Until the standardization of the projection speed of 24 frames per second (fps) for sound films between 1926 and 1930, silent films were shot at variable speeds (or "frame rates") anywhere from 12 to 26 fps, depending on the year and studio. "Standard silent film speed" is often said to be 16 fps as a result of the Lumière brothers' Cinematographé, but industry practice varied considerably; there was no actual standard. Cameramen of the era insisted that their cranking technique was exactly 16 fps, but modern examination of the films shows this to be in error, that they often cranked faster. Unless carefully shown at their intended speeds silent films can appear unnaturally fast. However, some scenes were intentionally undercranked during shooting to accelerate the action—particularly for comedies and action films.
Slow projection of a cellulose nitrate
base film carried a risk of fire, as each frame was exposed for a
longer time to the intense heat of the projection lamp; but there were
other reasons to project a film at a greater pace. Often projectionists
received general instructions from the distributors on the musical
director's cue sheet as to how fast particular reels or scenes should be
In rare instances, usually for larger productions, cue sheets
specifically for the projectionist provided a detailed guide to
presenting the film. Theaters also—to maximize profit—sometimes varied
projection speeds depending on the time of day or popularity of a film, and to fit a film into a prescribed time slot.