Even though ticket prices continue to rise, millions of people flock to movie theaters world-wide week after week. There are over 37,000 movie screens in the United States alone.

There are several key elements of the current movie-watching experience.

The Film

It takes thousands of feet of film to make a movie. There are 16 frames on one foot of film, which passes through the projector at 24 frames per second.

Look at these calculations from howstuffworks:

Therfore, a long movie like the three-and-a-half hour Titanic from 1997, is approximately 18,900 feet of film. That's 3.58 miles of film for one movie.

Since it takes so much film to make one movie, the film is chopped up into a number of reels to make it portable. The reels are then loaded into cans and distributed to the theaters. The projectionist unloads the reels and splices them together, matching the ends together and tapes them, to build the movie.

A built movie can have a diameter of up to four feet.

Movie film also contains the soundtrack information. The soundtrack is encoded on the film and the projector has different readers that translate it. There are four types of soundtracks on the film:

The Projection System

Once the film reels are spliced together and the movie is built, there has to be a way to project the movie onto the screen. That's where the projector comes in.

The built film is carefully placed on a feedout platter, threaded through the projector and attached to a rewind platter. For a seasoned projectionist, the threading process can be done in about one minute. The movie is threaded before every show.

The film travels on a one-way path through the rollers and gears. Unlike using a VCR, the film cannot be rewound in the projector.

The film travels a long way from the feedout platter to the rewind platter. One single sprocket that is misaligned with the film can cause problems once the movie is started.

Projecting the small frame of film to the screen several hundred feet away, depending on auditorium size, takes a powerful and long-lasting light source. Xenon bulbs, made up of rare xenon gas, are the most commonly used lamps. They can provide bright illumination for 2,000 to 6,000. The bulb is so powerful that If the film snags and stops in front of it for even a second, it will burn a hole through it.

(Photos by Tina Hasko)