3 perf
Although this site expounds the virtues of the 2 perforation
pull down system, some camera owners or producers may prefer the 3 perforation pull down system.

Some of the advantages of the 3 perforation system are:

It saves 25% of camera footage.

It is more suitable for HDTV and cinema wide screen (1.85:1) formats *.

It exposes more of the 35mm frame, resulting in better resolution **.

* When your camera is modified for SUPER 35 the aspect ratio
of 3 perf is almost exactly 1.78:1 (HD TV) and very close to 1.85:1
(cinema wide screen.)

** Using the 3 perf system and a SUPER 35 combination
you expose the largest negative area possible for wide screen
projection, with negligible cropping or waste.
AND, you still get the 25% film saving.

Ratio: 2.35:1 Area: 207 sq mm.
Linear film saving: 50%
Ideal ‘scope’ format
Ratio: 1.56:1 Area: 310 sq mm.
1.85 area: 260 sq mm
Linear film saving: 25%
Ratio:1.76:1 Area: 464 sq mm.
1.85 area: 335 sq mm
Linear film saving: 25%
Ideal 1.85 and HD TV
Ratio: 1.37:1 Area: 352 sq mm.
1.85 area: 260 sq mm
Linear film saving: NIL