The projection room can get quite hot due to the lamps and equipment; not surprisingly, there are several examples of theater fires that started when fire prevention of the most common sense was ignored. Talbot dramatically explains, “the heat concentrated upon the film by the converging rays of light from the condenser is tremendous. The effect is identical with that produced by focusing the sun’s rays with a lens upon a piece of paper. If the rays are permitted to play upon one part of the celluloid film for four or five seconds it will become ignited.” In fact, projection rooms were designed to be fire-rated in response; if a fire were to start, shutters can be closed over the opening through which the pictures are projected and the fire is contained to that space which is constructed of fireproof material like brick or concrete. Additional provisions would include a ventilating tube or flue extending up through the roof to expel any flames, smoke, or gases; this tube would be equipped with an electrical fan that is kept spinning at all times of operation. The film has a low survival rate, but the public’s safety is of greater importance. Also, because the theater has ample ventilation systems in place, both for the equipment and the comfort of patrons, smoke and gases are easily drawn out of the building were there to be a fire.

 

Another issue in the projection room is the accumulation of dirt and dust from the theater space, which if allowed to settle on the film, will scratch and ruin it unless directed away from the booth. To resolve this issue and the heat problem, there is a separate exhaust system going to each projection machine that removes heated air from the lamps and supplies cooler, fresher air. Humidity impacts the pliability of the film at all stages, and is perhaps most critical after the images are developed and the film is being shown in theaters. Controlling humidity levels ensures the film will not become brittle or break while being handled during printing/copying or projection.