Ancient scrolls to be virtually unwrapped

Editorial

Rebecca Pool

Thursday, October 3, 2019 - 14:30
Image: UK synchrotron set to reveal the elusive contents of 2000-year-old papyri.
 
Researchers led by renowned ancient artefacts decoder, Professor Brent Seales, will be using Diamond, the UK’s national synchrotron science facility, to examine a collection of world-famous ancient artefacts owned by the Institut de France.
 
Using this powerful light source and additional methods, the researchers are working to virtually unwrap two complete scrolls and four fragments from the damaged Herculaneum scrolls.
 
Buried and carbonized by the deadly eruption of Mount Vesuvius in 79 AD, the scrolls are too fragile to be opened.
 
However, after decades of effort, Seales reckons the scans from Diamond represent his team’s best chance yet to reveal the elusive contents of these 2000-year-old papyri.   
 
According to Seales, also director of the Digital Restoration Initiative at the University of Kentucky, a research program dedicated to the development of software tools that enable the recovery of fragile, unreadable texts: “Diamond Light Source is an absolutely crucial element in our long-term plan to reveal the writing from damaged materials.”
 
“The scan session promises to be a key moment in our quest for a reliable pathway to reading the invisible library,” he adds.
 
Over the past two decades, Seales and colleagues have worked to digitally restore and read the vast amount of material in the “invisible library” of irreparably damaged manuscripts.
 
In 2015 they achieved singular success when they visualized the never-before and never-to-be-seen writing trapped inside five complete wraps of the ancient Hebrew scroll from En Gedi.
 
For the first time ever, a complete text from an object so severely damaged that it could never be opened physically was digitally retrieved and recreated, representing a true technical breakthrough.
 
Searles now intends to deploy his so-called virtual unwrapping software pipeline - a machine learning algorithm to visualise carbon ink - to the data collected at Diamond.
 
Ancient artefacts decoder, Professor Brent Seales.
 
As Searles points out, the use of carbon ink is one of the main reasons these scrolls have evaded deciphering.
 
Unlike metal-based inks, such as the iron gall used to write medieval documents, carbon ink has a density similar to that of the carbonized papyrus on which it sits, and so appears invisible in X-ray scans. 
 
“We do not expect to immediately see the text from the upcoming scans, but they will provide the crucial building blocks for enabling that visualization,” says Searles. “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.”
 
“In addition, we believe strongly - and contrary to conventional wisdom - that tomography does indeed capture subtle, non-density-based evidence of ink, even when it is invisible to the naked eye in the scan data,” he adds.
 
According to the researcher, his machine learning tool will amplify the ink signal by training a computer algorithm to recognize it–pixel by pixel–from photographs of opened fragments that show exactly where the ink is—voxel by voxel—in the corresponding tomographic data of the fragments. 
 
“The tool can then be deployed on data from the still-rolled scrolls, identify the hidden ink, and make it more prominently visible to any reader,” he says.
 
Analysis will take place at Diamond's I12 beamline, a high energy X-ray beamline for imaging, diffraction and scattering, which operates at photon energies of 53-150 keV.
 
“This is the first time an intact scroll has been scanned in such detail at Diamond Light Source,” says Principle Beamline Scientist, Dr Thomas Connolley. “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.”
 
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