FRANCE – Herculaneum papyri found in the eighteenth century were buried by lava after the Mount Vesuvius erupted causing a swilling that destroyed the Roman cities of Pompeii and Herculaneum in 79 AD. Two thousand manuscripts were reduced to a mass of charred and brittle documents.  To date, all attempts to decipher its contents had caused significant damage to the papyri, if not causing total destruction.

Scientists at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) used a synchrotron accelerator to generate beams X-ray beam one hundred billion times more intense than those used in any modern- hospital to study the manuscripts. They made a surprising discovery: the manuscripts were written with metallic ink.

The extraordinary thing about this finding is that hitherto held by the academic community, based on the work of the Roman historian Pliny the Elder, is that ink made from charcoal remains extracted from wood stoves was used. Pliny was one of the victims of the Vesuvius eruption.

The only identified use of metallic ink prior to this era was for writing secret messages in the second century BC.  From approximately 420 AD, a metal iron gall blend was prepared and used as a new writing ink for parchment. Subsequently, the standard for the scrolls of late relic and throughout most of the Middle Ages was metallic inks.

In January 2015, the researchers used the accelerator to try to identify letters of the Greek alphabet, and even whole words in texts.  Later, they learned that papyrus scrolls containing high concentrations of lead that could only be explained by its intended use as a component of the ink.

Scientists came to this conclusion after finding that metal levels detected were too high to be caused by contact with water contaminated by lead pipes used by the Romans, with inkwells copper or bronze kits.

Emmanuel Brun of the ESRF said that they found traces of lead-something metal in the ink, presumably such advancement had not taken place until four centuries later [the eruption of Vesuvius] adding that “it was believed that the Romans had introduced the metallic ink in the fourth century.”

These findings, published in the journal Proceedings of the National Academy of Sciences (PNA) , shed new light on the technologies of the ink and paper used in the grandeur era of the Roman Empire, and not leave any doubt that the metal ink was invented several centuries earlier than previously thought.

New keys

Scholars in the field are now able to  investigate the writing techniques used in antiquity and try to read texts of the time that were thought unrecoverable.  They may try to decode unfamiliar texts that they had access previously.

“This discovery has great significance for historians, but also for those who are dedicated to obtain X-ray images of the scrolls,” Brun said.  “The different phases of this study will allow us to improve ink in the next experiments to decipher the invisible text of the papyri” through a better choice of imaging technique used and the selected wavelengths.

Marine Cotte, scientist in charge of ID21 beamline, used in the experiment, explained  that “This type of experiment demonstrates the importance of imaging techniques in the analysis of cultural heritage objects. Thanks to the ESRF’s powerful X-rays, the analysis can be carried out very quickly (a tenth of a second per point), allowing us to acquire large amounts of data very quickly. We were able to sweep all the samples and be sure of the correlation between the chemical information and the visible trace of the letters. Another advantage of using the synchrotron is that we could easily combine a low-resolution study (analysis of all the letters with a beam measuring one tenth of a millimetre) with a high-resolution study (this time using a beam smaller than one thousandth of a millimetre, a micron) to try to discover the secret of the composition of the ink and see which elements were associated with lead.”

Of the two thousand volumes extracted from Herculaneum, about six hundred remain intact.  Most are philosophical works written in ancient Greek, but among them written in Latin.

Thanks to these findings and improvement of radiological innovative techniques used in the context of this study, perhaps soon they can decipher the rest of manuscripts and greatly expand our knowledge of the culture, literature and lifestyles characteristic of Classical Antiquity.