You say you want a revolution

The title of this piece echoes the opening line of the 1968 Lennon/McCartney song Revolution. The song was originally released as the B-Side of the Beatle’s 45 rpm single Hey Jude. 45 rpm records were introduced in 1949 by RCA Victor as a market response to Columbia Record’s 33⅓ rpm long-playing records, which went on sale in 1948. Both formats allowed for much longer play times than the previous 78 rpm standard. The maximum playing time for a 78 rpm 12” record side was about 3½ minutes.

Rotational speeds have been an issue for recorded media since Edison invented the phonograph in 1877. His original invention used cylinders as the recording and playback media, which allowed for constant rotational speed. The lateral-cut disc, AKA the record, was introduced about a decade later to play on gramophone devices. Early discs were recorded at speeds from 60 to 130 rpm as well as on an assortment of record sizes. The early playback devices had to allow the owner to adjust rotational speed or the music would sound wrong. The industry finally settled on the 78 rpm standard in 1925, almost 50 years after Edison’s original invention.

Motion pictures use the measure of frames-per-second (FPS). Today we use digital files but motion pictures dating from the 1890s to the early years of this century used rolled film. Rolled film incorporates thousands of still frames on strips of celluloid. The strips have holes along both edges for sprocket wheels that advance the film. The earliest movie cameras and projectors were hand-cranked. Early films were captured at rates from 16 to 24 FPS. The playback speed rarely matched these rates. Cue sheets were distributed to projectionists that advised them of the “correct” playback speed. The cue sheets generally suggested that movies be played faster by 2 to 3 FPS than the shooting rate. Projectionists could do whatever they or the theatre manager wanted. They might slow down some scenes and speed up others. Afternoon showings were generally played back slower than evening showings. Different projectionists used different speeds for all or part of a film. The introduction of talkies, motorized cameras and motorized projectors changed this. Talkies required fixed playback rates lest the sound be too high or too low pitched.

We continue to use thousands of still pictures in digital video played back at rates that fool our eyes and brains into seeing motion. Digital videos are shot at a variety of speeds. The two most common are 24 FPS used in movies and 29.97 FPS (often rounded to 30 FPS) used for TV and home video. The 29.97 FPS synchronizes well with the 60 Hz scan rate of traditional and most high definition TVs. Europe uses 25 FPS rates rather than 29.97 FPS because their TVs are designed for PAL which scans at 50 Hz.

Even these rates are changing. Peter Jackson, who is directing and producing The Hobbit (a two movie adaptation of J.R.R Tolkien’s book, part 1 is slated for release this coming Christmas) shot the movies at 48 FPS. I suspect this is because the movie will be available in 3D and he wants a full 24 FPS for each eye. James Cameron (Titanic and Avatar) is working on sequels to Avatar. I understand he is shooting them at 60 FPS.

It seems appropriate to end this piece with the Peter Seeger song, “Turn! Turn! Turn!”