Legal evidence
A chain of custody for evidence photography, from card to exhibit
Photographs get admitted because the photographer testifies to what they show. What that testimony needs today is protection against the objection that a file could be AI-generated or edited after the fact. Lumethic gives every frame a third-party timestamp on the day of the shoot and gives the selected images a forensic verification the other side can examine.
The problem
"How do we know this file hasn't been changed?"
Between the shoot and the courtroom, a photograph passes through cards, laptops, editing software, and email. Without records, the honest answer to when a file could last have been altered is "any time before today". That gap is exactly where cross-examination goes, and AI image generators have made the challenge routine.
One thing first: we build software and do not give legal advice. The attorneys running the case should define what they need from the photography, ideally in writing before the first shoot. What we provide is the technical record that supports the photographer's testimony.
What you get
Records for every stage of the work
Every frame, anchored on the shoot date
When you back up a card with a tool like OffShoot, Silverstack or ShotPut Pro, Lumethic anchors the tool's hash list with an independent timestamp authority. The receipt proves every file on the card existed, exactly as it is, no later than that day. One receipt covers the whole card.
Forensic verification of the selects
The frames that go to the attorneys or become exhibits get a full RAW and JPEG comparison: sensor checks, structural similarity, recapture detection, metadata consistency. Because the files match the anchored list, the report shows the chain from capture to verification.
Exhibits that carry their own proof
The Lightroom plugin checks on export that the JPEG derives from the verified RAW. Normal processing passes, content manipulation fails, and the export carries C2PA Content Credentials. Reports and receipts are shared with the legal team via link; nobody needs an account.
How it works
From the memory card to the exhibit
The record starts on the day of the shoot and follows the images through selection, processing, and handover. Each stage produces something the legal team, and the other side, can check.
Anchor the card after the shoot
Back up the card with your offload tool. It writes a hash list of every file; upload that list and Lumethic has it timestamped by an independent authority. The receipt covers the whole card and proves every frame existed unchanged on the shoot date.
Verify the selects
When the relevant frames are chosen, submit each one as a RAW and JPEG pair. The forensic comparison covers sensor characteristics, structural similarity, recapture detection, and metadata consistency, and the files match the anchored list.
Export exhibits through Lightroom
The plugin checks on export that the JPEG derives from the verified RAW. Normal processing passes, content manipulation fails, and the exported file carries C2PA Content Credentials.
Hand over via link
Reports and receipts are shared with attorneys and experts through private links. Nobody needs an account, and each record contains what is needed to check it with standard cryptographic tools.
A worked example
Ten days of field documentation, end to end
Here is how the pieces fit together on a typical engagement: a commercial photographer hired to document a scientific sampling study whose results are headed for litigation.
Before day one
The attorneys put in writing what they need from the photography. The photographer sets the camera's date, time, and time zone, configures it to write RAW and JPEG, and runs a test offload to confirm that the hashes of the card copies match the tethered copies. The offload tool is set to C4 checksums. A Basic plan is enough to start.
Each shoot day
After shooting, the card's write-protect switch goes on and the card is backed up in the field. The offload tool writes its hash list and uploads it automatically, so every card is anchored with an independent timestamp on the day it was shot. Field notes reference the card labels. Ten days of shooting produce a stack of receipts that together cover every frame taken, well inside the monthly allowance.
Selection, weeks later
The legal team picks roughly a hundred frames for the expert report. The photographer verifies each one as a RAW and JPEG pair. Because the files match the anchored lists, every report shows the chain: captured, offloaded and anchored on the shoot date, verified. Nothing else from the shoot needs verifying.
Exhibits and handover
Exhibit files are exported through the Lightroom plugin, which confirms each JPEG derives from its verified RAW and embeds Content Credentials. Reports and receipts go to the attorneys as links. When the opposing expert wants to check the record, the receipt verifies with standard tools, without trusting anyone's word for it.
The result: when the after-the-fact objection comes, the answer is not an argument but a stack of records, each one independently checkable, reaching back to the day the shutter fired.
In the courtroom
Built to back up testimony, not replace it
Hashing and verification do not make a photograph admissible by themselves. They protect the testimony that does, and every part of the record can be examined by the other side.
- Offload receipts contain everything needed to check them with standard cryptographic tools, independent of Lumethic, and there is a public page where anyone, including opposing experts, can verify a receipt directly.
- Verification reports state their methodology, scores, and confidence levels, so the analysis can be explained and defended rather than presented as a black box.
- The record answers the after-the-fact objection: it shows the files existed unchanged from the shoot date, and that the exhibit derives from the verified camera original.
Questions from evidence work
Set up the record before the first shoot
Both paid plans include card offloads and the Lightroom plugin. Card receipts cover every frame; verification is only needed for the selects, so most cases fit the Basic plan and a busy case fits Professional. Monthly billing, no term commitment.