AI & Archaeology · Buried AD 79 · Herculaneum, Campania, Italy
Scientists burn homemade scrolls to show lead ink could help read Herculaneum papyri
In test scrolls charred in a furnace, letters written with leaded ink stood out brightly in X-ray scans, a stronger signal for the software and AI that read closed scrolls.
Peer-reviewed paper
Herculaneum, Italy A team led by Douglas Seiler has made and burned its own papyrus scrolls to test a new way of reading the Herculaneum library. In X-ray scans, letters written in ink containing lead stood out brightly against the charred papyrus. The study is published in PLOS One.
The real scrolls were buried when Mount Vesuvius erupted in AD 79. Ash and rock covered Herculaneum, near modern Naples, and extreme heat carbonised its library into fragile black rolls. More than 1,800 scrolls and fragments survive. Some contain works by the Epicurean philosopher Philodemus.
Reading them without unrolling them is hard. X-ray tomography, or X-ray CT, maps the layers inside a closed scroll from a series of scans. But the ink and the papyrus both contain carbon. As a result, carbon-based ink often shows too little contrast against the burned papyrus.
Test scrolls written by students
Seiler's team focused on lead, which absorbs X-rays far more strongly than charred papyrus. If an ancient ink contained lead, its letters should stand out in a CT scan. To test this, Seiler prepared lampblack ink with different amounts of lead. High school students then wrote passages on new papyrus with reed pens.
The team rolled up the sheets and heated them in a low-oxygen furnace. The charred rolls had tightly packed, wavy layers. According to the paper, these will challenge unrolling algorithms.
Two X-ray methods, X-ray fluorescence and CT, detected lead at every concentration tested. Even 25 micrograms per square centimetre was visible in the scans. That is 25 millionths of a gram on each square centimetre of papyrus. According to the researchers, leaded ink absorbs up to 25 times more X-rays than the charred papyrus around it.
lit up like a Christmas tree
Douglas Seiler, who led the study, describing the leaded letters in the scans
The team proposes a cheap first step. An inexpensive handheld X-ray fluorescence scanner could screen scrolls for lead. Only selected pieces would then go on for high-resolution CT imaging.
The researchers also tested software for virtually unrolling the burned scrolls. Michael Cyrus Daugherty adapted code first written to map the inner layers of lithium-ion batteries. The program followed the uneven thickness of the scroll and produced a flat, unrolled view with visible text.
A known answer for training AI
Artificial intelligence already helps read Herculaneum scans. The Vesuvius Challenge drove efforts to read CT scans of closed scrolls. In 2024, AI helped researchers recover 15 columns from one scroll, an Epicurean work about perception and pleasure. In 2026, another team used AI to read part of a damaged scroll called PHerc. 1667. That text appears to discuss Stoic philosophy and could date to the second or third century BC.
Those results relied on faint differences in the scans that come from the ink. Lead would give a much stronger signal. The model scrolls also give software a check it cannot get from the real library. The researchers know exactly what text is inside each one. They can compare the computer's output with the original writing and use the results to train better algorithms.
The study has clear limits. All the tests were on modern model scrolls. It does not show how many Herculaneum scrolls, if any, contain leaded ink. Only a few scrolls have been virtually opened and read so far. None had been systematically tested for lead before this work.
The researchers suggest screening the surviving scrolls for lead. That could pick out the texts where X-ray CT and AI have the best chance of recovering hidden writing.
Sources
Paper: Seiler et al., PLOS One (2026)
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