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.