The procedure replicated what happened to more than a thousand papyrus scrolls in a library in the Italian city of Herculaneum, when ash from Mount Vesuvius inundated the city in 79 C.E. and turned ancient learning \u2014 some likely unknown today \u2014 into brittle, carbonized husks. The eruption, which also buried nearby Pompeii, preserved for posterity the only known intact library from antiquity.<\/p>\n
Seiler\u2019s goal was to determine whether it\u2019s possible to read the text on carbonized scrolls without unrolling them and reducing them to black dust. The key, he hypothesized, was that inks that contain lead would stand out when a scroll is scanned by an X-ray beam, and that computer algorithms could virtually unroll the scroll to reveal the hidden text.<\/p>\n
In a paper published today<\/a> (Sept. 16) in the journal PLOS ONE, Seiler and his collaborators, including a range of Berkeley experts, report that even minuscule amounts of lead in the ink make the letters readable by X-ray tomography, or X-ray CT. The lead absorbs up to 25 times the X-rays absorbed by the charred papyrus, making the inked letters stand out.<\/p>\n Courtesy of Douglas Seiler<\/p>\n \u201cWith lead in the ink, you would get a huge friggin\u2019 signature, so you really need to be looking for scrolls with lead in them,\u201d Seiler said. \u201cThey\u2019re having problems reading a lot of them because of the low contrast of carbon ink on carbon paper. We\u2019re relatively certain that if they start searching for lead, or they let us search for lead, it will help this whole process. This is the Holy Grail.\u201d<\/p>\n In the paper, the researchers also showed that an inexpensive handheld X-ray fluorescence scanner can easily detect leaded ink in a burned scroll, providing a simple way to identify those scrolls that would be more easily deciphered using X-ray CT.<\/p>\n To date, only a few charred scrolls from the Villa of the Papyri at Herculaneum have been virtually unrolled and read and none of them were tested for leaded ink. Though no one has systematically looked for leaded ink in the scrolls, at least one researcher found lead in the ink of a fragment that remained from earlier efforts to physically unroll some of them. Most of those attempts followed the scrolls\u2019 discovery in 1752, but when unrolling mostly produced heaps of ashes, the Italian authorities called a halt to such efforts.<\/p>\n Of those physically unrolled, all have been texts unknown to scholars, many of them written by the Epicurean philosopher Philodemus, who lived in Herculaneum a century before the Vesuvius eruption. Currently, what remains of the library\u2019s 1,800 or so scrolls and scroll fragments are housed in Italy, France and England.<\/p>\n \u201cAlmost everything from antiquity has been destroyed,\u201d Seiler said. \u201cThere\u2019s very little left except papyrus that was in a dry climate or some works that were copied by scribes and transferred down. But some of the Herculaneum scrolls aren\u2019t copies. These are books directly from the ancient world frozen in time. They\u2019re actually from Roman intellectual circles.\u201d<\/p>\n Brandon Sanchez Mejia for UC Berkeley<\/p>\n \u201cThe value in this project is practically unquantifiable,\u201d said Berkeley archaeology graduate student Leah Packard-Grams, who consulted on the project as a papyrologist. \u201cThe stakes are the largest in the history of Greek literature.\u201d<\/p>\n As someone enamored of the ancient Greek and Roman world, Packard-Grams mourns the many lost works of philosophy, science and literature that disintegrated before they could be copied for posterity. She is now translating Greek and Egyptian writing on ancient papyri housed at UC Berkeley in the Center for the Tebtunis Papyri in the Bancroft Library. Unlike the Herculaneum papyri, these were preserved in the dry sands of Egypt. One set of fragments was written by a man named Dionysios, a school teacher and scribe-for-hire, who recorded his mundane daily activities, down to the costs of food he bought for his children along the canal.<\/p>\n \u201cThis is what drew me to papyrology \u2014 that I could read the words of ancient people not through a library book or through a Renaissance copy but actually sit down and know that someone wrote this letter to whomever, his father or something,\u201d she said. \u201cIt\u2019s autograph history \u2014 not just from a book, but from what they were actually writing.\u201d<\/p>\n Lucky for Seiler, Packard-Grams has studied the ink chemistry of Egyptian papyri in Berkeley\u2019s collection. She has hopes that the composition of ink \u2014 traditionally made from soot, water and a binder like gum Arabic \u2014 can provide a signature allowing her to identify the author of a specific text. Any metals in the ink, accidental or purposely added, would help in this identification.<\/p>\n The Tebtunis papyri are fragments of scrolls dating from between 300 B.C.E. and 300 C.E. and were excavated for UC Berkeley 126 years ago at the site of the ancient city of Tebtunis. Using a hand-held X-ray fluorescence scanner, Packard-Grams confirmed that some of these scrolls \u2014 generally those inscribed after the first century C.E. \u2014 are written with ink containing lead and\/or copper. That bodes well for finding lead in some of the Herculaneum scrolls.