The use of XRF imaging for the chemical discrimination of iron‐gall ink inscriptions: A case study in Stradivari's workshop

X‐ray fluorescence (XRF) analysis is a powerful approach to discriminate iron‐gall inks from different inscriptions. The representativeness of spot measurements is though often impaired by the material history and conservation state of historical artefacts bearing such inscriptions. The method proposed here, using a XRF scanner, not only improved the readability of inscriptions, thanks to the enhanced contrast offered by chemical maps, but also allowed the evaluation of iron, copper and zinc contents of the inks, by the optimised selection in MA‐XRF maps of more than 1,000 spectra from each inked area, representing an equivalent analytical surface of several square‐millimetres. In addition, the quantitative calibration of the system based on the thin target approximation allowed calculating these elements concentration. This method, applied to a series of ink inscriptions on a set of artefacts from Stradivari's workshop (active from 1666 to 1743) now in the collection of the Musée de la musique (Paris, France), offers a complementary route to the more conventional palaeography‐ and graphology‐based approaches for the potential identification of the authors of the inscriptions.