The art of sound pictures (1930)

2i6 THE ART OF SOUND PICTURES depends on the simple fact that a series of pictures shown in quick succession makes the person or object photographed look as though he were moving. Do you remember the old nickel-in-the-slot machines? You put in a nickel and turned the crank. Then you looked through the slot and saw a series of pictures flop down like a pack of cards in front of you. Despite the flicker and other crudities of the apparatus, there was a strong illusion of movement in the figures shown on the flopping cards. The chorus girl appeared to kick, the funny man slipped on his banana peel, and the lovers put their arms around each other and kissed. These were the first crude motion pictures. They consisted of perhaps a hundred still photographs taken in the following manner. If a kick were to be shown, the first picture would be taken of the girl standing with both feet on the ground. The second picture would show one foot turned and knee bent ready to lift the foot in the kicking motion. The next picture would be taken with the foot raised a few inches above the floor as the kick started. Successive pictures would then be taken with the leg farther and farther up, until the last of the series would show the girl with her foot and leg extended at the height of the kick. Then another series of pictures would be taken in the same way showing the return of the girl’s foot to the floor. When these pictures were put together and shown in rapid succession in the slot machines, the illusion of leg movement would be accurate. Here is the reason for this illusion. If you look hard at any object, and then close your eyes or drop a shutter between your eyes and the object, you continue to see that object for a fraction of a second after the eyelids have closed or the shutter