| Fig. 11. |
Fig. 11. The distance of the spectator from the picture is of great importance; as the distortions and disproportions arising from too near a view are to be avoided, the object of drawing being to make things look natural; thus, the floor should look level, and not as if it were running up hill—the top of a table flat, and not on a slant, as if cups and what not, placed upon it, would fall off.
In this figure we have a geometrical or ground plan of two squares at different distances from the picture, which is represented by the line KK. The spectator is first at A, the corner of the near square Acd. If from A we draw a diagonal of that square and produce it to the line KK (which may represent the horizontal-line in the picture), where it intersects that line at A· marks the distance that the spectator is from the point of sight S. For it will be seen that line SA equals line SA·. In like manner, if the spectator is at B, his distance from the point S is also found on the horizon by means of the diagonal BB´, so that all lines or diagonals at 45° are drawn to the point of distance (see Rule 6).
Figs. 12 and 13. In these two figures the difference is shown between the effect of the short-distance point A· and the long-distance point B·; the first, Acd, does not appear to lie so flat on the ground as the second square, Bef.
From this it will be seen how important it is to choose the
right point of distance: if we take it too near the point of sight, as in Fig. 12, the square looks unnatural and distorted. This, I may note, is a common fault with photographs taken with a wide-angle lens, which throws everything out of proportion, and will make the east end of a church or a cathedral appear higher than the steeple or tower; but as soon as we make our
line of distance sufficiently long, as at Fig. 13, objects take their right proportions and no distortion is noticeable.
| Fig. 12. | Fig. 13. |
In some books on perspective we are told to make the angle of vision 60°, so that the distance SD (Fig. 14) is to be rather less than the length or height of the picture, as at A. The French recommend an angle of 28°, and to make the distance about double the length of the picture, as at B (Fig. 15), which is far more agreeable. For we must remember that the distance-point is not only the point from which we are supposed to make our tracing on the vertical transparent plane, or a point transferred to the horizon to make our measurements by, but it is also the point in front of the canvas that we view the picture from, called the station-point. It is ridiculous, then, to have it so close that we must almost touch the canvas with our noses before we can see its perspective properly.
| Fig. 14. | Fig. 15. |