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Shutter
A two- or three-bladed rotating device used in a film projector to interrupt the light source while the film is being pulled down into the projector gate.
One blade masks the pull-down while the other blade causes an additional light interruption, increasing the flicker frequency to 48 cycles per second on 35mm film — a level that is not objectionable to the viewer at the recommended screen brightness of 16 foot lamberts (55 candelas per square metre).
The National Film and Sound Archive of Australia acknowledges Australia’s Aboriginal and Torres Strait Islander peoples as the Traditional Custodians of the land on which we work and live and gives respect to their Elders both past and present.