Public area
Rembrandt’s The Night Watch, painted in 1642, is the Dutch grasp’s largest surviving portray, identified notably for its beautiful use of mild and shadow. A brand new X-ray imaging evaluation of the masterpiece has revealed an sudden lead layer, maybe utilized as a protecting measure whereas making ready the canvas, in accordance with a brand new paper printed within the journal Science Advances. The work was half of the Rijksmuseum’s ongoing Operation Night Watch, the most important multidisciplinary analysis and conservation mission for Rembrandt’s well-known portray, dedicated to its long-term preservation.
The well-known scene depicted in The Night Watch—formally known as Militia Company of District II underneath the Command of Captain Frans Banninck Cocq—was not meant to have taken place at evening. Rather, the darkish look is the outcome of the buildup of dust and polish over 4 centuries, because the portray was topic to numerous sorts of chemical and mechanical alterations.
For occasion, in 1715, The Night Watch was moved to Amsterdam’s City Hall (now the Royal Palace on Dam Square). It was too massive for the brand new location, so the portray was trimmed on all 4 sides, and the trimmed items have been by no means discovered (though in 2021, AI was used to re-create the unique full portray). The goal of Operation Night Watch is to make use of all kinds of imaging and analytical methods to higher perceive the supplies Rembrandt used to create his masterpiece and the way these supplies have modified over time.
As previously reported, previous analyses of Rembrandt’s work recognized many pigments the Dutch grasp utilized in his work, together with lead white, a number of ochres, bone black, vermilion, madder lake, azurite, ultramarine, yellow lake, and lead-tin yellow, amongst others. The artist not often used pure blue or inexperienced pigments, with Belshazzar’s Feast being a notable exception. (The Rembrandt Database is the perfect useful resource for a complete chronicling of the various completely different investigative studies.)
Earlier this yr, the researchers at Operation Night Watch discovered uncommon traces of a compound known as lead formate within the portray. They scanned about half a sq. meter of the portray’s floor with X-ray powder diffraction mapping (amongst different strategies) and analyzed tiny fragments from the portray with synchrotron micro X-ray probes. This revealed the presence of the lead formates—shocking in itself, however the workforce additionally recognized these formates in areas the place there was no lead pigment, white, or yellow. It’s potential that lead formates disappear pretty shortly, which might clarify why they haven’t been detected in work by the Dutch Masters till now. But if that’s the case, why did not the lead formate disappear in The Night Watch? And the place did it come from within the first place?
Hoping to reply these questions, the workforce whipped up a mannequin of “cooked oils” from a seventeenth century recipe, which known as for mixing and heating linseed oil and lead oxide, then including sizzling water to the reacting combination. They analyzed these mannequin oils with synchrotron radiation. The outcomes supported their speculation that the oil used for mild elements of the portray was handled with an alkaline lead drier. The indisputable fact that The Night Watch was revarnished with an oil-based varnish within the 18th century complicates issues, as this will likely have offered a contemporary supply of formic acid, such that completely different areas of the portray wealthy in lead formates could have shaped at completely different instances within the portray’s historical past.
This newest paper sheds extra mild on the portray by specializing in the preparatory layers utilized to the canvas. It’s identified that Rembrandt used a quartz-clay floor for The Night Watch—the primary time he had executed so, maybe as a result of the colossal measurement of the portray “motivated him to search for a less expensive, much less heavy and extra versatile different for the bottom layer” than the pink earth, lead white, and cerussite he was identified to make use of on earlier work, the authors recommended.
Fréderique Broers
Per the authors, that is the primary time that 3D X-ray imaging methods have been used: X-ray fluorescence and X-ray ptychographic nano-tomography utilized to an embedded paint fragment comprised of solely the quartz-clay floor. The authors keep that microscale evaluation of historic work normally depends on 2D imaging methods (e.g., mild microscopy, scanning electron microscopy, synchrotron radiation spectroscopy), which solely yield partial details about the dimensions, form, and distribution of pigment particles under the seen floor.
The 3D strategies seize extra element by comparability, revealing the presence of an unknown (and sudden) lead-containing layer situated simply beneath the bottom layer. The authors recommend that this could possibly be attributable to utilizing a lead compound added to the oil used to arrange the canvas as a drying additive—maybe to guard the portray from the damaging results of humidity. (Usually a glue sizing was used earlier than making use of the bottom layer.)
The Night Watch initially hung within the “nice corridor” of a musketeer capturing vary in Amsterdam and confronted home windows. The authors notice that for the reason that Middle Ages, pink lead in oil has been used to protect stone, wooden, and metallic in opposition to humidity, and one modern supply mentions utilizing lead-rich oil as an alternative of the everyday glue to maintain the canvas from separating after years of publicity in humid environments. And that newly found lead layer could possibly be the rationale for the weird lead protrusions in areas of The Night Watch with no different lead-containing compounds within the paint. It’s potential that lead migrated into the portray’s floor layer from that lead-oil preparatory layer under.
DOI: Science Advances, 2023. 10.1126/sciadv.adj9394 (About DOIs).