At the National Library of Finland, medieval manuscripts are usually studied with the eyes and the mind. In CHARM, we add another sense to the mix: X-rays.
Using a portable X-ray fluorescence (XRF) instrument, we analyse pigments and inks directly on manuscripts and fragments, without taking samples or harming the material. XRF allows us to detect chemical elements present on the surface of parchment, such as iron (Fe), copper (Cu), or lead (Pb). These elements act as clues, pointing us toward the materials medieval scribes and artists once used.
For example, if copper shows up strongly in a blue area, azurite becomes a likely candidate. But heritage science is rarely that simple. Copper does not automatically mean azurite, and the absence of copper does not rule it out either. Pigments can be mixed, degraded, or applied in ways that complicate the picture.
These measurements wrap up our data collection from all the hundreds of manuscript fragments and medieval charters! Thank you to Henni Reijonen, Jukkapekka Etäsalo, and especially Eero Ehanti from the Finnish Heritage Agency for this collaboration, and yet again for the National Library of Finland for opening its doors for our research.