Visualizing and Quantifying Rembrandt’s Smalt Mixtures in The Night Watch in Three Dimensions Using μ‑X-ray Fluorescence Tomography

The heterogeneity is very high among the particles within one paint sample. Different clusters of particles can be established based on the intensity of bismuth. This variety could be caused by heterogeneity in the cobalt ore, the glass-making process, the use of multiple types of smalt or it might be the result of <i>in-situ</i> degradation.

Next to the smalt, the volume percentages taken up by other components of the paint are semi quantitively estimated based on elemental information. This information can be used in follow-up studies to improve the accuracy of models and the representativeness of reconstructed paint mockup samples. SR-μ-XRF tomography proves to be a valuable tool for the identification and quantification of complex heterogenous smalt paints.