Accelerated

The accelerated is a special effect , realized when shooting with a film camera , or postproduction with a shooting machine , and specific to the cinema , which consists in filming a moving subject by decreasing the rate of shooting (in English underkranking ) so that the movement of the subject is accelerated to the projection. In sound cinema, at standard projection rate, fixed at 24 frames or 25 framesper second, to accelerate twice the movement of the subject filmed, it is necessary that the camera which has taken the shooting rotates at 12 frames per second. For an accelerated three times, the camera should shoot at 8 frames per second.

The time-lapse (word composed from “time” and “lapse”, “lapse of time”) is an ultra-accelerated effect realized image by image over longer durations, characteristic technique of the animation, but also basic technique of photography . The English word time-lapse tends to supplant the accelerated French word, or redundant with it: “A beautiful time-lapse obtained by an accelerated”.

The opposite effect of accelerating is slowed down (in English overcranking ). The definition of the two special effects is based on their contradictory principle: the acceleration of the camera causes an idle motion in projection, slowing down the camera causes an accelerated movement in projection.

History

In 1896 , Louis Lumière sent operators around the world to bring back “animated photographic views”, as the Lyonnais brothers called their windings of impressed film. These reels are primarily for sale, especially to wealthy photography enthusiasts, but also to the fairground who bought a Cinematograph . To perform their mission, operators leave with an assistant because the amount of material carried is impressive. Not only do they take a camera with a tripod for shooting, but also 35 mm filmfeatures a patented round hole Light on each side of the photograms, and in addition, bottles of chemicals to ensure the development of the film. One of the difficulties is to find a dark place to introduce the reels of blank film into the camera store. The operation is always delicate, and the darkness is not often at the rendezvous, especially in sunny countries.

One of the operators, Francis Doublier , ” unintentionally invents the accelerated. He is in Spain March 7, 1897 , sent by Louis Lumière to film a Bullfight in Barcelona and he does not want to take the risk of missing an essential moment of the show, unable to reload his camera. He has the idea to slow the shooting rate of 16 frames to 9 frames per second to double his filming autonomy 1 . ”

While watching the reels, Francis Doublier notes with astonishment that the toreador’s passes are faster than in his memory. He understands that the 8 or 9 images that have recorded a second of real life, spend twice as fast on the screen when he cranks at the normal frame rate of 16 to 18 frames per second, based on the rhythm of a famous military march 2 An “error” that he will not commit any more and that no operator will try to do again, but this accelerated makes the passes of the toreadors particularly impressive.

In 1901 , a FS Armitage the idea of concentrating in less than two minutes the demolition and reconstruction of the Star Theater (New York) ( Demolishing and Building Up the Star Theater ). During the few weeks that this operation takes, the camera remains in the same place, well stalled, filming through the window of a building placed directly opposite. On the first day, the filmmaker takes a few seconds of normal traffic, carts, wagons, and crowds of pedestrians. Then, during eight hours each day (to avoid the low lights and the night), some animated images are taken every half hour.

A day goes on the screen in one to two seconds (at the rate of the dumb era: 16 frames per second), the shadows spin at high speed, pedestrians are activated like insects. The shop awning opens and closes at an infernal pace. The floors of the Star Theater disappear one after the other. When only heaps of stones remain, which are freed from the load, another piece of the film at normal speed shows the pedestrians, indifferent to the ruins, who go about their business. After shooting, FS Armitage had, like Georges Méliès in his special effects of the camera stop , clean the film of overexposed images recorded at each stop and restart of the camera 3, eliminating them with a clever scissors and welding the stumps with acetone (which the editors later wrongly named “collure”). This experience is the first time-lapse.

Accelerated scientific

Just as the scientific slowdowns made it possible to observe and analyze the course of extremely rapid physical phenomena, the accelerated, and especially the time-lapse, has been very useful for analyzing processes whose extreme slowness of execution does not lend itself to direct observation by the researcher. The first experiences of such shooting, which is more akin to photography than cinema itself, were carried out by physiologists, pioneers of “accelerated” photography, such as Jean Comandon 4 , Franck Percy Smith, or Dr. John Nash Ott Jr. , who have developed interval meters , adjustable add-ons for the camera, that automatically shoot at the desired pace.

Thus, the demonstration of the apparent displacement of the stars and stars by taking photograms one by one, spaced thirty or sixty minutes apart, and of a sufficiently long duration of exposure to record the faint lights, gives at the same time a fascinating spectacle but also allows to emphasize the relativity of these displacements with respect to our own double terrestrial rotation (on its axis and around the sun).

In the same way, accelerated on the germination and the development of the plants, gave to see natural phenomena which escaped in part to the human observation, for lack of time and patience.

Related Articles

  • Glossary of cinema
  • Slow motion
  • Interval

Notes and references

  1. ↑ Marie-France Briselance and Jean-Claude Morin , film grammar , Paris, New World ,, 588  p. ( ISBN  978-2-84736-458-3 ) , p.  51
  2. ↑ Robert Planquette, lyrics, Paul Cezano, music, “The Regiment of Sambre et Meuse” 1879. Turn the handle to the rhythm of the march was a recommendation that we could read the instruction manual of the Cinematograph.
  3. ↑ Briselance and Morin 2010 , p.  401
  4. ↑ ”  Jean Comandon (1877-1970)  ”  [ archive ] (accessed January 22, 2015 ) .

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