Researchers have developed a method to better read carbonized ancient scrolls by identifying lead in their ink, a discovery that could accelerate the recovery of texts from the only known intact library from antiquity. The project, involving a multidisciplinary team of scientists, used modern replicas to demonstrate that leaded ink provides a high-contrast signature that is significantly easier to detect via X-ray than traditional carbon-based inks.
Simulating Ancient Destruction
To test the theory, Douglas Seiler, an affiliate of Berkeley SETI, recreated the conditions that destroyed the library in Herculaneum. In 79 C.E., ash from Mount Vesuvius inundated the Italian city, turning more than a thousand papyrus scrolls into brittle, carbonized husks. Seiler sourced traditional lampblack ink from Japan, papyrus and reed pens from Egypt, and hired high school students to write text from the Bible, Star Wars, and the television show The Outer Limits on the papyrus.
These model scrolls were rolled and burned in a high-temperature furnace to mimic the original Herculaneum scrolls. Physicist Jake LaManna then produced 3D X-ray scans of the charred models at the NIST Center for Neutron Research in Maryland. Seiler noted that the letters lit up like a Christmas tree
during the process. To reveal the text, Michael Cyrus Daugherty of NIST adapted a software program originally designed to unroll CT scans of lithium-ion battery “jelly rolls” to digitally unwrap the model scrolls.
Identifying High-Contrast Scrolls
The research addresses a primary obstacle in reading the Herculaneum collection: the low contrast of carbon ink on carbonized papyrus. Seiler stated that lead in the ink would produce a huge friggin’ signature
and suggested that searching for leaded ink would help the overall deciphering process.
The team found that an inexpensive handheld X-ray fluorescence scanner can identify leaded ink in burned scrolls. This provides a simple way to determine which scrolls are the most promising candidates for further analysis using X-ray CT. While some scrolls from the Villa of the Papyri have been virtually unrolled and read, none have been tested for leaded ink to date.
This methodology may assist efforts like the Vesuvius Challenge, which awarded a $700,000 grand prize in 2024 for producing the first readable text. Recent progress in the field includes the first X-ray image of the inside of scroll PHerc. 172, housed in the University of Oxford’s Bodleian Libraries, and the full reading of PHerc. 1667, which was found to be a philosophical treatise on human moral progress and ethics.
Currently, the remaining 1,800 or so scrolls and fragments from the library are distributed across England, France, and Italy. Because these works were directly from Roman intellectual circles and are not merely copies, Berkeley archaeology graduate student Leah Packard-Grams described the value of the project as practically unquantifiable
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