ONE or the most important effects of the quality of suppleness and pliability possessed by all the great pointing mediums from Van Eyck to Rubens was the freedom they allowed the artist in his drawing. Unhindered by the difficulties of working with an inadequate medium, his brush could flow as his mind and eye and knowledge directed. Without the distractions that are always caused by any technical limitations, he was free to give his entire attention to the expression of his ideas and the exercise of his abilities. The supreme examples of this ease of execution are to be seen in the great masters of the sixteenth and seventeenth centuries, when the understanding of the human form together with the skill to express it, reached their highest development fit the same time that the technical means for such expression had been perfected.
It might be of value to examine briefly certain aspects of the subject of drawing, especially those relating to the natural facts with which drawing, as an art, has to deal. For in order to master this art, the draughtsman must be possessed not only of skill, coupled with a sound knowledge, but he must also have an understanding of what drawing really means.
To begin with, he must take note of some of the elementary principles of the visual aspect of nature:
First, that an object in space presents three dimensions--height, breadth and depth.
Second, that the various properties of an object are modified by its position in space.
Third, that the movement of lines and planes towards a vanishing point constitutes linear perspective.
Fourth, that the gradation of colors and tones or values, in relation to distance, constitutes aerial perspective.
Fifth, that without the lights and shadows which modify its own colors, an object would make no appearance to the eye.