Multi-spectral Imaging at the British Library

The British Library is the national library of the United Kingdom and holds over 150 million items with an additional three million new items added each year. The 625 km of shelving contains manuscripts, maps, newspapers, magazines, prints, drawings, music scores and patents. The fundamental purpose of the Library is to make intellectual heritage accessible to everyone, for research, inspiration and enjoyment. It is therefore imperative that these texts are legible. Three instances of text illegibility were identified as requiring technological help beyond traditional digitization; (i) Fire-damage rendering text and illuminations charred and sometimes shrunken or skewed, (ii) Indistinct areas of text which have either degraded naturally or been purposefully erased, and (iii) Chemical damage usually as a consequence of historical treatments to recover faded text, evidenced by reams of discolored and stained folios. The sheer variety of materials and implements used for writing and drawing, combined with varying degrees of an item's condition, presents difficulties in optimally imaging these items for legibility. In 2013, a new role of Conservation Research Imaging Scientist was created to develop strategies and solutions to overcome these challenges. Multi-spectral imaging was subsequently adopted by the Library and has proven to be an invaluable aid to scholars and researchers. Combined with post-processing imaging techniques such as Principal Component Analysis and Color Space Analysis, multispectral imaging has delivered spectacular results. Future work aims to integrate techniques such as Reflectance Transformation Imaging while ensuring improved access to scientific datasets to complement existing digital collections.