The following sections treat of the artist's subject matter from two points of view; first, investigating how natural and artificial forms have arisen and developed, reviewing the principles of growth and construction, and, secondly, indicating how these forms can be understood visually and transcribed onto paper. This artistic activity may involve leaving out some unessentials in order to stress the essential. The essential in turn is sometimes further enhanced by exaggeration, simplification, or elaboration.
Because of all this, it is obviously necessary to have a correct understanding of an object before reproducing it. Even deeper understanding is needed if the work departs from the external form, in an abstract representation, than if it is done from a model present in the flesh or in previous sketches and studies.
To draw well we must be acquainted with the skeleton and surface anatomy of the human body and of animals, the principles of growth in plants, the methods of construction used in buildings, and the factors underlying the phenomena of landscape. Without this knowledge gross mistakes are inevitable. Even if we intend to draw what we see and feel rather than what we know, we need a basis of objective knowledge to give it significance. There is no need to cling helplessly and blindly to this knowledge, but without it we can never penetrate far into the nature of things.
The works of the old masters are full of distortions or alterations of form and shape, deviations from what the eye actually sees, but they are never biologically or structurally wrong. A beginner usually draws a movement incorrectly unless he has some idea of the anatomical structure of the body. It is not so much detailed information which is necessary as a comprehensive understanding of the biological or, in architecture, the structural, principles which constantly recur.
This knowledge enables the artist to put onto paper forms taken either from nature or from his imagination. Whether in the constructive or impressionist style, a figure drawing is always begun in a different way from a landscape. The following pages aim at providing the basic knowledge from which an individual style of drawing can be developed.