Multi-spectral imaging
The British Library has bought a MuSIS multi-spectral imaging camera to help reveal details of manuscripts that are invisible to the naked eye, such as faded or deliberately erased text and over-writing.
Essentially, MuSIS is a high-resolution digital camera which can take pictures at 32 different wavelengths, ranging from the ultra-violet to the near infra-red. MuSIS can measure the reflectance spectra of inks or pigments at any point, which enables them to be identified or distinguished from one another.
MuSIS was developed by FORTH Photonics in Athens, originally for medical imaging in cancer diagnosis, but it has since found many applications in art history.
MuSIS also comes with software that can help in the examination of palimpsests. These are manuscripts on parchment that has been washed or scraped to remove the writing so that it can be re-used. Sometimes traces of the original writing remain, which can be deciphered. Using similar equipment, the Walters Art Gallery in Baltimore has been able to recover the text of a lost work by Archimedes, which was re-used for a prayer book in the thirteenth century. Other palimpsests exist in the British Library’s collections, and we hope that MuSIS may be similarly useful for examining them.
