New trick could reveal text on 2,000-year-old scrolls charred by eruption of Mount Vesuvius

The long-lost words of ancient philosophers may finally be revealed nearly 2,000 years after the violent eruption of Mount Vesuvius scorched and buried them, thanks to a heavy metal that was used in the ink that penned them, a new study finds.

The new research investigates the lead-enriched ink within some of the nearly 2,000 papyrus scrolls, which were found at a villa in the ancient town of Herculaneum in the 1750s. In a new paper, a team created modern scrolls with leaded ink, scorched them and found that they could read the text after using several techniques, including X-ray technologies and artificial intelligence (AI).

"It's amazing what you can get electrons to do," Douglas Seiler, a research affiliate of the University of California, Berkeley and a co-author of the study, said in a statement about the new method.

Over the past few years, other researchers have digitally opened and decoded some of the scrolls from the Herculaneum villa, which was likely owned by Julius Caesar's father-in-law. These results have helped reveal the writings of ancient philosophers, largely Epicureans and Stoics, with one section even describing Plato's final burial place.

But scientists still wrestled with using X-rays to read the scrolls, since, in many cases, both the papyri and the ink written on them are carbon-based. However, some of these papyri, scientists have learned, contained leaded ink. The new study, published Wednesday (Sept. 16) in the journal PLOS One, suggests that researchers should first scan the scrolls for leaded ink and then use their new technique to read more of these long-lost texts.

This method could help improve text-detection algorithms to identify writing on ancient papyrus pages, they noted. And, in the long run, it may help to protect the scrolls.

"This provides a low-risk method to develop algorithms without endangering the priceless artifacts," the team wrote in the study.

Virtually unrolling a scroll

When Mount Vesuvius erupted in A.D. 79, it buried Herculaneum under 70 feet (20 meters) of volcanic rock and ash.

Along with the 2,000 people who died at Pompeii and Herculaneum from this natural disaster, many of the scrolls housed at the Herculaneum villa were carbonized, or essentially turned into charcoal, trapping their writings in brittle rolls of papyrus that are nearly impossible to read without destroying the scroll itself.

But, given that some of the ink used in the scrolls contained lead, Seiler and his colleagues decided to do a little experiment. They created a fake papyrus scroll with lead-based ink and "carbonized" it to try matching the conditions of the scrolls found at Herculaneum.

Next, the researchers used X-ray fluorescence, which determines the elements in a material by how they interact with X-rays, to determine that these scrolls did, in fact, contain ink with varying levels of lead. Following that, they used X-ray tomography, a way to make a 3D image using X-rays, with custom-made software to re-read some of the text they had produced on their scroll.

Thanks to their technique, the researchers found that they could read the lead-based ink writings in the scrolls, even with minuscule levels of lead. While not all the writings could be deciphered, the method was able to detect differences between the text and the papyrus it was written on.

This technique, if used on other Herculaneum scrolls, could give these ancient writings a "higher probability of being successfully read," they wrote in the study.

How much do you know about the Roman town destroyed by Mount Vesuvius? Find out by taking our Pompeii quiz.