Unveiling Hidden Secrets in Rembrandt's "Night Watch"
Recent discoveries have uncovered more than meets the eye in the famous painting "Night Watch" by Rembrandt.
When conservators at the Rijksmuseum examined the painting with X-rays and spectral analysis, they found something unexpected beneath the surface: a lead-filled layer. This marks the first time that Röntgen rays, combined with spectral analysis and 3D reconstruction, have been used to uncover previously unknown quantities of rich lead in Rembrandt's works. Study authors shared their findings in the journal Science Advances on Friday.
In the typical painting process of Rembrandt's time, artists would first apply a layer of hardened glue to the canvas and then add a ground layer composed of pigments gently worked into the lower layers of the canvas. However, "Night Watch" is an exception. Instead of a layers of glue, Rembrandt might have used a lead-infused layer to better protect the canvas.
The painting was finished in 1642 and hung in a room facing a window at the Amsterdamer Kloveniersdoelen (Musketeers' shooting gallery) where it was exposed to moisture damage.
Frédérique Broers, the study's primary author and a researcher in microscopy at the Rijksmuseum, suggested that Rembrandt may have learned the idea of using lead in canvas preservation from a medical publication. This pamphlet, written by a physician based in Geneva named Théodore de Mayerne, detailed the chemical process by which paint could degrade when exposed to moisture. In Amsterdam, "Night Watch" can be viewed.
Mayerne's book mentioned a painted work, where the paint and glue layers separated due to decay after many years of being exposed to moisture. In this case, the canvas required a base made of oil containing lead. Broers noted to CNN that researchers believe Rembrandt chose the lead solution due to its stronger drying properties in comparison to traditional glue preparations.
Broers pointed out that regardless of the inspiration—whether it came from Mayerne's text or conversations among artists—Rembrandt might have employed this unique technique as a means of refining the painting. Given that the painting was to be displayed in an environment prone to moisture damage, this protective layer proved a valuable asset.
These findings reveal Rembrandt's openness to unconventional methods in pursuit of his unique artistic vision, setting it apart from his standard practice.
Operation Mahnwache
The researchers' detective work forms part of the "Operation Vigil" project launched by the Rijksmuseum in 2019. The original title of the painting was "Militia Company of District II under Captain Fran Frans Bannink Cock," which was later altered partially due to its thick varnish layers and the effects of time to "Night" and "Watch."
The varnish on the painting darkened over time, leading viewers to believe the scene took place at night. During cleaning efforts in the 1940s, several varnish layers were removed, thereby reducing some of the darkness. However, further restoration and analysis are required for the painting.
The "Operation Vigil" project combines large-scale scans of the painting using multiple technologies, including Röntgen fluorescence, powder diffraction, and reflectance spectroscopy. These cutting-edge methods produce visualizations of chemical elements and molecules, which display their distribution and reveal crystal structures.
Broers explained that by extracting a minuscule paint sample—just 0.002 inches (55 micrometers) wide and 0.006 inches (160 micrometers) long—from the painting, scanning it, and then creating a 3D digital model, new insight can be gained into the composition of the painting.
"Normally, one imagines a painting as a 2D object, but in reality, it is a 3D object due to its layers of pigment," explained Broers. Studying 3D objects demands a 3D perspective, "[enabling us] to truly understand the size of particles and the relationship between different pigment particles."
The Secret of the "Beulen"
For decades, experts have pondered the appearance of tiny "beulen" (blisters) containing lead crystals scattered across the entire painting. The presence of lead in pigments is common, but the low use of white lead paint in "Night Watch" is strange since the painting lacks significant white areas.
Browers noted that even in the darkest sections, minuscule lead flecks had appeared, intensifying the mystery. Ultimately, the secret of the "beulen" was discovered with the identification of the lead-infused layer covering the canvas.
"Knowing the current state of the paint is a great challenge," noted Browers. Eighteenth-century publications, including one by Théodore de Mayerne, had described how the breakdown of certain paint compositions resulted from prolonged exposure to moisture. During earlier examinations, the composition of the layer lying on top of the lead layer was discovered to consist of quartz and clay—the earliest evidence that Rembrandt used this mixture throughout his career.
Rembrandt applied two layers of ground preparation to the canvas for earlier works: one with red clay and another with white pigment. However, Night Watch is significantly larger than Rembrandt's other paintings, with dimensions of 12.5 feet (3,800 mm) high and 14.9 feet (4,500 mm) wide. Research has indicated that monolayers–a single layer of paint–are lighter, more flexible, and cost-effective compared to the traditional two-layer preparations.
Browers added that the success of "Night Watch" is due to a multi-disciplinary approach to preservation and restoration. The data from the Röntgen scans were combined with the findings from cleaning and conserving experts, while the curator's interpretation provided historical context for the chemical components incorporated into the paint and ground layers. The collaboration of various fields brought Night Watch into the modern age and continues to captivate generations of art enthusiasts.
"This entire field of expertise from the Night Watch team is essential for fully integrating these findings into the actual situation," said Broers.
Mindy Weisberger contributes to Live Science, Scientific American, and How It Works as a science writer and media producer.
