Creative Speculation

The consistency of the shadows was also evaluated by application of the vanishing point principle. The concept of "vanishing point" perspective is widely known with respect. To artists and applies to photography as well. (178) This concept simply means that parallel lines in object space are depicted as converging lines on the image which will eventually meet at a point. Because. the Sun's distance from Earth is so great that it may be considered infinitely distant, it follows that,, in any sunlit scene, lines from objects to their shadows arc parallel. When these parallel lines are pictured the corresponding lines on the picture converge at a point known as the vanishing point. A picture of parallel railroad tracks provides a good illustration; the tracks are seen to converge to a point at the horizon.

In the case of the railroad tracks, the vanishing point is in the picture. This may not always occur. If the lines are perpendicular to the camera axis (the line from the center of the lens to the center of the film), the images of the lines will not appear to converge at a point, on the picture. The vanishing point may then be considered to be at infinity. In other cases, where the parallel lines are not perpendicular to the camera axis, the vanishing point is either in the picture or some finite distance outside it.

When this is the case, the directional consistency of shadows may be tested by drawing lines from images of objects to the corresponding points on the images of their shadows, and then extending these lines (beyond the actual picture if necessary) to see if they are meet at one point. If the lines do meet at one point, they are parallel and therefore consistent. If they do not met at one point, they are not parallel and consequently are not consistent.

When this analysis was applied to the backyard prints by drawing lines from a part of the stairway, the butt of Oswald's pistol, the muzzle of the rifle, Oswald's nose, et cetera, to the corresponding points on the shadows cast by these objects, the lines all met at the vanishing point. (See figs. IV-34 and IV-35, JFK exhibits Nos. F-387 and F-388.) Accordingly, the shadows were determined to he directionally consistent. A vanishing point analysis on 133C(Stovall) also yielded consistent results.