In sketching we have to draw things as they seem, not as we know them to be. The top of a bucket is a perfect circle; yet when we draw it, unless we look down upon it from a point exactly above its centre, we represent it by an oval. Similarly, when we look along a stretch of railway line we know that the lines are exactly parallel, but they seem to draw nearer to each other. The rails of a fence are of equal height, and have been put at equal distances apart, but as we look along the fence it seems as though further away the workman had used shorter posts, and had put them nearer together. If we can see through a railway tunnel, it looks as though the way out at the other end were smaller than the way in at this; but we know they are of the same size. The rules under which lines seem to draw together and spaces become smaller have been called the rules of perspective, and it is important that we should learn these rules. Luckily they are few and not difficult to understand, and we will learn them as we go along in drawing a few simple forms that shall include them. In Fig. 1 we have a box, its corner towards us. In the box itself the lines A B, C D, and E F would be the same distance from each other from end to end, and if they were made ever so long would never meet, but here in the drawing they meet at G. In the same way the lines A H, C E, and D F, which in the actual box are parallel or equi-distant and so draw no nearer to each other, meet in the drawing at I. In the drawing, as in reality, the lines E H, C A, and D B are parallel, and would never meet, however far we might lengthen them. The lines of the brass round the key-hole follow the same rules. Let this box illustrate another matter. We move it into a slightly different position, so that we almost lose sight of the end E C A H. This end, in the language of artists, is now said to be “fore-shortened.” The lines that draw nearer together are said to “vanish.” The point where they meet is their vanishing point.
Fig. 1.
Fig. 2.
Fig. 3.
We will give some further examples of the same rules of perspective applied to different forms. The young artist standing before a scene he is going to sketch should decide what point is opposite his eyes. It may be some place in a church wall or in a tree, or even in the sky. However, having fixed it, mark it also upon your paper, and then draw a horizontal line through it. (Fig. 3.)
In the scene we have selected we stand upon a hill and look at a farmhouse that stands upon another hill. The point opposite our eyes is the window A. It will be noticed that the lines above the eyes come down to the line of sight or horizontal line, B C. Those below rise to it. Lines that are parallel to each other, whether they are roof lines tiles, the tops or bottoms of windows, meet in the same point, so that if you get one of those lines right, it is easy to get all the others right by continuing them to the same point.