17-09-2026, 04:10 PM
(This post was last modified: 17-09-2026, 04:11 PM by Mike Watterson.)
Film speed of 24 fps is alleged to be because of sound in 1927(?).
But why?
35mm was created by cutting 70mm stock in half and adopted by Lumière brothers. Eventually the US Government cancelled Edison's bogus patent.
Before sound the movie was shot as slow as possible to still give illusion, so 14 to 20 fps.
16 frames of 35mm for standard movie format is 12", so 24 frames is 24 x 1 2/16 = 18 IPS. But initial talkies used 33&1/3 versions of 78s, almost 16" and played from centre. This was for 11 minutes, or 1000 ft of 24 fps 35mm film.
The Jazz Singer in 1927 is often quoted as first "Talkie", though demos as early as 1900 and maybe 1923, they where short movies. The Jazz Singer was the first feature length and was still using sound on disk, though sound on film had been demonstrated years earlier.
It's more likely that the 24 fps is to do with a synchronous motor off AC mains to have a consistent speed or the disc and film would quickly go out of sync. However initially In sound-on-disc technology in the USA the 1920s, a record turntable is connected by a mechanical interlock to a specially modified film projector, allowing for synchronisation. Edit or repair of film was an issue!
Sound on film didn't need a mains-locked projection/camera motor or interlock with disc player.
Public showing in 1922 in Germany of sound on film.
Later film projectors showed each frame twice (rotating shutter?) to reduce flicker.
It's a pity HD wasn't progressive only and 72 or 96 fps at 1024, 1152 or 1280 lines. Having 4K at 24 fps is daft.
My theory is that sound and loads of theatres meant what ever had been chosen was fixed. Variable speed is problematic. They wanted as slow as possible to save film. Almost all was shot outdoors (indoor scenes created on 3 sided boxes on outdoor lots. So lamp flicker at 60 Hz wasn't an issue.
https://en.wikipedia.org/wiki/Sound_film
But why?
35mm was created by cutting 70mm stock in half and adopted by Lumière brothers. Eventually the US Government cancelled Edison's bogus patent.
Before sound the movie was shot as slow as possible to still give illusion, so 14 to 20 fps.
16 frames of 35mm for standard movie format is 12", so 24 frames is 24 x 1 2/16 = 18 IPS. But initial talkies used 33&1/3 versions of 78s, almost 16" and played from centre. This was for 11 minutes, or 1000 ft of 24 fps 35mm film.
The Jazz Singer in 1927 is often quoted as first "Talkie", though demos as early as 1900 and maybe 1923, they where short movies. The Jazz Singer was the first feature length and was still using sound on disk, though sound on film had been demonstrated years earlier.
It's more likely that the 24 fps is to do with a synchronous motor off AC mains to have a consistent speed or the disc and film would quickly go out of sync. However initially In sound-on-disc technology in the USA the 1920s, a record turntable is connected by a mechanical interlock to a specially modified film projector, allowing for synchronisation. Edit or repair of film was an issue!
Sound on film didn't need a mains-locked projection/camera motor or interlock with disc player.
Public showing in 1922 in Germany of sound on film.
Later film projectors showed each frame twice (rotating shutter?) to reduce flicker.
It's a pity HD wasn't progressive only and 72 or 96 fps at 1024, 1152 or 1280 lines. Having 4K at 24 fps is daft.
My theory is that sound and loads of theatres meant what ever had been chosen was fixed. Variable speed is problematic. They wanted as slow as possible to save film. Almost all was shot outdoors (indoor scenes created on 3 sided boxes on outdoor lots. So lamp flicker at 60 Hz wasn't an issue.
https://en.wikipedia.org/wiki/Sound_film
