Wednesday, October 7, 2009
The “shadow marvels” that were once shown at the cinemas are also based on the above-mentioned principle. Shadows cast by moving figures on the screen appear to the viewer, who is equipped with differently tinted glasses, as objects in three dimensions. The illusion achieved by bi-colored stereoscopy. The shadow-casting object placed between the screen and two adjacent sources of light, red and green. This produces two partially superimposed colored shadows, which viewed through viewers matching in colors. The stereoscopic illusion thus produced is most amusing. Things seem to fly right your way; a giant spider creeps towards you; and you involuntarily creep towards you; and you involuntarily shudder or cry out. The apparatus required is extremely simple. Every time the object behind the screen moved towards the source of light, thus causing the shadow cast on the screen to grow larger, the viewer thinks the object to be moving from the screen towards him. Every thing the viewer thinks is moving towards him from the screen is actually moving, on the other side of the screen, in the opposite direction from the screen to the source of light. Thus, shadow marvel is a stereoscopic illusion, which makes us amuse and it shown at the cinemas.