Beowulf on a CD-rom

Chris Fletcher, curator of modern literary manuscripts at the British Library, uses technology to preserve and analyse original sources, enabling a 10th-century text to be viewed worldwide

Iam one of a team of curators at the British Library responsible for acquiring, interpreting and preserving literary manuscripts. Some of my duties involve looking at documents very closely. This is where various hi-tech devices come in.

When I look at a manuscript offered to us for an opinion, or one to acquire, I need to establish if it is the real thing. There are a notorious number of facsimile Byron letters floating about, for example. A facsimile is a very high-quality printed reproduction of a letter - a bit like a sophisticated photocopy. A practised eye can discriminate between a printed or genuine manuscript, but occasionally, if someone needs convincing, I will use a "lupe", a device that is like a very powerful magnifying glass. This will reveal markings characteristic of printing.

Sometimes, however, we have to use a more sophisticated piece of equipment. Occasionally, a manuscript has, at some stage, had words scored out. There is a machine with a camera attached and various filters and lights, which allows different wavelengths reflected from the inks on the page to be recognised. Every colour responds in a different way to a different kind of light or filter, allowing one to screen out one pigment and focus upon another. Imagine writing a telephone number in blue biro and then getting a marker pen to score it out. If that were put under this machine and you experimented with, for example, ultraviolet or infrared light, you might eliminate the black and see the blue underneath.

Ultraviolet light on its own is useful for looking at watermarks, erasures or faint pencil. If a letter is dated, say, around 1821, and its watermark says 1826, we can determine that something is obviously not right.

One fascinating piece of equipment that I've used is an ESDA machine - though we don't have one at the British Library. We have a diary by TE Lawrence chronicling crucial aspects of his activities in the desert. One particular page, however, was torn out by Lawrence himself. I went to a police forensic lab and used the ESDA machine that can detect impressions on a paper.

If you had written a phone number on a pad and ripped off the top piece of paper that you wrote on, the machine might be able to detect the impressions made on the page underneath. You stretch a piece of cellophane-like material across the pages and then charge up its surface. Very fine granules of a special substance are then sprinkled across it. If you're lucky, the different charges in the impressions on the paper will reveal the original text. I have to say, though, that in this particular case absolutely nothing could be worked out.

These are all things I've used, though I have to say that the slide viewer and the humble pencil, the simplest pieces of technology, are those which I use most frequently. The library has a state-of-the-art conservation studio where every manuscript is checked, where they build individual Perspex stands to support every single item on show, where they fumigate and air manuscripts and check there's nothing in the atmosphere to damage them.

Another important development for the library has been digitisation. Here, a well-established technology - good old-fashioned pen and ink - meets a very hi-tech process. For example, the library has a unique 10th century manuscript of Beowulf. This has been photographed using sophisticated techniques and put on a CD-rom, providing scholars worldwide with an invaluable tool. People often talk about digitisation replacing manuscripts, but they will both exist side by side. It'll just give the viewer another medium to use.