Edge numbers are a series of numbers with key lettering printed along the edge of a 35 mm negative at intervals of one foot and on a 16 mm negative at intervals of six inches. The numbers are placed on the negative at the time of manufacturing by one of two methods: The edge numbers serve a number of purposes. Every key frame is numbered with a multi-digit identifier that may be referred to later. In addition, a date of manufacturing is imprinted, then the type of emulsion and the batch number. This information is transferred from the negative to the positive prints. The print may be edited and handled while the original negative remains safely untouched. When the film editing is complete, the edge numbers on the final cut film correspond back to their identical frames on the original negative so that a conform edit can be made of the original negative to match the work print. Laboratories can also imprint their own edge numbers on the processed film negative or print to identify the film for their own means. This is normally done in yellow ink. A common workflow for film editing involves edge-coding printed film simultaneously with the film's synchronized audio track, on 35mm magnetic film, so that a foot of film and its synchronized audio have identical edge numbers. Eastman Kodak began using latent image edge numbering on their manufactured 35mm raw film stocks in 1919.
Keykode
With the popularity of telecine transfers and video edits, Kodak invented a machine readable edge number that could be recorded via computer, read by the editing computer and automatically produce a "cut list" from the video edit of the film. To do this, Kodak utilized the USS-128 barcode alongside the human-readable edge numbers. They also improved the quality and readability of the human-readable information to make it easier to identify. The Keykode consists of 12 characters in human-readable form followed by the same information in barcode form. Keykode is a form of metadata identifier for film negatives.
Keykode deciphered
An example Keykode: KU 22 9611 1802+02.3
The first two letters in the Keykode are the manufacturer code and the stock identifier, respectively ; each manufacturer has different stocks' naming convention for their emulsion codes.
The next six numbers in the Keykode are the identification number for that roll of film. On Kodak film stocks, it remains consistent for the entire roll. Fuji Stocks will increment this number when the frame number advances past "9999".
Computers read the frame offset by adding digits to the Keykode after the plus sign. In this case, a frame offset of two frames is specified. The number of frames within a film foot depends on both the film width and the frame pulldown itself, and can also be uneven within the same roll, but rather repeat periodically.
The last, dot-separated number is the perforation offset which, if preceded by a frame offset like in the above example, is a bias within the just-specified frame; otherwise this considered to be an offset within the whole film foot.
EASTMAN 5279 167 3301 122 KD
These numbers are consistent for a whole batch of film and may not change in many rolls. EASTMAN is the film manufacturer, 5279 is the stock type identifier. The next three numbers is the emulsion batch number. The next series of four digits is the roll and part code, followed by the printer identification number that made the Keykode and finally a two letter date designation. In this case, KD=1997.
