...which are often of various colors, which corrupt the nearest images when the bodies are small; but it does not fail that a small color near at hand tinges a reflection more than a large color far off, by the sixth [proposition] of perspective, which says: Large things may be at so great a distance that they will appear far smaller than small things close by.

[163] Where reflections are most perceptible.

That reflection will be of readier evidence which is seen against a field of greater darkness, and that will be less perceptible which is seen against a lighter field; and this arises because, of things of various darkness placed in contrast, the less dark makes the darker one appear murkier, and of things of various whiteness placed in contrast, the whiter makes the other appear less white than it is.

[164] Of double and triple reflections.

Double reflections are of greater power than simple reflections, and the shadows that come between the incident light and these reflections are of little darkness.

Let a be the luminous body, b c the direct [light]; and let n s o be the lit parts of the bodies; n p m and d h e the parts of these bodies lit by reflections; the reflection d h e is the simple reflection; n p m is the double reflection. The simple reflection is that which is seen from a single lit body, and the double is seen from two lit bodies; and the simple d h e is made by the lit body b a; the double n p m is composed from the lit body b r and from the lit body d r e; and its shadow is of little darkness, which comes between the incident light n and the reflected light n p.