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Encyclopedia > Film perforations

Film perforations, also known as perfs, are the holes placed in the film stock during manufacturing and used for transporting (via sprockets and claws) and steadying (via pin registration) the film. Films may have different types of perforations depending on film gauge, film format, and the intended usage. Perforations are also used as a standard measuring reference within certain camera systems to refer to the size of the frame. Some formats are in fact referred to as (perforations per frame/gauge size) to give an easy way of denoting this. For instance, VistaVision is also known as (8/35), while standard 70 mm film is (5/70) as compared to IMAX, which is (15/70). This system does not indicate whether or not the film transport is horizontal or vertical, but there are currently no horizontal systems using the same number of perforations on the same gauge as a vertical one. Film stock is the term for photographic film on which films are recorded. ... This article does not cite its references or sources. ... A registration pin is a device intended to hold a piece of film, paper or other material in place during photographic exposure, copying or drawing. ... Film is a term that encompasses individual motion pictures, the field of film as an art form, and the motion picture industry. ... Film gauge is a physical property of film stock which defines its size. ... // Movie film formats Amateur formats: 8 mm Single-8 Super 8 mm Polavision 9,5 mm film 17. ... A VistaVision 35 mm horizontal camera film frame. ... 70 mm film (or 65 mm film) is a high-resolution film stock, of superior quality to standard 35 mm motion picture film format. ... IMAX theatre at the Melbourne Museum complex, Australia BFI London IMAX by night IMAX dome in Guayaquil, Ecuador IMAX (for Image Maximum) is a film format created by Canadas IMAX Corporation that has the capacity to display images of far greater size and resolution than conventional film display systems. ...

Contents

Pitch

One of the characteristics of perforations is their "pitch". This is the measurement of the distance between the top of two perforations in sequence. For 35 mm film and 16 mm film, there are two different pitches - short pitch (camera negative film) and long pitch (print stock, optical printers, bi-pack). For 35 mm these are 0.1866" and 0.1870"; for 16 mm they are 0.2994" and 0.3000". 35 mm film frames. ... 16 mm film was introduced by Eastman Kodak in 1923 as an inexpensive amateur alternative to the conventional 35 mm film format. ...


Shapes

BH/N

Additionally, in 35 mm and 65/70 mm there are several different shapes for these perforations. BH (Bell and Howell) or N perforations are used in camera negative film and have straight top and bottom with outward curving sides and have been in use since the very beginning of the 20th century. The BH perforation's dimensions are 0.110" (2.79 mm) from the middle of the side curve to opposite top corner by 0.073" (1.85 mm) in height.[1] The corners used to be sharp, but were slightly rounded in 1989 by 0.005" (.13 mm) to give them greater strength. The BH1866 perforation, or BH perforation with a pitch of 0.1866", is the modern standard for negative and internegative films. Film perforations, also known as perfs, are the holes placed in the film stock during manufacturing and used for transporting (via sprockets and claws) and steadying (via pin registration) the film. ...


KS/P

KS (Kodak Standard) or P perforations were introduced in the 1920s to improve steadiness, registration, durability, and longevity and thus are used for intermediate and release prints as well as camera negatives which require it, such as high-speed filming, bluescreen, front projection, rear projection, or matte work. KS perfs are rectangular with rounded corners, and measure 0.0780" (1.981 mm) high by 0.1100" (2.794 mm) wide.[2] Eastman Kodak Company (NYSE: EK) is a large multinational public company producing photographic equipment. ... The bluescreen setup. ... Front Projection is an in-camera visual effects process for combining foreground performance with pre-filmed background footage. ... Rear projection was devised by Farciot Edouart in 1933 - at the time, he was working for Paramount Studios. ... Matte refers to the following: the surface surrounding a framed picture, between the picture itself and the frame; usually made from coloured card a surface with a non-glossy finish (also matt or mat) a filmmaking technique a smelted sulfide material in extractive metallurgy a form of the name Matthew...


The increased height also means that the image registration was considerably less accurate than BH perfs, which remains the standard for negatives.[3] The KS1870 perforation, or KS perforation with a pitch of 0.1870", is the modern standard for release prints. Film perforations, also known as perfs, are the holes placed in the film stock during manufacturing and used for transporting (via sprockets and claws) and steadying (via pin registration) the film. ...


