X-Rays Unlock Ancient Scrolls

A team of European researchers have used the latest X-ray technology to unlock ancient texts. Stacks of scrolls were preserved by gas and ash when Mount Vesuvius erupted in 79 AD, burying ancient Pompeii and a library in the nearby town of Herculaneum. There have been many attempts to read the texts since they were discovered 260 years ago, but the carbonized scrolls are extremely fragile and have often been damaged or destroyed in previous attempts. Some of the more successful approaches have involved using binocular microscopes and digital photography. However, they don’t work for the many texts that are stuck rolled up.

The scrolls were written in carbon-based ink on sheets made from stalks of the papyrus plant. Therefore, the composition of the ink and plant-based “paper” are too similar for traditional X-ray computed tomography (XCT) techniques to work. However, phase-contrast imaging has rapidly improved in the past 15 years, and with X-ray phase-contrast tomogrpaphy (XPCT), X-rays are not only absorbed when passing through matter, but also refracted. This means that XPCT can distinguish different materials of similar composition within a single object, just like the charcoal ink on carbonized papyrus.

The researchers used XPCT at the European Synchrotron, an X-ray light source located in Grenoble, France. They used this new technique to decipher letters of the Greek alphabet on the scrolls. The details of the process and results of the findings are published in Nature Communications journal this month. Computer scientists are currently working on programming that will help distinguish which letters belong to each layer of the rolled up scrolls. The new imaging technique unlocks the preserved scrolls and enhances our knowledge of ancient Greek literature and philosophy.

This work proves, once again, the extremely high efficiency of Phase Contrast Imaging. Now we just have to face the analysis of this huge volume of data.

Author Emmanuel Brun
Source: Nature | ESRF | Image by J. Delattre