Correlated x-ray fluorescence and ptychographic nano-tomography on Rembrandt's <i>The Night Watch</i> reveals unknown lead "layer".

Broers, Fréderique T H; Verslype, Ige; Bossers, Koen W; Vanmeert, Frederik; Gonzalez, Victor; Garrevoet, Jan; van Loon, Annelies; van Duijn, Esther et al. · Sci Adv · 2023

basic_science · Level V

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Abstract

<i>The Night Watch</i>, one of the most famous masterpieces by Rembrandt, is the subject of a large research and conservation project. For the conservation treatment, it is of great importance to understand its current condition. Correlated nano-tomography using x-ray fluorescence and ptychography revealed a-so far unknown-lead-containing "layer", which likely acts as a protective impregnation layer applied on the canvas before the quartz-clay ground was applied. This layer might explain the presence of lead soap protrusions in areas where no other lead components are present. In addition to the three-dimensional elemental mapping, ptychography visualizes and quantifies components not detectable by hard x-ray fluorescence such as the organic fraction and quartz. The first-time use of this combination of synchrotron-based techniques on a historic paint micro-sample shows it to be an important tool to better interpret the results of noninvasive imaging techniques operating on the macroscale.