Rembrandt’s most famous work contains rare chemical

By Mark Waghorn via SWNS

Rembrandt's most famous work contains a rare chemical that helped the masterpiece dry quickly, scientists have revealed.

The metallic molecule, lead formate, was identified in The Night Watch - renowned for its vast size and dramatic use of light and shadow.

Lead formate had never been found in historic art - showing the Dutch 'golden age' pioneer was years ahead of his time.

It is used in solar energy and water treatment industries today.

First author Dr. Victor Gonzalez believes it was created when yellow pigment was heated in oil.

The result was faster hardening on the canvas - making it easier to work with and improving the finish.

It may hold the key to his success.

Dr. Gonzalez, of CNRS in Paris, was stunned by the finding, saying: "In paint, lead formates have only been reported once in 2020 - but only in model mock-ups.

"Not only do we discover lead formates, but they are in areas where there is no white, yellow or lead pigment.

"We think that probably they disappear fast. This is why they were not detected in old master paintings until now."

Rembrandt painted The Night Watch in 1642. It is his largest composition, measuring a whopping 12 by 14.5 feet, and hangs in the Rijksmuseum, Amsterdam.

The work is also notable for its fostering of a sense of motion in what would otherwise have been a typical, static military group portrait.

Dr. Gonzalez's international team analyzed the materials by combining X-ray images from powerful scanners.

Prof Katrien Keune, head of science at Rijksmuseum, said it has helped them understand Rembrandt better.

She explained: "In Operation Night Watch we focus on Rembrandt's painting technique, the condition of the painting and how we can best preserve it for future generations.

"The lead formate gives us valuable new clues about the possible use of lead-based oil paint by Rembrandt and the potential impact of oil-based varnishes from past conservation treatments, and the complex chemistry of historic oil paintings."

To investigate the origin of the compound and unearth Rembrandt's workshop recipes the researchers also studied fragments taken from The Night Watch and model samples prepared in the laboratory simulating the painter's formulations.

They believe Rembrandt used linseed oil containing dissolved lead oxide to boost drying - speeding up the completion of this ambitious project.

Co-author Marine Cotte, of the European Synchrotron Radiation Facility, Grenoble, France, said: "We could map the presence of formates at a micrometric scale, and follow their formation over time."

The spatial organization of the compounds at the micro-scale and the dynamics of their formulation made it possible for the researchers to suggest new hypotheses on the chemical conditions of crystallization in old paint layers.

Added co-author Prof Koen Janssens, of the University of Antwerp: "In addition to providing information on Rembrandt's pictorial techniques, this research opens up new avenues on the reactivity of historical pigments, and therefore on the preservation of heritage."

The next step for the team is to further study the origin of these formates and see if they could also originate from past restoration treatments.

The study is in the journal Angewandte Chemie.