<\/p>\n Douglas Seiler<\/p>\n \u201cIf we know that the Herculaneum papyri have lead in them \u2014 some of them do, some of them don\u2019t \u2014 then when they take the CT scan, they can scan it with a sensitivity for the element lead and we can see where the ink is,\u201d she said. \u201cAs you unroll it, you can map the letters a lot more clearly.\u201d<\/p>\n Seiler also tapped the expertise of retired Berkeley chemists David Kreimer and Elena Kreimer, a retired manager of the College of Chemistry\u2019s Microanalytical Facility. With their help, he added calibrated amounts of lead \u2014 in the form of lead nitrate \u2014 to lampblack ink to get samples with different lead concentrations. Seiler asked the children of friends to write passages on a new papyrus scroll using traditional reed pens and the various lead-spiked inks. Packard-Grams and Jesse Obert<\/a> of the Archaeological Research Facility<\/a> scanned these newly created scrolls to confirm the lead concentration of the inks used to inscribe the papyrus.<\/p>\n Seiler then carbonized the scrolls in his home lab by placing them inside a semi-sealed steel container containing very little oxygen and heating it in a high temperature furnace. Using his connections at the Space Sciences Laboratory, Seiler was able to find and enlist the help of Jake LaManna, a physicist at the Center for Neutron Research at the National Institute of Standards and Technology in Gaithersburg, Maryland. LaManna gladly created a 3D X-ray CT scan of the charred scroll with the center\u2019s laboratory X-ray source.<\/p>\n \u201cIt\u2019s the first scroll I\u2019ve ever done,\u201d he said. \u201cI don\u2019t tend to say no to interesting projects.\u201d<\/p>\n LaManna jury-rigged a stand for the charred scroll and rotated it in an X-ray beam, recording thousands of slices that were turned by computer into a 3D rendering. Because lead absorbs more X-rays, the leaded ink stood out as bright spots against the darker paper, like an underexposed portion of a black-and-white negative. Ink with a lead concentration as low as 25 micrograms per square centimeter was easily detected both by X-ray CT and X-ray fluorescence.<\/p>\n Douglas Seiler<\/p>\n \u201cIf you look at the images, the letters light up like a Christmas tree,\u201d Seiler said.<\/p>\n Coincidentally, a postdoctoral fellow at NIST, Michael Cyrus Daugherty, had developed a program to unroll CT scans of the \u201cjelly rolls\u201d inside lithium-ion batteries, and LaManna asked if that algorithm would work with the scrolls.<\/p>\n \u201cHe got excited and ran off with the data and within a couple of days and after just a couple little tweaks to his program, he came back with examples of the scroll unrolled,\u201d LaManna said. \u201cHe just had to tweak his code to follow the uneven and changing thickness along the length of the scroll.\u201d<\/p>\n The Vesuvius Challenge<\/p>\n In 2009, Brent Seales at the University of Kentucky was the first to take micro-CT scans of a Herculaneum scroll \u2014 one owned by the Institut de France \u2014 and in 2015 he revealed a successful digital unrolling of a charred scroll from a synagogue that burned in about 600 C.E.<\/p>\n Douglas Seiler and the EduceLab, Univ. of Kentucky<\/p>\n![\"two](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/09\/SeilervanBibber.jpg\")
Douglas Seiler (left) with Karl van Bibber, who is examining the ink on a contemporary scroll to confirm Seiler\u2019s calculations on lead density. <\/p>\n![\"a](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/09\/Packard-Gramsatchalkboard-1024x585.jpg\")
Leah Packard-Grams, a graduate student in archaeology who is translating papyri from Tebtunis, Egypt, discusses the difficulty of reading Greek text written more than 2,000 years ago. The word egrapsas, or \u2018you wrote,\u2019 is harder to read in ancient script (top) than modern Greek.<\/p>\n![\"a](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/09\/unrolledscroll-768x1024.jpg\")
Seiler purchased a papyrus scroll and had friends write on it in lead-spiked black ink, simulating how ancient Romans wrote. He later carbonized the scroll and was able to read the text after his colleagues X-rayed and virtually unrolled it.<\/p>\n![\"a](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/09\/LaMannaNIST-crop-1024x595.jpg\")
NIST physicist Jacob LaManna preparing to capture an X-ray CT scan of a modern-day carbonized scroll.<\/p>\n![\"gray](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/09\/scroll-comparision.jpg\")
The contemporary carbonized scroll created by Seiler and his team (top) is about 4.5 inches long. At bottom is a real scroll from the Herculaneum library as it is being scanned.<\/p>\n
![\"gold](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/09\/xrayscan-crop-1024x731.jpg\")
A full virtual unrolling of a model scroll and a closeup highlighting visible text.<\/p>\n