Lead Base Layer Discovered in Rembrandt’s ‘The Night Watch’

The Dutch painter Rembrandt covered the surface of his canvas with a substance that contained lead before he began painting his 1642 masterpiece The Night Watch, according to new research.

Using X-ray imaging techniques, scientists have discovered a previously unknown lead base layer beneath the paint. These findings, published last week in the journal Science Advances, add to the art world’s understanding of one of Rembrandt’s most famous works. They could help conservationists better preserve the piece moving forward.

Rembrandt, who lived from 1606 to 1669, is widely considered “the greatest artist of Holland’s ‘Golden Age.’” He was especially adept at using light and shadow in his works.

The Night Watch’s full title is Militia Company of District II under the Command of Captain Frans Banninck Cocq. Today, it’s on display at the Rijksmuseum in Amsterdam.

The roughly 12- by 14-foot painting depicts a group of civilian soldiers—called the civic guard—preparing to protect Amsterdam from attack. In the scene, the captain, named Frans Banninck Cocq, is ordering his men to get in formation and get ready to march out. A young girl in the foreground serves as the group’s mascot.

The painting had long been thought to depict an evening scene. In reality, it’s simply covered in varnish, making it appear darker than when Rembrandt painted it.

In 2019, the Rijksmuseum launched Operation Nigh Watch to study the painting, hoping to learn more about the artist’s process and how best to conserve the work. Since then, researchers working on the project have used artificial intelligence to restore the painting to its full size (all four sides had been trimmed in 1715) and even discovered a hidden sketch underneath the work. The new study also stems from this project.

To investigate the painting’s chemical composition, researchers studied a tiny paint sample using techniques known as X-ray fluorescence and ptychography. That’s when they found a lead-rich layer, which was topped by a quartz-clay ground layer. (A ground layer helps prepare the canvas, and its “color and tone can affect the chromatic and tonal values of the paint layers applied over it,” according to the National Gallery in London.)

Based on the distribution of lead across the painting, researchers suspect Rembrandt applied a lead-containing oil using large, semi-circular brushstrokes. They also think he completed this step immediately after the canvas was stretched.

Why, though, would Rembrandt coat the canvas in a lead-rich substance? One theory is that he wanted to protect it from humidity, write the researchers. He knew the painting would be hung on an exterior wall at Kloveniersdoelen, a musketeers shooting range in Amsterdam, where it would be exposed to the elements.

Past research has found that Rembrandt used a pigment called lead white in some of his paintings, including The Night Watch (as did Leonardo da Vinci more than a century earlier). But this is the first time researchers have discovered a lead base layer in any works created by Rembrandt or his contemporaries, per a statement.

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.