Before movies had synchronized soundtracks, they had no real standard framerate. Indeed, the framerate of silent movies could depend on the projectionist. This is why silent movie buffs talk about the number of reels or total print length, rather than length in minutes. The average speed of silent film was 16 frames per second, although the fact that cameras were hand cranked meant the actual speed could vary greatly, even within individual films. In some cases, even when the director released a recommended frame per second (fps) rate, exhibitors screened the films at a faster rate, to fit more screenings into a day.

With the coming of sound, it was discovered that 16fps was too slow for accurate sound recording and playback, so the speed was standardized to the current 24 fps. [[note]]TV systems in many countries outside the Americas and Japan scan at 25 fps, so films are sped up to the same speed to avoid juddering once per second.[[/note]]

When projected using modern equipment running at this standard sound speed, silent films usually appear to run faster than normal. Because people have become accustomed to seeing silent films run at this incorrect speed, fake silent film footage appearing in TV shows will probably be highly {{Undercrank}}ed (and DeliberatelyMonochrome, though that's another story).

The early assumption that ''all'' silent films were shot at 16 fps led to further complications. In practice, some films were shot at as few as 14 or as many as 26-30 fps. It is believed, for example, that Film/{{Metropolis}} was shot at around 20 fps, and there is still [[ much debate]] about its correct projection speed.

Today, the variation of the silent frame rate is better understood, and is carefully adjusted for modern restorations so that the action onscreen appears natural.

* In the score of ''Theatre/{{Godspell}}'', the final chorus of "All for the Best" is marked "Very fast (Silent movie tempo)".
* Creator/CharlieChaplin's ''Film/CityLights'' and ''Film/ModernTimes'', silent films made in the age of synchronized soundtracks and therefore projected at a fixed rate, have the action still clearly undercranked.
** This is because the technique was often employed deliberately by comedy directors, in order to make slapstick sequences (for example, chases) seem even more frantic.
* ''Film/BramStokersDracula'' has some scenes set in London that were actually shot with a silent movie camera at silent speed.
* Some of the flashback scenes in the TV version of ''Discworld/GoingPostal'' achieve this effect with a specially modified digital camera.
* In ''WebVideo/TheSpoonyExperiment''[=/=]''WebVideo/AtopTheFourthWall'' collaborative preview of The Warrior #3 and #4, the silent film segment is done in this manner.
* Creator/TheBBC's 1960s UsefulNotes/WorldWarI documentary series ''The Great War'' was one of (if not the) first to show silent footage at a more realistic speed. This had the incidental benefit of making the limited footage available go further, although it still had to be fleshed out with post-war reconstructions.
* Thames Television's documentary series ''Hollywood'' begins with a contrasty, blurred and scratchy clip of an old silent comedy, shown at the wrong speed and accompanied by a tinkly piano score. This is then followed by a good-quality version of the same clip, slowed down and accompanied by an orchestra. The contrast is dramatic.
* Creator/BobMonkhouse's 60s series ''Mad Movies'' consisted of silent comedy clips compiled by Monkhouse, who often explained the frame rate issue in his narration.

See FastForwardGag when this trope is applied in Talkies for comedic use.