File handling and backup on set — the DIT role and the 3-2-1 rule

A good filming day can end as a disaster if the material disappears before it reaches the edit suite. That's the background for why larger productions have a dedicated role — DIT Digital Imaging Technician — whose only job is to copy check and organize the shot material while the rest of the team continues filming.

The DIT works in parallel with recording, not after. As soon as a memory card is full, the DIT takes over: the card is copied, the copy is verified, and only then is the card released to be formatted and reused. On smaller productions there is not always budget for a dedicated DIT, but the task doesn't disappear for that reason — it lands instead with the photographer, editor or production manager, and it still needs to be solved systematically.

• 013 copies of the material in total (including original)
• 022 different types of media — e.g. an internal drive and external hard disk, not two identical disks from the same batch
• 031 copy stored at a different location than the others (offsite), so a fire, theft or flood does not affect all copies at once

Backup is Something That Cannot Be Thought Through Afterwards — It Must Be a Fixed Part of Production Planning Already Before the First Shoot Day. This Means There Must be Time Set Aside in the Schedule for Copying Between Shoots, There Must be Purchased or Leased Enough Drive Space for the Entire Production's Expected Data Volume, and It Must be Clear Who is Responsible if IT or the Person in Charge is Sick or Absent One Day. A Production that Only Discovers There is a Lack of Drive Space in the Middle of a Shoot Day Loses Valuable Time While the Problem is Solved Acutely.

A file that appears to have been copied correctly can in rare cases be silently corrupted during transfer without anyone noticing until the file is needed. The solution is a checksum — a mathematical fingerprint of the file's contents calculated both before and after copying. If the two fingerprints are identical the copy is provably a byte-for-byte faithful reproduction of the original not just a file that looks right.

On a production with several shooting days and many cards, a consistent folder structure is not a matter of neatness, but of being able to find and recreate the order of what was filmed when. Naming by date, production, and card number makes it possible to trace a clip back to exactly which card and which day it comes from — something that becomes essential when something needs to be found or recreated after an error.

If a card is lost anyway, or a corrupted file is discovered, it is crucial that it is reported immediately — not hidden in the hope that it will resolve itself. The faster the rest of the team knows that a scene is missing or damaged, the greater the chance that it can be reshot while the location, cast and equipment are still available. A DIT who discovers and admits an error immediately often saves production; a DIT who stays silent and hopes rarely does anything other than make the damage worse.

Backup Work Does not Stop When the Finished Program is Delivered. The Original Raw Material Should be Archived for a Period After Delivery, Both Because the Channel or Customer May Ask for a Rerun in a Different Format, and Because Parts of the Material May Prove Useful in a Later Production. A Production that Deletes all Material as Soon as Delivery is Approved Saves Space Today — but Simultaneously Removes the Possibility of Easily Correcting an Error, Complaint or Technical Deficiency Discovered After Delivery.