Scientists Just Jury-Rigged a Dental X-Ray Machine to Read a 300-Year-Old Letter Without Unfolding Its Delicate Paper
The method allows researchers to avoid damaging delicate documents.
March 2, 2021
Virtual unfolding algorithms allow us to read this unopened letter with a paper lock from the Brienne Collection in The Hague, Netherlands. Photo courtesy of the Unlocking History Research Group archive.
Opening a letter may seem like a straightforward task, but that’s only in the age of mass-produced gummed envelopes, first invented in the 1830s.
For hundreds of years before that, many people relied on “letterlocking,” sealing their mail with a sequence of elaborate creases, folds, tucks, and slits. There were hundreds of different ways this could be deployed to secure mail from prying eyes.