Evidence is only as strong as the chain that produced it. A PDF that's been emailed three times, opened in five different tools, and re-saved twice arrives in court with question marks. The other side asks: how do we know this is what it was?
You don't need a forensic lab to do this well. You need a discipline.
Preserve the original, work on copies
The original PDF — as received from the source — never gets edited. Save it to a read-only folder, hash it (SHA-256 is fine), and record the hash in your evidence log. Every working copy is derived from the original. When the time comes to prove authenticity, you can re-hash the original and match it against the log.
Redaction without information loss
When you redact for disclosure, the redacted copy is a derivative — never the original. Use redact PDF on a copy, save with a clear suffix (`_REDACTED`), and log what was redacted and why. The court may ask for an unredacted copy in chambers; you must be able to produce the original unaltered.
Numbering and pagination
Apply Bates stamps to disclosed bundles, not to the original evidence. The original keeps its native form so any subsequent forensic examination doesn't have to argue around your annotations. The disclosed bundle is what the other side and the court work from, with its own consistent numbering applied via annotate PDF.
Distribution and tracking
When you send a bundle, log who received it, when, and what version. Password-protect outgoing bundles so casual forwarding leaves a friction step. If you serve a corrected version, change the filename to reflect the version (`v2`, `corrected`) and tell every recipient explicitly — never overwrite the same filename silently.
What survives challenge
The strongest evidence chains are dull. A read-only original, a hash log, derivative working copies with consistent naming, Bates-stamped disclosure bundles, and a service log. No clever workarounds, no exceptions for tight deadlines. Get this right and challenges to authenticity hit a wall.
FAQ
Do I need to hash every PDF?
For evidence intended for court, yes — at least for originals. SHA-256 hashes are quick to generate and small to store. They make later authenticity challenges trivial to answer.
Can I edit metadata on evidence PDFs?
Never on the original. On a derivative for disclosure, removing metadata is fine and often desirable — but document what you removed and why.
What if the original PDF arrives corrupted?
Preserve the corrupted file as-is and request a fresh copy from the source. Don't try to repair the original — repairs are themselves changes that can be challenged.
How long should I keep the evidence log?
For the life of the matter plus the firm's retention policy — typically six years from conclusion of the case, longer for ongoing exposure.
Evidence handling is paperwork in the literal sense. Build the discipline, log everything, and Flint becomes the layer where the dull but vital steps happen. Open Flint and set the habits early.