastward; the rays strike the part of the first object turned toward it, cross there, and remain fixed with their colours and splendour.
Red lights and blue shadows on snowy mountains at sunset
Leonardo notes that he has often seen red lights and bluish shadows upon a white object. This occurs in the snow-covered mountains when the sun sets and the horizon shows itself fiery.
A body on a light ground appears detached
When a shadowed body terminates against a ground of light, illuminated colour, it necessarily appears detached and remote from that ground, a device useful in painting. This happens because bodies of curved surface necessarily fall into shadow on the side opposite to where the luminous rays strike them, that place being deprived of such rays.
Diagram of reflected rays between two bodies
A small pen diagram is set into the running text near the middle of the page, with the prose wrapping around it. It shows a shaded object at the left and lines of rays converging toward a radiant sun-like mark at the right, illustrating how reflected rays travel and cross between two bodies. Short labels written around the figure supply further text not present in the transcription.