Came across this snipet re: X-rays.

[Robert Hughes]

I believe that Super35mm and 3-perf are different formats: S35 uses the full 4 perf frame, as did old silent movies before the industry adopted the smaller Academy format (which left room for a soundtrack); 3-perf is Academy width, but only 3 perf height.

[vinny]

I believe that Super35mm and 3-perf are different formats: S35 uses the full 4 perf frame, as did old silent movies before the industry adopted the smaller Academy format (which left room for a soundtrack); 3-perf is Academy width, but only 3 perf height.

My bad. Yes, you are right, Robert.

[C. D. Keth]

I believe that Super35mm and 3-perf are different formats: S35 uses the full 4 perf frame, as did old silent movies before the industry adopted the smaller Academy format (which left room for a soundtrack); 3-perf is Academy width, but only 3 perf height.

Mostly right. The two can exist at once. 3-perf indicates how many perfs there are per frame. 3-perf is used for cropping to 1.85 or to 2.35 while using less film than traditional academy frame. Super 35 indicates that the frame uses the area on the film that used to be reserved for soundtrack, so it indicates the width of the frame.