But the difference is in the way the modern artist regards shadow. He has studied nature for the purpose of representing the actual effects of nature; and, in so doing, has discovered that the secret of all effects is due to the action of light. So he has learned to look at everything, shadows included, in its relation to light. A shadow to him, then, is not something different from light; it is a lessening of the light. Some of the light has been intercepted by the foliage of the tree, so that less light reaches the ground. It may be that very little light filters through the leaves. But, whether more or little, the spot from which the light has been intercepted, still contains some light. Even what we usually call the shadows have light in them.