The Palette of the Medieval North

Summary

The selection of fragments contained many of those pigments already noted in the extensive analytical work conducted elsewhere in Europe7,8,9,10,11,12,13,14, such as azurite, red lead, vermilion, orpiment, and copper-based greens. Even though these fragment pages might appear rather simple in terms of their colour scheme, the analysis has shown a greater variation and complexity than first meets the eye. This observation will be further elaborated below where findings are listed by colour. A summary of the findings can be found in Table 2. Further images and XRF maps can be found in Supplementary information 2 (SI2), and 3 (SI3).Table 2 Summary of identified colourants and inks based on results from FTIR, Raman, HSI, FORS and XRFBlueAll blues, except one, were identified as azurite by HSI (absorption max 640 nm) and FTIR (a strong doublet at 4380 and 4244 cm−1, which can be attributed to both the combination of ν + δ (OH) and the overtone 3ν3. This doublet partially overlaps with the methylenic C–H stretching and bending combination from lipidic binders), and is further corroborated by the presence of copper in the XRF analysis12,22. Azurite is a basic copper (II)-carbonate: 2 CuCO3·Cu(OH)2 forming bright blue crystals. The pigment can be prepared either from naturally occurring minerals or produced synthetically. The presence of particular impurities can arguably be used to attribute origin and identify leaves that come from the same workshop23. The azurites of the pages of the investigated selection show a variation in impurities, which could indicate different geological sources or different grades of purification. They showed the presence of barium, iron, zinc, arsenic, manganese and bismuth in XRF analysis with notable variability between the various fragments (Fig. 3, Table 2). The combination of impurities can thus confirm the likeness or not of the different fragments or various leaves of the same fragment. The presence of impurities in azurite has been note...