Just to get
anal retentive, here are a few
amendments to
Leynos' writeup:
NTSC video actually runs at a frame rate of 29.97 frames per second. Therefore, during telecine (and, hence, to make 3:2 Pulldown actually work), the film passing through the telecine machine is slowed to a frame rate of 23.976 frames per second.
This causes a problem: to get a precise matchback to your negative after cutting a film project on video (i.e., in a digital non-linear editing system), you must edit at 24fps. Otherwise, your negative cutter has to sync up your video cut and the film negative in a lockbox and check the edits by eye...and they're gonna be slightly off.
Therefore, when digitizing telecined footage (if you want to cut at 24fps...not necessary for video-only release), the video must be sped up by 1%. Digital NLEs have a 'pulldown' function which provides this solution.