Funding for this site is provided by readers like you.
The Senses
Sub-Topics

Vision













Link : Michael Moore website

Link : MON ONCLE D'AMERIQUE
MOTION PICTURES: THE GRAND OPTICAL ILLUSION

What could be more routine than an action scene in a movie, or someone talking on TV? Often we forget that when we see images moving in these two media that are so central to our social lives, we are actually the victims of a motion illusion.

The moving images that you see when you go to the movies are not really caused by the continuous movement of anything in the images themselves. On the contrary, what you are really watching is a series of still photographs (or "frames") that are separated from each other by thin black strips. When the movie was being filmed, the movie camera shot several of these frames per second (in today's movie cameras, 24), so that the position of the people and objects that were moving differs slightly from one frame to the next. Television and video cameras work differently, but they are still capturing a succession of still images.

When a film is shown, to give the impression of fluid rather than jumpy motion, the projector cannot just run the film continuously. Instead, it must stop each frame between the projector lamp and the projector lens for a fraction of a second. In between frames, a shutter closes between the lamp and the film to darken the screen so that you cannot see the film moving from one frame to the next.

But if all you saw was 24 frames and 24 intervals of darkness per second, your eyes would still notice a bit of flicker from the alternating light and darkness. Starting at about 50 images per second, however, you stop noticing the darkness and begin perceiving the light as continuous. The shutter therefore closes not just once between frames, but also once while each frame remains in position. Thus, what you are actually seeing each second is 48 images alternating with 48 intervals of darkness.

It was long thought that the reason we stop perceiving flicker at around 50 images per second was a phenomenon called "retinal persistence". For decades, books about motion pictures also said that retinal persistence was responsible for the illusion of movement that we experience on the big screen. But now it would appear that the real explanation for these two phenomena is quite different.

The French physician and inventor Étienne-Jules Marey was the first person to use photographs taken in rapid succession to record the phases of locomotion in animals and humans. In 1877, the British/American photographer Eadweard James Muybridge took a series of 24 photos of a running horse, then mounted them on a device that projected them at a sufficient speed to create the illusion that the horse was galloping.

The first public screening of motion pictures took place on December 28, 1895 in Paris, using the Cinematograph projector invented by brothers Louis and Auguste Lumière. The screening consisted of a few short silent films shot by the Lumière brothers themselves, including Train Arriving at La Ciotat Station (see below).


Still from the film Train Arriving at La Ciotat Station,
by Louis Lumière (1895)

The period until the late 1920s was the era of silent films. There was no sound to accompany the images except, sometimes, a pianist playing music live while the movie was being shown. Sound entered the movies in 1927 when the film The Jazz Singer came out in the United States.

The date when colour was introduced into motion pictures is harder to pin down. The first great popular colour films were The Wizard of Oz and Gone With the Wind, both of which came out in 1939. But a silent film called Cupid Angling was shot in colour back in 1918, and various experiments with hand colouring were attempted prior to 1908.

Lastly, on January 27, 1926, the Scottish inventor John Baird gave the first public demonstration of his process for receiving images on a cathode-ray tube—the ancestor of television.

History : Du muet au sonore... History : 28 Décembre 1895 : première séance publique et payante. History : History of Motion Pictures Research : LES FRERES LUMIERE
Research : Georges Méliès imagine le 7e Art Research : John Logie Baird and Television Research : John Logie Baird History: Film History Before 1920

  Presentations | Credits | Contact | Copyleft