Groundbreaking x-ray technique unravels secrets
19th century parchment
Pioneering x-ray technology has made it possible to read fragile rolled-up historical documents for the first time in centuries.
Old parchment is often extremely dry and liable to crack and crumble if any attempt is made to physically unroll or unfold it. But the new technology displays the contents of the unrolled scrolls on a computer screen.
No other technique developed anywhere in the world has the capability to make text concealed in rolled or folded historical parchments genuinely legible. The system has now been tested successfully on a 19th century legal scroll provided by the Norfolk Record Office.
The technique works by scanning parchment with x-rays in order to detect the presence of iron contained in ‘iron gall ink’ – the most commonly used ink in Europe between the 12th and 19th centuries.
Using a method called microtomography, a 3-dimensional ‘map’ showing the ink’s exact location is built up by creating images made from a series of x-ray slices taken through the parchment.
Advanced software specially developed by the project team combines the data obtained with information about the way the parchment is rolled or folded up and calculates exactly where the ink sits on the parchment. An image of the document as it would appear unrolled or unfolded can then be produced.
The scanning takes place at the Institute of Dentistry at Queen Mary, University of London led by Dr Graham Davis: "Because no commercial or research x-ray tomography scanners were capable of providing the quality of image we needed, we’ve developed our own advanced scanner which is also being adapted for a diverse range of other scientific uses, including those within our own Institute of Dentistry where enhanced, high contrast images are enabling the detection and analysis of features in teeth that we haven’t been able to see before."
The Cardiff team worked with colleagues at Queen Mary, University of London and the Engineering and Physical Sciences Research Council (EPSRC); the project received just under £1.3M funding. Watch to the audio slideshow to find out more.