[s1mon]

“ While the illusion of motion works at 16 fps, it works better at higher frame rates. Thomas Edison, to whom we owe a lot of debt to for this whole operation (light bulbs, motion picture film, Direct Current, etc.) believed that the optimal frame rate was 46 frames per second. Anything lower than that resulted in discomfort and eventual exhaustion in audience. So Edison built a camera and film projection system that operated at at a high frame rate.

But with the slowness of film stocks and high cost of film, this was a non-starter. Economics dictated shooting closer to the threshold of the illusion, and most silent films were filmed around 16-18 frames per second (fps), then projected closer to 20-24 fps. This is why motion in those old silent films is so comical, the film is sped up.”

https://www.filmindependent.org/blog/hacking-film-24-frames-...

Another take on film speeds says that films were projected at a variety of speeds, depending on the original filming as well as the economics of fitting multiple showings into a schedule. https://web.archive.org/web/20110724032550/http://www.cinema...