You see, it is entirely a matter of how things look to the eyes. The painter, as I have said, does not represent the facts as he knows them to be, but the impressions which the facts make upon his eyesight; and these impressions, by the way in which he renders them, he hands on to us. His picture is not nature, but a suggestion or illusion of nature.
Now, although Giotto had discovered that, to make you feel that you could walk back through his pictures, he must represent the successive planes, he only partly found out how to do it. It was not until nearly a hundred years later that a painter named Masaccio learned how to fill the whole of his picture with a suggestion of atmosphere, so that the objects took their places properly in their proper planes, and it was still later before artists thoroughly worked out the methods of perspective.
The greatest difficulty that they had to surmount was how to “foreshorten” their figures, or represent them in “foreshortening.” A simple way of understanding what this means is to stand in front of a mirror and stretch out your arms to left and right, like the arms of a cross. Each extends a long way. But now bring them in front of you and stretch them toward the mirror. At once they look shorter, or at any rate you cannot see their length. They appear foreshortened. Or you may practice a still more “violent” example of foreshortening, if you are able to place the mirror where you can see your body, when lying down with the feet toward it, for now the whole length of the body appears foreshortened in the mirror. The surface of the latter, you observe, corresponds exactly with the surface of a picture. It is a flat plane upon which is produced the appearance of successive or receding planes, and though you cannot see the length of your body because it is foreshortened, you are made to feel its length.
It was a long time before artists overcame the difficulty of representing this effect; and the first pictures in which it was accomplished were naturally regarded as wonders. Since it is not the purpose of this book to teach you to draw I will mention only one of the principles involved. It is the one we have already been discussing—the contrast of light and dark, or, as it is called, “chiaroscuro.” Artists soon discovered that, if an object has bulk, that part of it which is nearest to the light will reflect most light; the parts less near, less light; while the parts that are exposed to no light will appear dark. As this was how the artists saw the objects, it was so they tried to represent them. They learned to “model” the object, that is to say, to represent it as having bulk, by reproducing in their pictures the contrasts of light and dark. At first the contrasts were crude, chiefly of the very light and very dark, but by degrees the artists became more skillful and learned to represent also all the varying gradations of less light and less dark. By this time they were better able to surmount the difficulty of foreshortening.
You will see how, if you will again stand in front of the mirror and stretch out one arm toward it. The simplest test is made, if you can arrange that the light shall be directly at your back, for then it is reflected by the mirror on to the front of you. In this case you will notice that your outstretched hand receives the most light, because it is nearest to the light. If it were represented in this way in a picture, our habit of seeing the highest or brightest light on the highest or most directly exposed surface of an object would make us feel that the hand projected in front of the body.
If, however, you stand before the mirror with light falling upon you from one side, the picture in the mirror will be quite different in appearance. The light and shadow will be more broken up and diversified. Some part of your hand, it may be simply the edges of the fingers, will catch a high light, even if it is not the highest; and light probably will fall on your forearm, between the wrist and elbow, and again upon the upper part of the arm. Broadly speaking, your arm presents three planes of form—the hand, the forearm, and the upper arm. And, though to your untrained eye the light on all of these planes may seem the same, to an artist’s eye it would vary according to the angle at which the light hits the plane, or, as the artist himself would say, according to the angle of the plane. These angles vary all over the figure, as you may be able to see if you examine your picture in the mirror. To mention a few, in a general way, there are several angles around each of the shoulders, about the breast, round the neck, while the face, with its projecting nose, its receding eye sockets, its rounded cheeks and so on, presents a regular patchwork of angles of plane. Or shall I say, the whole figure presents a whole multitude of facets like a cut diamond? Only, unlike the diamond, its facets are uneven in size and irregular in shape. And just as the light on the facets, here very light and elsewhere not so light, informs us of the shape of the diamond, so do these differently lighted angles of plane, when presented in a picture, give us the suggestion of the figure’s shape.
And now study the shadows in your mirror picture. They result from the opposite of what we have been talking about. In their case the angles of plane are turned away from instead of toward the light, and some parts, such as the hollows of the folds of your dress or coat, seem to catch no light at all and to be quite dark. I expect you find it much easier to detect the various gradations of dark or shadows than those of the light. And a great many artists, especially in olden times, seem to have seen the shadows more than the lights—for they represent the former with more subtlety, that is to say, with a keener eye for variations, than they do the latter. Indeed, the subtle rendering of light is particularly an accomplishment of modern artists.
Well, if you have carefully studied your portrait in the mirror, I think you must have discovered how large a part the contrast of light and shadow plays in the appearance of the figure, and therefore, what an equally important part it plays in producing an illusion of reality in the picture. I do not forget that an artist by simply drawing an outline with a pen or pencil can also suggest to us the appearance of an object. But, if he does so, it is by the help of ourselves, for he relies on our imagination to supply what he has omitted.
Finally, before we leave the mirror portrait, I should like to ask you in which of the following ways you see it: Do you see it as a bold, simple composition of light and dark? Or are you conscious of a hundred and one little details about the clothes and face and hair and so on? The former is what artists call the “broad” way of seeing nature. Many artists see nature in this way and represent in a bold, free, broad manner simply the big general facts. Others, on the other hand, as you may be, are conscious at once of the great variety of details of which the whole is composed, and represent the subject in a highly detailed manner. Neither is the right nor the wrong way. Thousands of fine pictures have been painted in both ways. On the other hand, if you find you grow to like one way more than another, it will be because you yourself, as well as the artist, have the habit of receiving impressions in that way. Do not on that account think other people wrong for receiving impressions differently and therefore preferring the other sort of picture. We cannot help having preferences, but they shouldn’t prejudice us against the preferences of others.