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Two carbon rods burned inside a housing to throw a fierce white beam. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

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Yes. It sits on the Movies & TV shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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Mondo Knows Facts

Carbon arc lamps lit early cinema screens

Two carbon rods burned inside a housing to throw a fierce white beam A carbon arc lamp strikes an arc between two rods, and the tips burn away slowly as it runs. Projectionists adjusted the gap by hand and changed rods between reels. Xenon lamps, cleaner and steadier, replaced arcs in cinemas from the 1950s. It sits in Mondo's movies & tv collection, one of 200 facts that each trace back to the reference below.

Where this comes from

Encyclopaedia Britannica

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Technology trivia

More facts like this

A platter holds the entire feature on one reelThe print is spliced into a single strand and fed from a turntable A Geneva mechanism stops the film between framesA rotating pin turns the sprocket a quarter turn, then releases it to rest Polarised glasses give each eye a separate imageTwo projectors send light polarised at right angles, so each lens blocks the other Cinema screen brightness is measured in foot-lambertsA meter aimed at a white screen reports how much light reaches the audience Dolby Atmos treats sounds as movable objectsThe mix stores a position for each sound rather than assigning it a speaker Cinerama joined three projectors into one pictureEach machine filled a third of a deep curved screen and the seams were blended

Tags: projection, cinema, history

Carbon arc lamps lit early cinema screens: the short answers

Where does this come from, and can I check it?: Two carbon rods burned inside a housing to throw a fierce white beam. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a movies & tv fact?: Yes. It sits on the Movies & TV shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.