Researchers dated the white lead-based paints used in several paintings – including The Cattle Ferry, illustrated, a 1655 painting by Nicolaes Pietersz Berchem – to more accurately determine the dates and places of their creation. Image courtesy of Rijksmuseum Netherlands
December 1 (UPI) – A new isotopic analysis of 77 paintings created by 27 Dutch artists has revealed subtle differences in a common white pigment that are directly related to supply routes altered by historical conflicts, researchers said on Wednesday.
With the new technique, researchers identified a change in the supply of lead-based paint coinciding with the English Civil War in the mid-1640s and the end of the Eighty Years’ War around the same time. in what is now the Netherlands, Belgium and Luxembourg. .
The white paint used in the 77 paints exhibited a greater variation in isotopic values, which are used to measure lead levels, between 1648 and 1680, according to the data.
These changes could be linked to rising tensions and wars during this period, which impacted the provenance of lead for paint and other uses, the researchers wrote in an article published by the newspaper Wednesday. . Scientists progress.
“We identify a significant change in the isotopic composition of lead from white lead between 1642 and 1647 [and] this change has coincided with some important socio-economic events which most likely have altered the lead supply chain, ”co-author Paolo D’Imporzano told UPI in an email.
“The differences in lead isotopic ratios found in paintings made over different decades, especially before and after the transition, may (…) help art researchers answer some questions about controversial paintings,” he said. said D’Imporzano, associate researcher at the University of Vrije in Amsterdam.
The English Civil War, a series of conflicts fought between 1642 and 1651, was a battle between those who supported the establishment of a republic and those who favored the monarchy as head of state.
The Eighty Years’ War, or Dutch War of Independence, was a revolt in parts of present-day Netherlands, Belgium and Luxembourg against Philip II of Spain.
The two conflicts led to growing tensions across Europe and disrupted the flow of goods across the continent, according to historians.
Lead has been used in the production of paint for centuries, and isotopic analysis of lead, which measures lead levels in paints, has been used to date works of art since the 1960s.
The technique was used to examine differences in pigment production, establishing, for example, clear differences between lead white paint produced in northern and southern Europe.
For the analysis, D’Imporzano and his colleagues used paintings with known production dates to calibrate an international database used to help attribute and authenticate other works of art across Europe.
They tested the levels of lead in white paint samples from Dutch paintings created between 1588 and 1700, four of which dated from periods when the artists were known to have traveled outside the Netherlands.
Based on the variations in the isotopic ratios of lead for paints, there were two groups centered on the periods 1588 to 1642 and 1648 to 1680.
The first group points to a lead supply chain used to produce lead-white paint that has remained constant for at least four decades, the researchers say.
A transition to higher lead isotope ratio index values, however, occurred between 1642 and 1647, indicating a change in the source of lead supply coinciding with the two conflicts, they said.
Wars, and the corresponding demand for weapons, led to a steady increase in the demand for lead during this period.
“England was the main producer of lead and saw an expansion in production leading to the depletion of parts of some mines and the opening of new ones,” D’Imporzano said.
“These developments have likely caused changes in the average lead isotopic ratios of the product added to the market,” he said.
Likewise, the conclusion of the Eighty Years’ War, which led to the independence of the Dutch Republic, resulted in new trade agreements and, as a result, potential changes in lead supplies, according to D’Imporzano. .
In a case study published in the Science Advances article, Dutch artist Willem Drost’s painting Cimon and Pero, believed to have been created in Venice in 1657, was found to have lead white with consistent isotopic values. to those found in the Netherlands. around 1650.
“Performing an isotopic analysis of lead on white lead can now help to better locate 17th century Dutch paintings over time and this information can then be used to help understand when a painting is made,” D’Imporzano said. at UPI.
“By combining this information with other data, such as an artist’s travels, it is possible to make more precise attributions” on paintings for which the artist is currently unknown, he said.