the base f g is equal to the base r f. At thepoint d the pyramid of light is narrower than the pyramid of shadow by so much as the base s f is less than the base f g.
Divide the foregoing proposition into two diagrams, one with the pyramids of light and shadow, the other with the pyramids of light
[only].
261.
Among shadows of equal depth those which are nearest to the eye will look least deep.
262.
The more brilliant the light given by a luminous body, the deeper will the shadows be cast by the objects it illuminates. V.
Theory of colours.
Leonardo's theory of colours is even more intimately connected with his principles of light and shade than his Perspective of Disap-
pearance and is in fact merely an appendix or supplement to those principles, as we gather from the titles to sections 264, 267_, and
276, while others again_ (Nos. 281, 282_) are headed_ Prospettiva.
A very few of these chapters are to be found in the oldest copies and editions of the Treatise on Painting, and although the material they afford is but meager and the connection between them but slight, we must still attribute to them a special theoretical value as well as practical utility--all the more so because our knowledge of the theory and use of colours at the time of the Renaissance is still extremely limited.
The reciprocal effects of colours on objects placed opposite each other (263-272).
263.
OF PAINTING.
The hue of an illuminated object is affected by that of the luminous body.
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264.
OF SHADOW.
The surface of any opaque body is affected by the colour of surrounding objects.
265.
A shadow is always affected by the colour of the surface on which it is cast.
266.
An image produced in a mirror is affected by the colour of the mirror.
267.
OF LIGHT AND SHADE.
Every portion of the surface of a body is varied [in hue] by the [reflected] colour of the object that may be opposite to it. EXAMPLE.
If you place a spherical body between various objects that is to say with [direct] sunlight on one side of it, and on the other a wall illuminated by the sun, which wall may be green or of any other colour, while the surface on which it is placed may be red, and the two lateral sides are in shadow, you will see that the natural colour of that body will assume something of the hue reflected from those objects. The strongest will be [given by] the luminous body; the second by the illuminated wall, the third by the shadows. There will still be a portion which will take a tint from the colour of the edges.
268.
The surface of every opaque body is affected by the colour of the objects surrounding it. But this effect will be strong or weak in
proportion as those objects are more or less remote and more or less strongly [coloured].
269.
OF PAINTING.
The surface of every opaque body assumes the hues reflected from surrounding objects.
The surface of an opaque body assumes the hues of surrounding objects more strongly in proportion as the rays that form the im-
ages of those objects strike the surface at more equal angles.
And the surface of an opaque body assumes a stronger hue from the surrounding objects in proportion as that surface is whiter and
the colour of the object brighter or more highly illuminated.
270.
OF THE RAYS WHICH CONVEY THROUGH THE AIR THE IMAGES OF OBJECTS.
All the minutest parts of the image intersect each other without interfering with each other. To prove this let r be one of the sides of the hole, opposite to which let s be the eye which sees the lower end o of the line n o. The other extremity cannot transmit its image to the eye s as it has to strike the end r and it is the same with regard to m at the middle of the line. The case is the same with the upper extremity n and the eye u. And if the end n is red the eye u on that side of the holes will not see the green colour of o,
but only the red of n according to the 7th of this where it is said: Every form projects images from itself by the shortest line, which
necessarily is a straight line, &c.
[Footnote: 13. This probably refers to the diagram given under No. 66.]
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271.
OF PAINTING.
The surface of a body assumes in some degree the hue of those around it. The colours of illuminated objects are reflected from the surfaces of one to the other in various spots, according to the various positions of those objects. Let o be a blue object in full light, facing all by itself the space b c on the white sphere a b e d e f, and it will give it a blue tinge, m is a yellow body reflected onto the space a b at the same time as o the blue body, and they give it a green colour (by the 2nd [proposition] of this which shows that blue and yellow make a beautiful green &c.) And the rest will be set forth in the Book on Painting. In that Book it will be shown, that, by transmitting the images of objects and the colours of bodies illuminated by sunlight through a small round perforation and into a dark chamber onto a plane surface, which itself is quite white, &c.
But every thing will be upside down.
Combination of different colours in cast shadows.
272.
That which casts the shadow does not face it, because the shadows are produced by the light which causes and surrounds the shadows. The shadow caused by the light e, which is yellow, has a blue tinge, because the shadow of the body a is cast upon the pavement at b, where the blue light falls; and the shadow produced by the light d, which is blue, will be yellow at c, because the yellow light falls there and the surrounding background to these shadows b c will, besides its natural colour, assume a hue compounded of yellow and blue, because it is lighted by the yellow light and by the blue light both at once.
Shadows of various colours, as affected by the lights falling on them. That light which causes the shadow does not face it.
[Footnote: In the original diagram we find in the circle e "giallo" (yellow) and the cirle d "azurro" (blue) and also under the circle of
shadow to the left "giallo" is written and under that to the right "azurro".
In the second diagram where four circles are placed in a row we find written, beginning at the left hand, "giallo" (yellow), "azurro"
(blue),
