Reading the unreadable

Posted by Thomas Anderson

Pioneering X-ray technology is making it possible to read fragile rolled-up historical documents for the first time in centuries.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. The new technology, however, eliminates the need to do so by enabling parchment to be unrolled or unfolded ‘virtually’ and the contents displayed on a computer screen.

Developed at Cardiff University and Queen Mary, University of London with funding from the Engineering and Physical Sciences Research Council (EPSRC), the breakthrough means historians will be able to access previously unusable written sources and gain new insight into the past.

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 medieval legal scroll provided by the Norfolk Record Office.

In a completely innovative approach to the problem, 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.