UM:Appendix Keycode
Keycodes sre numbers appearing on the edge of film, incrementing once per foot, used to uniquely identify frames for negative cutting. Also known as edgecodes, they are the film equivalent of timecode. The key numbers identify certain traits of the film, including the manufacturer, the stock type, a prefix identifying the roll and a footage count.
A keycode has a format : KZ 12 8506 2190 +05
where :
KZ |
Manufacturer code - KZ is Kodak |
12 8506 |
Prefix identifies film roll |
2190 |
The count is 4 digits that increment once per foot (35mm film, 4 perf = 16 x 4 perfs per frame) |
+05 |
Offset - how many perforations the frame is from the keycode mark |
Using the count and offset values we can calculate the frame location, as long as we know how many perforations there are per frame and per count.