35mm Film Formats Explained
www.youtube.com/watch?v=Pema-zdPF2g - a 12 minute video from the In Depth Cine youtube channel.
The blurb: ‘By far the most popular film format is 35mm. But what you may not know is that there are then 3 further format choices that need to be made between: 2-perf, 3-perf or 4-perf. But what is a perf and how does it affect both the budget and how the footage looks?’
More here: www.indepthcine.com/videos/perf-35mm-film