XLVII.

COMMUNICATION, APPARENT.

588.

The communication of colours, real as well as apparent, corresponds, as may easily be seen, with their intermixture: we need not, therefore, repeat what has been already sufficiently entered into.

589.

Yet we may here point out more circumstantially the importance of an apparent communication which takes place by means of reflection. This phenomenon is well known, but still it is pregnant with inferences, and is of the greatest importance both to the investigator of nature and to the painter.

590.

Let a surface coloured with any one of the positive colours be placed in the sun, and let its reflection be thrown on other colourless objects. This reflection is a kind of subdued light, a half-light, a half-shadow, which, in a subdued state, reflects the colours in question.

591.

If this reflection acts on light surfaces, it is so far overpowered that we can scarcely perceive the colour which accompanies it; but if it acts on shadowed portions, a sort of magical union takes place with the σκιερῷ. Shadow is the proper element of colour, and in this case a subdued colour approaches it, lighting up, tinging, and enlivening it. And thus arises an appearance, as powerful as agreeable, which may render the most pleasing service to the painter who knows how to make use of it. These are the types of the so-called reflexes, which were only noticed late in the history of art, and which have been too seldom employed in their full variety.

592.

The schoolmen called these colours _colores notionales_ and _intentionales_, and the history of the doctrine of colours will generally show that the old inquirers already observed the phenomena well enough, and knew how to distinguish them properly, although the whole method of treating such subjects is very different from ours.