A Berkeley SETI affiliate burned his own scrolls to test X-ray reading against known text

Lead absorbs up to 25 times as many X-rays as the charred papyrus around it ^[4]. A tomographic reconstruction has only that difference in absorption to work from. Carbon ink on a carbonized sheet gives it very little: "They're having problems reading a lot of them because of the low contrast of carbon ink on carbon paper," Seiler said of the Herculaneum scrolls ^[6].

The replicas are the control. A scroll from the Villa of the Papyri offers no answer key, so a reconstruction that yields plausible Greek cannot be scored; a modern roll burned to a crisp in a laboratory furnace can be checked letter by letter against what the students wrote before it went into the heat ^[2][1].

Seiler's stated hypothesis had two parts: that leaded ink would stand out under an X-ray beam, and that computer algorithms could then virtually unroll the scroll ^[15]. The published account covers the first part. It does not describe the burned replicas being used to train or validate reading software ^[3].

How much of the library this reaches depends on how many ancient scribes used leaded ink, and no one has systematically looked ^[10]. One researcher found lead in the ink of a fragment left over from the early physical unrolling attempts ^[10]. The collection runs to roughly 1,800 scrolls and fragments, held in Italy, France and England, with that one confirmed detection among them ^[13][18]. If most of the library was inked with plain carbon, the 25-to-1 contrast never appears ^[4].

The reason anyone burns good Egyptian papyrus to find out is in the record of the failures. Physical unrolling began after the scrolls were found in 1752, mostly produced heaps of ashes, and was halted by Italian authorities ^[11]. What did come apart legibly was new: every physically unrolled scroll has held text unknown to scholars, much of it by the Epicurean philosopher Philodemus, who lived in Herculaneum a century before Vesuvius buried it ^[12]. The eruption left the only known intact library from antiquity ^[16]. "The stakes are the largest in the history of Greek literature," said Leah Packard-Grams, the Berkeley archaeology graduate student who consulted on the project as a papyrologist ^[14].

"We're 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," Seiler said ^[7]. The searching would happen on objects in three countries' collections, 274 years after the scrolls came out of the ground ^[13][17].