An unexpected discovery has brought to light a new X-ray imaging technique that researchers applied to Rembrandt’s masterpiece Night Patrol. The results of the research are published in the journal “Science Advances”.

The survey found a hitherto unknown layer of lead on the canvaswhich scientists believe Rembrandt used to protect the painting from moisture, rather than the standard method of the time by applying a layer of glue.

The Night Watch, Rembrandt’s most famous work, was completed in 1642 and is on display at the Rijksumuseum in Amsterdam. It is one of the most famous paintings of the Golden Age of Dutch painting.

The large-scale painting depicts Captain Frans Bannink Coke ordering his guards out to protect their city. The work impresses for the dramatic contrasts the artist uses between light and shadow to highlight the most important characters in the scene. Although it was previously believed that the scene he was capturing was a night scene, it was later found that the build-up of dirt and varnish was the cause of his darkness.

The great changes the painting has undergone over the centuries led the Rijksmuseum to decide to launch ‘Operation Night Patrol’ in 2019, a multi-year research and conservation project that explores how Rembrandt created the work, as well as its current state, using a variety of imaging and computational techniques. Understanding the above parameters is important for scientists to proceed with the maintenance of the painting with the best possible technique that will ensure its long-term preservation.

In the context of the above investigations, the preparatory layers of the painting were found in focus. Earlier, white specks were found in various parts of the painting, which were found to be projections of lead.

The research team collected a small fragment of paint from the painting and studied it with a new method, which combines X-ray fluorescence techniques with X-ray nanotomography, to identify and visualize smaller-scale chemical elements in the lower layers of the canvas.

As Frederique Broers explains to APE-MPE, elead author of the publication and researcher at the Universities of Amsterdam, Antwerp and Utrecht and the Rijksumuseum, it is a technique that has not been applied before in the study of paintings and which ensures the investigation of all three dimensions of the painting and the particles of color that make it up.

Using this technique, the researchers discovered that beneath the ground layer of quartz and clay on the canvas, there is a layer rich in lead. “This find shows us that Rembrandt was not afraid to try new techniques,” observes Ms Broers. “The painting was so large in dimensions that the painter could not use the usual methods, so he looked for alternatives and we believe that he used lead to protect the painting from moisture,” he adds.

It is known to researchers that in the 17th century lead was used to protect objects from wood, stone and metal. In a book of the time, Theodore De Mayerne advised painters how to prepare the canvas with animal glue, and in a footnote suggested the use of oil containing lead to protect paintings hung on the wall from moisture. So it seems that the method of impregnating a canvas with oil containing lead was known, although not widely used.