A Volcano Toasted This Scroll 2,000 Years Ago. Here’s How Scientists Read It Without Ever Opening It

The library of Herculaneum, the only known intact library from antiquity, consists of roughly 1,800 scrolls and fragments. Most were turned into brittle, carbonized husks when ash from Mount Vesuvius inundated the Italian city in 79 C.E. For centuries, attempts to physically unroll these scrolls often resulted in heaps of ash, leading Italian authorities to halt such efforts after the collection’s discovery in 1752.

The Lead-Ink Hypothesis and Modern Replicas

Reading these scrolls is historically difficult because both the ink and the papyrus are carbon-based, creating low contrast in X-ray scans. To test a new solution, Douglas Seiler, an affiliate of Berkeley SETI, recreated the disaster by burning his own scrolls. Seiler sourced papyrus and reed pens from Egypt and lampblack ink from Japan, then paid high school students to write lines from the Bible, Star Wars, and the TV show The Outer Limits on the material.

After rolling the papyrus and carbonizing it in a high-temperature furnace, the team used X-ray tomography (CT) and X-ray fluorescence to analyze the results. Their findings, published September 16 in PLOS ONE, show that leaded ink creates a signal so strong the letters lit up like a Christmas tree, according to Seiler.

The researchers found that lead concentrations as low as 25 micrograms per square centimeter were visible. Because lead absorbs up to 25 times more X-rays than the surrounding charred papyrus, it provides a clear contrast that carbon-only ink lacks.

Virtual Unrolling and AI Integration

The project doesn’t just rely on chemistry; it uses computer vision to “unwrap” the scrolls digitally. Michael Cyrus Daugherty adapted code originally designed for mapping the inner layers of lithium-ion batteries to follow the uneven thickness of a rolled scroll and produce a flattened view.

This software development is part of a broader effort involving artificial intelligence. The Vesuvius Challenge, a public competition launched in 2023, has used AI to recover text from closed scrolls. In 2024, researchers recovered 15 columns from one scroll containing an Epicurean work on pleasure and perception. More recently, in June 2026, a team deciphered 22 columns of Greek from scroll PHerc. 1667, which appears to be a Stoic treatise on human nature and ethics.

Seiler’s model scrolls provide a critical advantage for these algorithms: because the researchers already know the text they wrote on the replicas, they can use the scrolls as a reference to train AI to interpret scans more accurately.

The Vesuvius Challenge and Open Science

The shift toward virtual restoration was spearheaded by Brent Seales of the University of Kentucky, who began working with Herculaneum scrolls in 2004. Seales eventually partnered with investor Nat Friedman to turn the deciphering process into a global competition. This required Seales’s team to fully disclose their datasets and know-how to the public.

This open-source approach has allowed a community of contributors to refine the tools used to test scroll slices.

Screening the Remaining Library

While AI has already recovered some text, the lead-ink method offers a more efficient way to prioritize which scrolls to scan. The researchers suggest using inexpensive handheld X-ray fluorescence scanners to screen the surviving collection for lead before committing to high-resolution CT imaging.

Currently, the library’s fragments are distributed across Italy, France, and England. While no systematic test for lead has been conducted on the entire collection, one researcher previously found lead in a fragment from an earlier physical unrolling attempt. Many of the scrolls that were successfully opened in the past contained works by the Epicurean philosopher Philodemus.

The potential impact of this screening process is significant.

The next step for the research team is to determine how many of the remaining Herculaneum scrolls actually contain leaded ink, a figure that remains unknown.