By Liz Seward
Science reporter, York
The hidden content in ancient works could be illuminated by a light source 10 billion times brighter than the Sun.
The technique employs Britain's new facility, the Diamond synchrotron, and could be used on works such as the Dead Sea Scrolls or musical scores by Bach.
Intense light beams will enable scientists to uncover the text in scrolls and books without having to open - and potentially damage - them.
The research was presented at the British Association science festival.
Iron gall ink, which is made from oak apples, has been in use from the 12th Century, but causes parchment to deteriorate rendering precious documents unreadable.
Parchment - thinly stretched skins from cows, sheep or goats - contains collagen. Collagen naturally degrades to gelatine, but iron ink speeds up this process.
When dry, gelatine is very brittle; but as soon as it gets wet, it turns into jelly, destroying some documents - especially if they are disturbed.
The ink also damages paper, sometimes completely destroying documents.
Unrolling the scroll
Now, scientists from the University of Cardiff have developed a technique that uses a powerful X-ray source to create a three-dimensional image of an iron-inked document.
The team then applies a computer algorithm to separate the image into the different layers of parchment, in effect using the program to unroll the scroll.
Professor Tim Wess, who led the research, said: "We've folded up a real piece of parchment and then done a process of X-ray tomography on it. We've been able to recover the structure where we can see the words that are written inside the document."
HOW DIAMOND WORKS
Electrons fired into straight accelerator, or linac
Boosted in small synchrotron and injected into storage ring
Magnets in large ring bend and focus electrons accelerated to near light-speeds
Energy lost emerges down beamlines as highly focused light at X-ray wavelengths
The team now plans to use the Diamond synchrotron's powerful X-ray source to penetrate many layers of parchment.
The synchrotron, which covers the area of five football pitches, generates light beams that can probe matter down to the molecular and atomic scale.
Professor Wess explained: "The letters have got iron in them, so you shine a band of X-rays through, and you end up with an absorption image, rather like your bones would absorb on an X-ray.
"This is something we can take forward with Diamond, to try to unravel the secrets inside documents that we're too scared to try to open, or that are beyond the point of conservation."
The National Archives has donated some 18th Century fire-damaged scrolls that have never been unrolled, due to their condition. But the team also has a wish-list of works that they plan to probe.
Professor Wess said: "There are some parts of the Dead Sea Scrolls which have not been unrolled."
Reading books without opening them was a goal of the project, added Professor Wess. The technique works best with rolled parchment. The flat nature, as well as the thickness of books, presents a challenge.
He said: "I know of books which have been damaged by iron gall ink corrosion where the conservators are actually afraid to open the book because of all the letters. You really end up with a stencil rather than the lettering."
Another target of the project is to image documents before they become too damaged, to monitor levels of gelatine.
The team can then advise on the most appropriate conservation methods, depending on the state of the parchment.
Using modern technology to reveal secrets of the past is a rewarding task.
Professor Wess said: "If you can bring together a £260m ($527m) synchrotron, and the cutting edge science from that, the provenance and the depth of history that you can access when you see these things is actually a revelatory moment."