IT is a curious phenomenon that although children and savages give evidences of an elementary sense of form, and are of course conscious of the solidity of objects, they are not conscious of the signs which convey that sense of the solid to the eye and mind.
Whether the pre-Raphaelite painters were ignorant of these signs or purposely ignored them is not certain, but Leonardo da Vinci blames his contemporaries for their ignorance in this respect ; and we might conclude that he was amongst the first to discover the part played by light and shadow in producing this sense of the solid.
The elementary principles of chiaroscuro are now patent to all artistically cultivated minds, and my readers, I feel sure, understand them up to a point. The distinction between definite light and marked shadow is sufficiently obvious ; but that a painter's modelling is due almost entirely to the knowledge, and a capacity to use that knowledge, of tone relations, is not generally appreciated. Yet modelling is perfectly simple to understand when the main governing principles are grasped.
This should make the matter fairly clear.
Here we have objects, the surfaces of which are composed of a large number of planes or facets. We shall see that the facet parallel with the
source of light predominates, and that the others, in proportion as they recede from the source of light, are toned and shaded.