The Book of Kells: A non-invasive MOLAB investigation by complementary spectroscopic techniques

- The Book of Kells is assessed by non-invasive in situ portable spectroscopy.
- Complementary techniques highlight the intentional use of anhydrite.
- Rare identification of the organic lichen dye, orchil in a manuscript.
- Alteration of organic black giving rise to calcium carboxylate and calcium oxalate.