Always amazed when I see a fresh discussion of Movie Film. I am almost tempted to do an FAQ on my web space.
1) 35mm Movie film comes with Bell and Howell perfs, BH1866 vs KS 1370 for "normal film" Not a big deal for still cameras. A bit of a problem if using still Film in a movie camera.
2) All this film uses Process ECN-II - All of the curent film has a "REM-JET" back which will destroy c-41 Chemistry. (black gunk everywhere) So it eaither has to be done at home or by a movie lab.
3) all has a orange mask, and can be printed on colour paper. All has lower contrast than still film.
4 Most movie labs don't have a still splicer. They can get away with overlapping 6 inches of film at each end. Only a few folks have he sort of splicer that a still lab uses (heat seal paper) since the processers often run at 100FT/ Minute or better, they need a good splice.
5) to get slides it must be printed on 2383 or the equivalent product from Agfa or Fuji. The movie printers can't change filtration fast enough to allow for anything other than all 5 feet being printed at one flter seting (called Timing for historic reasons in the movie biz)
6 ECN negative has always had fairly good stability, the print stock used to be iffy as the major customers destroy prints after 6 months.