Editing 35 mm movie film (section)

===CS perforations===
In 1953, the introduction of [[CinemaScope]] by [[20th Century Fox#Twentieth Century/Fox merger|Fox Studios]] required the creation of a different shape of perforation which was nearly square and smaller to provide space for four magnetic sound stripes for stereophonic and surround sound.<ref name="hone" /> These perforations are commonly referred to as CinemaScope (CS) or "Fox hole" perfs. Their dimensions are {{convert|0.0780|in|mm}} in width by {{convert|0.0730|in|mm}} in height.<ref name="smpte102">{{cite book |title=ST 102:2002 - SMPTE Standard - For Motion-Picture Film (35-mm) — Perforated CS-1870 |date=26 July 2002 |doi=10.5594/SMPTE.ST102.2002|publisher=[[SMPTE]] |isbn=978-1-61482-304-9}}</ref> Due to the size difference, CS perfed film cannot be run through a projector with standard KS sprocket teeth, but KS prints ''can'' be run on sprockets with CS teeth. Shrunken film with KS prints that would normally be damaged in a projector with KS sprockets may sometimes be run far more gently through a projector with CS sprockets because of the smaller size of the teeth. Magnetic striped 35&nbsp;mm film became obsolete in the 1980s after the advent of [[Dolby Stereo]], as a result film with CS perfs is no longer manufactured.

During continuous contact printing, the raw stock and the negative are placed next to one another around the sprocket wheel of the printer. The negative, which is the closer of the two to the sprocket wheel (thus creating a slightly shorter path), must have a marginally shorter pitch between perforations (0.1866&nbsp;in pitch); the raw stock has a long pitch (0.1870&nbsp;in). While cellulose nitrate and cellulose diacetate stocks used to shrink during processing slightly enough to have this difference naturally occur, modern safety stocks do not shrink at the same rate, and therefore negative (and some intermediate) stocks are perforated at a pitch of 0.2% shorter than print stock.<ref name="case" />