OF PAINTING.

Colours seen in shadow will display more or less of their natural
brilliancy in proportion as they are in fainter or deeper shadow.

But if these same colours are situated in a well-lighted place, they
will appear brighter in proportion as the light is more brilliant.

THE ADVERSARY.

The variety of colours in shadow must be as great as that of the
colours in the objects in that shadow.

THE ANSWER.

Colours seen in shadow will display less variety in proportion as
the shadows in which they lie are deeper. And evidence of this is to
be had by looking from an open space into the doorways of dark and
shadowy churches, where the pictures which are painted in various
colours all look of uniform darkness.

Hence at a considerable distance all the shadows of different
colours will appear of the same darkness.

It is the light side of an object in light and shade which shows the
true colour.

On the colours of the rainbow (287. 288).