Light Billions of Times Brighter Than the Sun Used to Read Charred Scrolls From Herculaneum

The eruption of Mount Vesuvius in 79 A.D. carbonized papyrus scrolls, which may now be readable

Charred Scroll
One of the scrolls being scanned by the Diamond Light Source and digitally deciphered. Diamond Light Source

Researchers are hoping that a new technology will help them to begin reading charred scrolls dating back 2,000 years. If successful, the technique could help decipher other charred, faded or damaged scrolls and documents from the ancient world.

These particular scrolls were unearthed in 1752 in the ruins of Herculaneum, which was covered in ash by Mount Vesuvius in 79 A.D. They were discovered, specifically, in the library of a grand villa, believed to belong to Julius Caesar’s father-in-law, Lucius Calpurnius Piso Caesoninus. As Nicola Davis at The Guardian reports, the documents were a major find, since the site, which became known as the Villa of the Papyri, is the only known intact library from the ancient world. Most of the documents, however, were charred into rolled up logs, rendering the texts more or less useless.

“Although you can see on every flake of papyrus that there is writing, to open it up would require that papyrus to be really limber and flexible – and it is not anymore,” Brent Seales, director of the Digital Restoration Initiative at the University of Kentucky, tells Davis.

That hasn’t stopped researchers from trying to access the writings, most of which, it’s believed, were lost to history. Attempts have been made to unroll about half the scrolls using various methods, leading to their destruction or causing the ink to fade.

Seales and his team are now seeking to read the text using the Diamond Light Source facility, a synchrotron based in Oxfordshire in the U.K. that produces light that can be billions of times brighter than the sun. They will test out the method on two intact scrolls and four smaller fragments from L'institut de France.

“We... shine very intense light through (the scroll) and then detect on the other side a number of two-dimensional images. From that we reconstruct a three-dimensional volume of the object... to actually read the text in a non-destructive manner,” Laurent Chapon, physical science director of Diamond Light Source, tells George Sargent at Reuters.

Machine-learning algorithms will then attempt to use that data to decipher what was on the scrolls. “We do not expect to immediately see the text from the upcoming scans, but they will provide the crucial building blocks for enabling that visualization,” Seales says in a press release. Eventually, if the technique works, the team hopes to use it on 900 other Herculaneum scrolls from the villa. “The tool can then be deployed on data from the still-rolled scrolls, identify the hidden ink, and make it more prominently visible to any reader,” Seales says.

The isn’t the first time he’s unrolled ancient scrolls. As Jo Marchant reported for Smithsonian magazine in 2018, Seales began researching techniques for creating 3D images of ancient documents and deciphering faded or damaged scrolls back in 2000. In 2005, he first saw the Herculaneum scrolls, most of which are housed in a museum in Naples, and decided he’d focus his technical attention on the documents. “I realized that there were many dozens, probably hundreds, of these intact scrolls, and nobody had the first idea about what the text might be,” he says. “We were looking at manuscripts that represent the biggest mysteries that I can imagine.”

Since then, advancing technology has helped him dig deeper into the documents. In 2016, his team made news when they were able to use micro-CT scans to read a charred scroll found in an ark near the Dead Sea at En Gedi. Because the ink used metals, Seales was able to detect the writing. He then used his advanced software to digitally unroll the scroll and piece it back together to learn that the 1,500-year-old document was snippet from the Book of Leviticus.

But the Herculaneum scrolls pose a different problem: The Romans did not use heavy metals in their carbon-based inks, though some of their inks do contain lead. That makes the contrast between the ink and papyrus not very strong. That’s where the machine learning comes in. Davis reports the team is training its algorithms using bits of charred scrolls where the writing is still visible. The hope is that the software will learn the microscopic differences between parchment where ink once was and wasn’t.

The team has already collected the high-energy X-Ray data from the scrolls and are now training their algorithms. They hope to perfect the process in the next few months.

Most of the writings in open scrolls from the Villa of the Papyri have been philosophical works in Greek on Epicureanism. But there’s a chance that some of the charred scrolls contain Latin texts. It’s also possible that more scrolls remain undiscovered in parts of the Villa that have yet to be excavated. “A new historical work by Seneca the Elder was discovered among the unidentified Herculaneum papyri only last year, thus showing what uncontemplated rarities remain to be discovered there,” as Oxford classicist Dirk Obbink points out to Davis.

If and when the scrolls are revealed, it will be a windfall for historians, classicists and archaeologists alike. “It’s ironic, and somewhat poetic that the scrolls sacrificed during the past era of disastrous physical methods will serve as the key to retrieving the text from those survive but are unreadable,” Seales says in the press release. “And by digitally restoring and reading these texts, which are arguably the most challenging and prestigious to decipher, we will forge a pathway for revealing any type of ink on any type of substrate in any type of damaged cultural artifact.”

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