What is it?
Film timecode is printed on the film in the camera. The actual TC is a machine readable matrix with human readable (ie. numbers) every second or so. Aaton Code is the most widely supported film TC format.
What is it for?
Film timecode can serve two functions.
The first is to expedite the telecine process. When film TC and (matching) Nagra or DAT TC are employed in production the dailies can be synched up much more quickly. In such a situation, a TC slate should be used and each take marked as per usual. This way the telecine operator has the sticks to fall back on if the film or Nagra/DAT TC is screwed up.
The second way film TC can be used is in situations where a traditional slate is undesirable. The most common example of this is documentary production.
What special technical requirements are there?
There are only three things you need to properly employ film TC. The first, and most obvious, is a camera that is outfitted with TC. The SRIII fits the bill.
The second thing you’ll need is a TC DAT or TC Nagra.
The third thing you’ll need is a telecine facility that can actually read the TC on the film. This is the most difficult of the three components to find.
Oh, and there is one more thing you’ll need. You need and Assistant Camera Operator (AC) who knows how to operate the camera TC and a Mixer who knows how to co-ordinate TC synching issues with the AC. This human component is extremely important.