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Projectors


Projectors

A film projector is an optic-mechanic device which is used to show movies, it project them in a screen. Most of the optic and mechanical components, except the concerning ones to illumination and sound, are also present in film cameras.

This device consists on a point of light whose rays are picked up by a curved mirror which throws them to a transparent film, at the same time they pass through an objective (lens) that increases the luminous pictures which are projected in the screen.

The projector has, the same as the photographic camera, two bobbins: a feeder that provides the film to the projector and another, the receiver that picks up the film once projected. It also has a mechanism that transforms the photographed sound in real noises.

The projector system in a modern motion picture theater has five main assemblies:
  • Optical sound head. - Reproduces optical sound (photographically recorded).
  • Projector head. - Projects the image onto the screen.
  • Lamphouse. - Furnishes the illumination for the picture.
  • Shutter and the platter system.- Feeds the film through the projector head.
  • Some projectors have a second sound head for the reproduction of magnetic sound (magnetically recorded).
Commercial projectors project the film to a speed of 24 pictures per second. Other projectors do it to 18 pictures. According to the film format, the projectors can be:
  • Super 8mm and 8mm (single-8) projectors
  • 16mm projectors
  • 35mm projectors