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Let's Go to the Movies: The Mechanics of Moving Images
Technology and Development
Origins of the Movies
Motion pictures don't move; they rely upon the effect of persistence of vision. This occurs when a series of sequential images is displayed, each image lasting only for a short time. The resulting effect is that of continuous motion. The persistence effect was known to the ancient Romans, and was described in 65 BC by poet and philosopher Titus Lucretius Carus.
Thaumatrope
Simple mechanical devices using persistence of vision may have been known to the Chinese as early as 200 BC. These devices were probably similar to the thaumatrope (1826), a disk with an image on each side, suspended by two strings. When the disk is spun on its strings, the images appear to merge.
Phenakistascope
The phenakistoscope (also called the fantascope) is a disk with a series of radial slots placed around its circumference. It was invented in 1834. Between each slot and the center of the disk was a picture, each slightly different from its neighbor. An observer standing before a mirror looked through a slot and spun the disk to see an apparently moving image. The daedalum, a slotted drum rotating on its axis, was also invented in 1834. Drawings showing successive phases of action, viewed through the slits as the drum or disk turned, were seen so quickly that the images merged in the mind to produce the sensation of motion.
The phenakistoscope (also called the fantascope) is a disk with a series of radial slots placed around its circumference. It was invented in 1834. Between each slot and the center of the disk was a picture, each slightly different from its neighbor. An observer standing before a mirror looked through a slot and spun the disk to see an apparently moving image. The daedalum, a slotted drum rotating on its axis, was also invented in 1834. Drawings showing successive phases of action, viewed through the slits as the drum or disk turned, were seen so quickly that the images merged in the mind to produce the sensation of motion.
The Zoetrope
Devices using the principle of the slit and series of visible images were popular in the early and mid-1800s, with projectors and other refinements appearing after 1860. The zoetrope appeared in 1864 (it was sold by Milton Bradley for $2.50). The show was short and these devices were regarded more as amusements than serious entertainment.



Prerequisites for the Movies
Movies required several key inventions to be commercially viable. These included a bright source of light for the projector, long lengths of photographic film to replace photographic plates, and reliable cameras.
Gaslight, the electric arc, and later the electric lamp provided the necessary illumination to permit viewing by large groups of people. George Eastman's introduction of flexible film in 1889 provided the second key invention. Now it was possible to include a complex story on a continuous reel of film. It was left to Thomas Edison and his assistant, William Dickson, to perfect the motion picture camera and the sprocketed film that is universally used today. Sprocketed film provides the precise control of film position needed to eliminate jerkiness and other undesired effects.

Muybridge
Leland Stanford unwittingly started a chain of events that contributed to the development of motion pictures. To settle a wager regarding the position of a trotting horse's legs, he sent for Eadweard Muybridge, a British photographer who had recently been accclaimed for his photographs of Yosemite. Although Muybridge initially considered the task impossible, he made history when he arranged 12 cameras alongside a race track. Each was fitted with a shutter working at a speed he claimed to be "less than the two-thousandth part of a second." Strings attached to electric switches were stretched across the track; the horse, rushing past, breasted the strings and broke them, one after the other; the shutters were released by an electromagnetic control, and a series of negatives made. Though the photographs were hardly more than silhouettes, they clearly showed that the feet of the horse were all off the ground at one phase of the gallop. Moreover, to the surprise of the world, the feet were bunched together under the belly. None of the horses photographed showed the "hobbyhorse attitude" - front legs stretched forward and hind legs backward -so traditional in painting. The photos were widely published in America and Europe. The Scientific American printed eighteen drawings from Muybridge's photographs on the first page of its October 19, 1878 issue. Readers were invited to paste the pictures on strips and to view them in the popular toy known as the zoetrope, a precursor of motion pictures. It was an open drum with slits in its side, mounted horizontally on a spindle so it could be twirled. Drawings showing successive phases of action placed inside the drum and viewed through the slits were seen one after the other, so quickly that the images merged in the mind to produce the illusion of motion. In 1880, using a similar technique with a device he named the zoogyroscope, or zoopraxiscope, Muybridge projected his pictures on a screen at the California School of Fine Arts, San Francisco." Motion pictures were born...

Cameras and Projectors
There actually is no motion whatever in a "motion picture." On a screen, each successive photograph stands still for about 1/24th of a second, but the eye is tricked into believing that the flow of movement is continuous. The effect has been known since ancient times, and was described by Roman poet and philosopher Titus Lucretius Carus in the first century BC.
Until the end of the 1920s most cameras were hand-cranked; the operator turned a handle on the side of the camera to expose the film. Two turns a second was average, but camera operators could turn the crank more slowly; this speeded up all the actors' movements when the film was shown. The result is the familiar jerky, frenzied action of the silent comedy. Improved small electric motors made the motion picture camera a more reliable and consistent instrument.
The first projectors were really magic lanterns fitted with a hand-cranked device to advance the film. Many used gaslight as a light source, but as electricity became common, projectionists began to use powerful electric arc lights. Movie film was equipped with sprocket holes almost from the beginning. The holes were devised by Edison's assistant, William Dickson. A rotating sprocket wheel engaged the holes to advance the film. The sprocket caused a lot of wear, and shows were often interrupted when the sprocket holes tore or film broke. Early films were made of nitrocellulose (Guncotton!) and could catch fire if the projector mechanism stopped turning the sprocket that moved the film or if the sprockets tore and the film motion halted. Non-flammable film made of cellulose acetate was invented in 1912. While it didn't catch fire easily, it would char and melt quite nicely if the film stopped moving.

The Mutoscope: Flip Cards on Steroids…..
Herman Casler, an American inventor, devised the Mutoscope in 1894. It contained a series of cards, each equipped with a photograph of a moving subject. Turning a crank caused the cards to flip and be exposed to a viewing window in sequence, causing the illusion of motion.
The Mutoscope was popular as a coin-operated entertainment device in arcades and sideshows of the time. Perhaps the most widely viewed show was "What the Butler Saw," a photo series of the lady of the house undressing, purportedly viewed through a keyhole by the butler. It was pretty tame by modern standards, but daring for its time. The Mutoscope wa

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