Storage of the cellulose-nitrate film reels in theaters involves a lot of individual steel boxes “with tight-fitting covers” as Meloy surprisingly describes in Theatres and Picture Houses. The book was published in 1916, but still the lack of ventilation provided for the decomposing cellulose-nitrate base is a bit alarming. Primarily the choice of steel is for fire prevention and it also has a secondary function of obstructing any beams of light from reaching the film.