Projection booth

A projection booth is a room or enclosure for the machinery required for the display of movies on a reflective screen, located high on the back wall of the presentation space. It is common in a movie theater. Its purpose is to isolate the noise produced by opto-mechanical projectors from the audience and to provide proper ventilation, temperature conditioning, and air cleaning for the exposed film and the projection mechanism.

To maintain sound and air isolation the projection will be through sound-resistant windows into the theater space.

Historically, movie projectors prior to modern automation would include a bell, activated by centrifugal force when the supply reel reached an appropriate speed. Two projectors would be used, requiring that the projectionist switch between the "operating" and "ready" projectors when a cue mark was visible on the screen in the upper right corner. The bell alerted the projectionist (who had likely viewed the movie too many times to ensure alertness) that attention was required. While the projector mechanism noise might be suppressed by the audience, the bell could not. Since the noise of the alert bell was clearly distracting to the audience the projection booth became required in movie theater design.