Chemists reveal how Rembrandt combined special pigments for golden details of 'The Night Watch'
Chemists at the Rijksmuseum and the University of Amsterdam (UvA) have for the first time established how Rembrandt applied special arsenic sulfide pigments to create a "golden" paint.
Using sophisticated spectroscopic techniques, they were able to map the presence of pararealgar (yellow) and semi-amorphous pararealgar (orange/red) pigments in a striking detail of his famous work "The Night Watch." Corroborated by study of related historical sources, they conclude that Rembrandt intentionally combined these particular arsenic sulfide pigments with other pigments to create the golden luster.
The discovery was published in the journal Heritage Science by Fréderique Broers and Nouchka de Keyser, Ph.D. candidates at the UvA's Van 't Hoff Institute for Molecular Sciences and researchers at the Rijksmuseum.
They conclude that Rembrandt used the rather unusual combination of pigments to depict the golden threading in the doublet sleeves and embroidered buff coat worn by Lieutenant Willem van Ruytenburch. He is on the right of the two central figures at the front of the shooting company tableau, accompanying Captain Frans Banninck Cocq.
Unusual pigments
The discovery of the arsenic sulfide pigments took place in the large-scale research project Operation Night Watch which started in 2019 and continues to deliver striking results. A full X-ray fluorescence (MA-XRF) scan of the painting had already revealed the presence of arsenic and sulfur in parts of Van Ruytenburch's clothing. It led the researchers to assume the presence of the well-known arsenic sulfide pigments orpiment (yellow) and realgar (red).
Cross section of paint sample SK-C-5_017 as seen through a light microscope. It shows various crystals of yellow, orange and red pigments of which the precise composition was established using a combination of electron microscopy, Raman spectroscopy, and X-ray powder diffraction. Credit: Rijksmuseum.
Rembrandt’s Night Watch (left), the clothing of Lieutenant Willem van Ruytenburch (right) and the location where paint sample SK-C-5_017 was taken. Credit: Rijksmuseum