Editing Frame rate (section)

===Sound film===
When [[sound film]] was introduced in 1926, variations in film speed were no longer tolerated, as the human ear is more sensitive than the eye to changes in frequency. Many theaters had shown silent films at 22 to 26&nbsp;FPS, which is why the industry chose 24&nbsp;FPS for sound film as a compromise.<ref name="geek">{{Citation |last=TWiT Netcast Network |title=How 24 FPS Became Standard |date=2017-03-30 |url=https://www.youtube.com/watch?v=UcjYqfMaeHU | archive-url=https://ghostarchive.org/varchive/youtube/20211104/UcjYqfMaeHU| archive-date=2021-11-04 | url-status=live|access-date=2017-03-31}}{{cbignore}}</ref> From 1927 to 1930, as various studios updated equipment, the rate of 24&nbsp;FPS became standard for 35&nbsp;mm sound film.<ref name="Read2000"/> At 24&nbsp;FPS, the film travels through the projector at a rate of {{convert|456|mm|in}} per second. This allowed simple two-blade shutters to give a projected series of images at 48 per second, satisfying Edison's recommendation. Many modern 35&nbsp;mm film projectors use three-blade shutters to give 72 images per second—each frame is flashed on screen three times.<ref name=Brownlow/>