Others

DH

The Dubray Howell (DH) perforation was first suggested in 1931 to replace both the BH and KS perfs with a single standard perforation which was a hybrid of the two in shape and size, being like KS a rectangle with rounded corners and a width of 0.1100" (2.79 mm), but with BH's height of 0.073" (1.85 mm).[4] This gave it longer projection life but also improved registration. One of its primary applications was usage in Technicolor's dye imbibition printing (dye transfer).[5] The DH perf never caught on, and Kodak's introduction of monopack Eastmancolor film in the 1950s reduced the demand for dye transfer,[3] although the DH perf persists in certain special application intermediate films to this day.[6] Logo celebrating Technicolors 90th Anniversary Technicolor is the trademark for a series of color film processes pioneered by Technicolor Motion Picture Corporation (a subsidiary of Technicolor, Inc. ...


CS

In 1953, the introduction of CinemaScope 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.[7] These perfs are commonly referred to as CinemaScope (CS) or "fox hole" perforations, or simply "Foxholes" (because all Cinemascope films were made by 20th Century Fox). Their dimensions are 0.073" (1.85 mm) in width by 0.078" (1.98 mm) in height.[1] 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. Though CS perfs have not been widely used since the late 1950s, Kodak still retains CS perfs as a special-order option on at least one type of print stock.[8] A Fox logo used to promote the CinemaScope process. ... Twentieth (20th) Century Fox Film Corporation (known from 1935 to 1985 as Twentieth Century-Fox Film Corporation) is one of the major American film studios. ...


16 mm

All 16 mm perforations are rectangles with rounded corners and are 0.0500" high by 0.078" wide. The tolerance for these perforation dimensions was reduced to 0.01 mm in 1989, which allowed 16 mm camera manufacturers to slightly enlarge their registration pins and thus improve image registration and steadiness tolerances to less than 1/750th of the image height of the 16 mm frame.


8 mm

Standard 8 mm film uses 16 mm film that is perforated twice as frequently (half the pitch of normal 16 mm) and then split down the middle after development. Super 8 uses slightly smaller perfs on film which is already 8 mm wide. Super 8 pitch is 0.1667" and perfs are 0.045" high by 0.036" wide. 8mm film is a motion picture film format in which the filmstrip is eight millimeters wide. ... Kodachrome 40 KMA464P Super 8 Catridge Super 8 mm film, also called Super 8 is a motion picture film format that was developed in the 1960s and released on the market in 1965 by Eastman Kodak as an improvement of the older 8mm home movie format, and the Cine 8...


Placement

All of the systems described above place the perforations down either one side (Standard and Super 8, Super 16) or both sides (35 mm and 65/70 mm). Standard 16 mm can be either (single or double perf); some older cameras require double perf, but most can handle either. Because most cameras can handle both and increased popularity of Super 16, most 16 mm stock manufactured today is single perf unless requested otherwise.


Some obsolete formats such as 9.5 mm film and some variants of 17.5 mm film used a single perforation in the middle of the frame line between each image. This is considered more of a liability however, since any sprocket or claw error will likely damage the center of the frame itself rather than the outer edges. Three frames of 9. ...


References

  1. ^ a b Case, Dominic. Motion Picture Film Processing. Boston: Focal Press, 1985.
  2. ^ ANSI/SMPTE 139-1996. SMPTE STANDARD for Motion-Picture Film (35mm) - Perforated KS. Society of Motion Picture and Television Engineers. White Plains, NY.
  3. ^ a b ScreenSound Australia, "Technical Glossary of Common Audiovisual Terms: Perforations". Retrieved August 11, 2006.
  4. ^ Hart, Douglas C. The Camera Assistant: A Complete Professional Handbook. Focal Press: Boston, 1996.
  5. ^ Gray, Peter. "Sprocket Holes". Retrieved August 11, 2006.
  6. ^ Eastman Kodak. "Kodak Vision Color Intermediate Film - Technical Data". Retrieved August 11, 2006.
  7. ^ Kodak Motion Picture Film (H1) (4th ed). Eastman Kodak Company. ISBN 0-87985-477-4
  8. ^ Eastman Kodak. "Sizes and Shapes". Retrieved August 11, 2006.

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