To a projector, what s important is not the actual image on the film but instead the sprockets which line the side because the projector uses these sprockets to pull the film through itself. The film is threaded through the film with the sprockets aligning themselves to a series of spring loaded rollers which provided needed tension to keep the film from slipping. Film does not roll through a projector continuously, rather it advances one frame at a time. Projectors use either a claw or intermittent sprocket to perform this task. Once the film makes it to the lens, it gets its image to the screen thanks to the powerful light of Xenon bulbs.
Xenon is a gas that provides amazing illumination for prolonged periods of time.
The bulb sits in the middle of the lamphouse which could also be know as The House of Mirrors because of the mirrors inside which help to focus the bulb s light. This light rockets out of the lamphouse to the shutter. This is a small plate that spins around 24 times a second. It lets the light get to the film, rotating in such a way to eliminate jerky movement and flickering on screen. The light must also get past the aperture, this is a small frame that makes sure the light only hits those areas of the film that should be seen on screen.