The edge numbers serve a number of purposes.

The edges are stored in an array, so the edge number is its array index.

Laboratories can also imprint their own edge numbers on the processed film negative or print to identify the film for their own means.

To do this, Kodak utilized the USS-128 barcode alongside the human-readable edge numbers.

Frames of workprint and of original negative are matched exactly through the use of edge numbers that appeared on each frame of original and work print.

The negative cutter will translate the Timecode in the EDL list to edge numbers (keykode) using specially designed negative cutting software to find which shot is needed from the rushes negative.

The list of transitions produced by the first program is sorted (numerically, by the first node number), and the node numbers are converted into edge numbers, by a simple nawk (Aho et al, 1988) program.

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.

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.

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.

Keykode (also written as either KeyKode or KeyCode) is an Eastman Kodak Company advancement on edge numbers, which are letters, numbers and symbols placed at regular intervals along the edge of 35 mm and 16 mm film to allow for frame-by-frame specific identification.