↑Kawin, Bruce F. How Movies Work. New York: Macmillan Publishing Company, 1987, pp. 46-47. According to this reference, a full 1000-foot reel of film in the silent era had a maximum running time of 15 minutes. Silent-film speeds varied, but they were usually projected at 16 frames per second, much slower than the 24 frames of later sound films. Also, most reels, especially the final reels in multiple-reel releases, were not filled to their maximum capacities.
