Since July 2019, “Operation Night Watch” has been ongoing at the Rijksmuseum Amsterdam, the aim of which is the thorough investigation and subsequent restoration of Rembrandt’s famous masterpiece. Protected by a glass case, the work is carried out in front of the visitors to the museum, which houses the world's largest collection of Rembrandt works.
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So far, non-invasive procedures have been used in the investigations and extremely high-resolution photography has also been taken, which makes the smallest details such as individual particles and brush strokes visible to the naked eye.
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But of course not all investigations can be carried out in the Rijksmuseum itself. A microscopic sample of the painting was sent to the German Electron Synchrotron (DESY) in Hamburg, where it was closely examined using the PETRA III X-ray source. It turned out that under the already known quartz-clay primer there is still a lead-containing impregnation layer, which has not yet been found in any other painting by Rembrandt or one of his contemporaries, although we know from written sources that this method was at least used at the time.
The research team, which published its latest findings in the journal Science Advances, assumes that Rembrandt used this lead-containing primer to protect his paintings from moisture. The Night Watch, completed in 1642, was intended for an outer wall of the banquet hall of the rifle guilds in Kloveniersdoelen, Amsterdam. Rembrandt undoubtedly knew about the exact location where it would be hung; after all, one doesn't paint a 12 x 14 ft (originally even 12.4 x 14.8 ft) painting without first clarifying whether it can actually be installed at its intended location.
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A primer containing lead white, which has an accelerating drying effect, is known from Rembrandt's earlier works, but the lead-containing primer required for the large-format Night Watch is probably a cheaper and lighter alternative. Nevertheless, the painting weighs an impressive 375 pounds, so The Night Watch can be described as a heavyweight in art history - both in the actual and figurative sense.
