A pair of 2,000-year-old Roman scrolls which were charred in the eruption of Mount Vesuvius are finally being deciphered using light brighter than the sun.
When the volcano blast wiped out Pompeii in 79AD, hundreds of texts from the Herculaneum library were buried and carbonised by the smoking ash and gases.
They resurfaced in 1752 in a villa near the Bay of Naples believed to belong to the family of Julius Caesar, but their contents have remained a mystery as scientists judged them too fragile to unfurl.
But after decades of effort, a British team with cutting-edge technology is using light more powerful than the sun to read the scrolls for the first time.
Diamond Light Source, a science facility in the UK, scanned a collection of the Herculaneum scrolls owned by the Institut de France.
By scanning fragments previously peeled off by the Institut de France, the scientists hope to create a machine-learning algorithm that will decipher what is written on the furled scrolls.
Laurent Chapon, physical science director of Diamond Light Source, said: ‘The idea is essentially like a CT scanner where you would take an image of a person, a three-dimensional image of a person and you can slice through it to see the different organs.’
‘We… shine very intense light through (the scroll) and then detect on the other side a number of two-dimensional images.
‘From that we reconstruct a three-dimensional volume of the object… to actually read the text in a non-destructive manner.’
The ink on the scrolls is difficult to see, even through a synchrotron, because it is carbon-based like the papyrus it is written on.
But scientists hope the density of the paper will be different where written characters are present.
Artefacts decoder Professor Brent Seales thinks the scans represent his team’s best chance yet to reveal the elusive contents of the ancient papyri.
Prof Seales, director of the Digital Restoration Initiative at the University of Kentucky, said: ‘Diamond Light Source is an absolutely crucial element in our long-term plan to reveal the writing from damaged materials, as it offers unparalleled brightness and control for the images we can create, plus access to a brain trust of scientists who understand our challenges and are eager to help us succeed.
‘Texts from the ancient world are rare and precious, and they simply cannot be revealed through any other known process.’
The majority of the 1,800 scrolls reside at the Biblioteca Nazionale di Napoli, although a few were offered as gifts to dignitaries by the King of Naples and wound up at the Bodleian Library at Oxford University, the British Library, and the Institut de France.
Last May, Prof Seales and a small team examined the two completely intact scrolls, along with four small fragments from scrolls unrolled in the late 1800s at Institut de France.
The four fragments contain many layers and feature visible, exposed writing on the top, which will provide key data needed to develop the next iteration of the team’s ‘virtual unwrapping’ software pipeline.
This is an algorithm that will enable the visualisation of carbon ink.
Prof Seales says the use of carbon ink is one of the main reasons these scrolls have evaded deciphering.
Unlike metal-based inks, its density is similar to that of the carbonised papyrus on which it sits, and therefore appears invisible in x-rays.
Prof Seales said: ‘We do not expect to immediately see the text from the upcoming scans, but they will provide the crucial building blocks for enabling that visualisation.
‘First, we will immediately see the internal structure of the scrolls in more definition than has ever been possible, and we need that level of detail to ferret out the highly compressed layers on which the text sits.’
The technology amplifies the ink signal recognising exactly where the ink is using photographs of opened fragments.
It can then be used on data from the still-rolled scrolls, identify the hidden ink, and make it more prominently visible to any reader, Prof Seales explained.
The I12 beamline or JEEP (Joint Engineering, Environmental, and Processing) beamline, at Diamond is a high energy X-ray beamline for imaging, diffraction and scattering.
Dr Thomas Connolley, the principle Beamline scientist, added: ‘We are very excited to work with the research team, playing our part in what we hope will be a major step forward in unlocking the secrets that the scrolls contain.’
