In a model scroll created in the lab, ink containing lead stood out in an X-ray scan even after the papyrus was burned. Now it remains to be seen which ancient scrolls the method might be useful for.
Nearly two thousand years after the eruption of Mount Vesuvius, hundreds of papyrus scrolls found in Herculaneum still hold some of their secrets. They were saved from the disaster precisely because they were burned, but their black, brittle layers could crumble if they were tried to open. A team of researchers from the United States and Britain chose an unconventional way to test a solution: write a new scroll, burn it under controlled conditions, and then try to read the writing without unfolding it.
In an experiment published September 16, 2026 in the journal PLOS ONE, the researchers were able to read lead-based ink on a model scroll using X-ray computed tomography and digital diffraction. This is a proof-of-concept on modern papyrus; the study does not report deciphering an original ancient scroll using this method.
Why is it difficult to see the ink inside a burnt scroll?
In the Herculaneum scrolls, buried in the eruption of 79 AD, both the papyrus and the black ink are largely carbon-based. After charring, ordinary X-rays have difficulty distinguishing the letters from the surface on which they were written. Advanced scanning and computer processing have already allowed other researchers to read parts of ancient scrolls, but the ink's faint character remains a major obstacle.
Lead changes the image. It absorbs X-rays very differently than charred papyrus, so a small amount of it in the letters can add contrast to the scan. The lead may be a component of the ink or come from the material used to make it; the origin of the metal in ancient examples is still being investigated.
A test scroll instead of jeopardizing an ancient source
The team used modern papyrus and black ink to which they added varying concentrations of lead salt. After writing, they charred the scroll in heat and in the presence of little oxygen. The model scroll became brittle, similar to ancient scrolls, so that physically opening it would have damaged it.
Instead of opening it, the researchers scanned it with a laboratory X-ray system, assembled a 3D image from the measurements, and traced the convoluted layers in software to show them unfolded. The writing created with lead-based ink became legible in parts of the image. In a separate experiment, a portable X-ray fluorescence instrument detected lead in the charred scroll without touching it. In contrast, ink containing only carbon was much harder to detect in simple X-ray images.
What will it take to get to the original scrolls?
The researchers suggest using lead testing as a way to sort scrolls before detailed scans: If metal is found in the writing of a particular scroll, it may be easier to extract text from it. In addition, the model scrolls provide image processing researchers with examples where the placement of letters is known in advance, to test and improve algorithms.
Lead has already been found in writing on several ancient remains, including two fragments of the Herculaneum Scrolls, but there is no systematic survey yet showing how many of the closed scrolls contain it. Even the laboratory experiment does not guarantee that a two-thousand-year-old scroll, with a different structure and composition, will be equally easy to read. The next step is to test the proposal carefully on original material, subject to its preservation and the approval of the collections that hold it.
Questions and Answers
Did the researchers read an ancient scroll from Herculaneum?
No. They read writing on a modern papyrus scroll that they created, burned, and scanned. There are ancient scrolls that have been partially deciphered in other projects, but that is not the result of the new experiment.
Why look specifically for lead in ink?
Lead creates a stronger contrast between the writing and the charred papyrus in an X-ray scan. Its non-invasive examination could help select scrolls that are more likely to be read digitally.
The scientific article
More on the subject on the science website
- Researchers used computed tomography to decipher scrolls burned two thousand years ago
- The wonderful story behind reading burnt scrolls
Source: The study in PLOS ONE; University of California, Berkeley Announcement
