Blockchain timestamping for photographers
By BlockchainSignLast updated
Metadata is the first thing to disappear when an image is lifted, and it was never strong evidence in the first place — EXIF is trivially editable. A hash anchored to a public ledger is not.
The problem with the evidence you already have
Photographers usually assume the RAW file settles it, and it mostly does — possession of the original is strong. The weakness is the date.
EXIF is written by your camera and editable by anyone with a text editor. File system timestamps follow whatever the machine's clock said. A platform's upload date proves when it reached the platform, not when it was taken, and it disappears when the account does.
None of that is a problem until someone with the same image disputes who had it first.
What a timestamp adds
A dated, tamper-evident anchor on the exact file. Not "a photo like this" — this precise sequence of bytes, existing no later than a specific Ethereum block, verifiable by anyone forever.
Combined with the RAW original, that is a strong position: you hold the file nobody else has, and you have an independent record that you held it on a date you did not choose.
When to do it
Before delivery. Client work leaves your control at delivery. A record predating it separates "your copy" from "the copy you gave them".
Before publication. Once an image is public it can be lifted within hours. The record needs to predate that.
Before licensing negotiations. Particularly with a party who might decide to use it without concluding a licence.
On the RAW, not the JPEG. Timestamp the file you alone hold. A hash covers exact bytes, so the exported JPEG is a different file with a different hash — timestamp the original, and the export separately if it matters.
Why nothing is uploaded
Unpublished work should not be sitting on a third party's server, and a large RAW library would be a nuisance to upload anyway.
The file is hashed in your browser with the Web Crypto API and only the 64-character hash is transmitted. A 60 MB RAW never leaves the machine. You can watch the network tab and confirm there is no request carrying the image; the free hash tool runs the same code with nothing sent at all.
What it proves
That the file existed by that date, unchanged. Not that you took it — someone who copies an image can timestamp the copy, and the ledger will honestly record that they had it on that date.
What defeats that is being earlier, and holding the original. A timestamped RAW made before publication, plus the RAW itself, plus the rest of the shoot, is a considerably better position than a copyist has. See proof of existence vs proof of authorship.
For registration — which in the US is what unlocks statutory damages and is required before suing — see how to copyright a photo. A timestamp is not a substitute for it, and for a photographer who enforces regularly, registration is the more important step.