Phasmatrope
For fifty years after the invention of photography in the mid-1800s, this new technology was confined to still images. But over this interval a number of scientists strove to present a more realistic view of human activity in motion pictures. True success would only come with the invention of Eastman’s perforated flexible film and Edison’s intermittent projector.
Prior to that time many machines were devised to present the illusion of continuous motion by showing the viewer a succession of separate still images. Perhaps the earliest version was the phasmatrope; it certainly was the first in which the illusion of motion could be seen simultaneously by a large audience. The performance was seen briefly by hundreds of people at the Centennial Exhibition at Philadelphia in 1876.
Recently, I re-created this machine under the guidance of Stephen Berkman, a prominent scholar of early photographic history. The heart of the instrument is a large metal disk carrying 16 images cut from 35mm film and taped over 16 rectangular apertures. Each image is precisely located relative to a slot and semicircular arc machined in the rim of the disk. The disk is moved intermittently to hold each image briefly in the beam of a projection lamp. The 16 film images show successive positions of a moving human figure. An electric motor turns a disk and pin that engage the rim of the large wheel, moving and stopping it about 5 times/second.
The original phasmatrope was turned by a hand crank and projected the images with light from a kerosene lamp. Our re-creation uses electricity to position the images and to power the light bulb. Of course, motion pictures today are much brighter and smoother, as electric arc lamps show images at 16 to 24 frames/second.
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