Knowledge Base

Overview

A Truestamp beacon is a block hash nobody could have predicted before Truestamp published it. Printing one and holding it in frame is the paper form of that fact: a photograph or a recording showing the printed hash cannot have been made before the beacon existed, because until that moment the value on the page was unknowable. This is the same trick as holding up a current newspaper in a proof-of-life photograph, with a hash in place of the front page and a public verification page in place of the reader’s memory of that day’s headline.

The artifact prints from the beacon print page in three form factors, and each carries the same four things: the Truestamp logo, a QR code, the beacon hash in eight four-byte groups, and the beacon’s UTC time.

What the page hands you is a PDF that Truestamp renders, not a web page for the browser to print. The image on the preview page is that same document rendered as a picture, so what you approve on screen and what reaches the paper are one description of the artifact rather than two that have to agree.

Read the direction of the claim carefully, because it only runs one way. The paper establishes that the photograph is not older than the beacon. It says nothing about how much newer it might be, and it does not prove when the photograph was taken.

Before you begin

Nothing is required. The page is public, needs no account, and holds no state.

Beacons are minted about once a minute, so the value you print is current only briefly. That is the point: a stale beacon still proves the photograph is not older than it, so an artifact keeps its meaning indefinitely, but the interval it establishes only tightens if you print a fresh one close to the event.

Steps

1. Pick the beacon. Open https://www.truestamp.com/beacons/print for the most recent beacon, or https://www.truestamp.com/beacons/<hash>/print to pin a specific one. A pinned address always reprints the same beacon, so a run of lanyard badges and the speaker’s lectern sheet can carry one shared value, and any of them can be reprinted later unchanged.

2. Pick the form factor from the control bar at the top of the page. The bar is screen-only and never reaches paper.

   Form factor	Size	Stock
   Lectern sheet	US Letter (215.9 x 279.4 mm)	Plain paper, one beacon to the page
   Lanyard portrait	3 x 4 in (76.2 x 101.6 mm)	Plain paper, one card centred on a US Letter page with a cut guide
   Lanyard landscape	4 x 3 in (101.6 x 76.2 mm)	Avery 5392, 6 per sheet

   Every form factor is a US Letter page, because a PDF carries its own page size rather than taking whatever is in the tray. The lectern sheet is drawn to survive that: its content sits in a 186 mm column, which is what both Letter and A4 have to spare, so printing it on A4 at actual size trims only margin. The six-up lanyard sheet cannot be, since the Avery 5392 grid is sized to Letter exactly.

   The lectern sheet is meant to be taped to a podium or held up, and its QR code is sized to survive being photographed across a room. The lanyard cards are meant to be worn, so every photograph taken of the wearer carries one.

3. Open the artifact. Print opens the PDF in a new tab and hands it to whatever PDF viewer the device has, which is what owns the print and share controls. Download PDF saves the same file instead. On a phone this is the step that matters: the platform’s viewer prints the sheet as drawn, where a browser printing a web page would repaginate it and stamp its own header across it.

4. Print at 100% scale, on matte paper, with margins left on Default. The artifact is pure black on white and needs no background graphics, so it prints correctly on a black and white laser printer at the default settings.

Verify

Scan the QR code. It resolves to that beacon’s verification page at https://www.truestamp.com/verify/beacon/<hash>, which independently confirms the hash and shows the beacon’s place in the chain. The code carries the verification page rather than the beacon’s informational page, because somebody scanning a sheet out of a photograph wants to check the value rather than read about it.

Compare the hash on the paper against the hash on the page. They must match exactly, in all eight groups.

For a reader who cannot scan the code, the artifact also prints the address https://beacons.truestamp.com beside the timestamp as a typed fallback.

The printed UTC time is a convenience for close reading, not evidence. It is derived from the beacon’s own identifier rather than from the moment you hit print, so the paper cannot disagree with what a scan reports, but a timestamp on paper is trivially forgeable and proves nothing on its own. The hash is the part that carries the proof.

Limitations

• It establishes one edge, not an interval. The artifact proves a photograph is not older than the beacon in it. Pairing it with a later Truestamp submission of the photograph itself is what pins the photograph inside a submission window.
• It proves nothing about the subject. Anyone can print any beacon. The paper says the photograph is not older than the beacon; it does not say who was photographed, where, or that anything else in the frame is genuine.
• The code has to be readable. A hash nobody can scan or transcribe out of the image carries no proof, which makes print quality and framing part of the evidence rather than a presentation detail.

Troubleshooting

• The page says no beacon to print. Either the pinned hash does not match a published beacon, or no beacon has been minted yet. The beacon index is the place to find a current one.
• The QR code does not scan from a distance. Scaling below 100% shortens the range the code reads from, and gloss paper can flare under stage lighting. Print at full scale on matte stock.
• The lanyard landscape cards do not line up with the label sheet. The Avery 5392 grid is sized to US Letter exactly: two 4 x 3 in cells across 215.9 mm, three down 279.4 mm, with no gutters. On A4 that grid is 5.9 mm too wide, so the outer column clips at actual size and every card walks off its die-cut at fit-to-page. Print it on US Letter, which is the only stock that Avery product is sold on.
• Print does not open anything. The button opens the PDF in a new tab, which some in-app browsers refuse to do. Use Download PDF and open the saved file; it is the same document.