Most film frame formats waste a large portion of the available film stock. This is built into the history of 35mm film, which began as a 4×3 (1.33) silent (no soundtrack) frame, known as SILENT APERTURE. With the advent of sound, the 1.33 area was retained but shrunk, wasting nearly 25% of the available negative while the camera continued to consume the full 4-perf volume of stock (this is known as ACADEMY APERTURE).
Then, with the advent of widescreen formats in the mid-fifties, 1.85 became a popular frame. This was achieved by once again cutting away more image area, this time chopping the top and bottom off the 1.33 frame within Academy Aperture. The frame was now so reduced that the entire image area would fit within 3-perfs of film stock instead of 4-perfs, but this savings was little used until recent years, because films were generally contact printed, rather than going through an optical printing process, or now a digital intermediate, so there was no stage at which to get the 3-perf image onto a 4-perf print (all the projectors remain 4-perf). Often the 3-perf image would be cropped even more to gain a widescreen 2.39 frame, which would otherwise only be available via the use of anamorphic lenses
In the mid-sixties, Technicolor created TechniScope, a 2-perf 2.35 format that could be printed directly to 4-perf using their proprietary dye-transfer printing technology. The format died off after the company did away with this printing technique, but has been resurrected with the advent of electronic post-production techniques.
So what are the real differences in these film frames? Here is a basic chart describing the available image areas. Note that the 4-perf image areas are for the Academy Aperture with its soundtrack as opposed to any non-standard Silent Aperture-based frame.
|4-perf Academy||Super35 3-perf||Super35 2-perf||Super16|
It costs approximately $40/min for 2-perf 35mm film to be purchased, developed and transferred to video dailies, while the same process for Super16 costs about $25/min. Depending on the final frame, however, the negative area can be two to three times as large in 2-perf as in Super16. For a 2.35 frame, the image area between 3-perf and 2-perf is a modest 21% drop with a 33% film stock savings.
This image, courtesy of Aaton, shows (from left to right) a comparison of 4-perf, 3-perf and 2-perf camera negatives. The 2-perf format achieves a 2.35 aspect ratio while using half the film of anamorphic 4-perf production.