Tag: painting

Arsenic and Artistry: Uncovering Secrets in Pietro Lorenzetti’s Paintings

Arsenic and Artistry: Uncovering Secrets in Pietro Lorenzetti’s Paintings

Synchrotron studies highlight the toxic legacy of ground-breaking 14th century art techniques

In 2013, the Ferens Art Gallery in Hull acquired Pietro Lorenzetti’s Sienese gold-ground panel Christ between Saints Paul and Peter, a newly discovered example of the Italian artist’s work. For four years, the painting underwent intensive conservation treatment and scientific study at The National Gallery in London, revealing vibrant colours and minute details previously obscured by layers of discoloured varnish and earlier conservation efforts. Another of Lorenzetti’s works, Virgin and Child Enthroned and Donor, Angels, hangs in the Philadelphia Museum of Art. In work recently published in Studies in Conservation, researchers from the National Gallery and the Natural History Museum in London worked with scientists from Diamond’s I18 beamline to analyse samples of mordant gilding taken from both paintings, where previous studies had shown the presence of a mordant tinted with orpiment (a bright yellow mineral pigment containing arsenic) used to adhere overlying layers of silver and gold leaf. Synchrotron microfocus X-ray techniques (SR µ-XANES, µ-XRF and µ-XRD) were used to reveal the chemical migration and nature of altered phases in the orpiment-containing mordant layer. The results add to our understanding of the painting techniques used during this exciting period, and will inform ongoing conservation and restoration efforts.

Investigating Lorenzetti’s Masterpieces

Italian painter Pietro Lorenzetti was active from the early to the mid-fourteenth century. He and his younger brother Ambrogio foreshadowed the art of the Renaissance, experimenting with three-dimensional and spatial arrangements. Previous research carried out by The National Gallery and Philadelphia Museum of Art suggests that two of Lorenzetti’s artworks – Virgin and Child Enthroned and Donor, Angels and Christ between Saints Paul and Peter – may have been part of a multi-panelled altarpiece (polyptych), possibly created for the church of Santa Maria dei Servi in Siena. Comparison of X-radiographs of the two panels identified corresponding structural features suggesting that the panels were cut from consecutive flitches of the same log.

says Dr Helen Howard of the National Gallery, London, says:

At this particular time, artists were using a lot of new methods and experimenting in new ways to try to obtain particular effects, particularly with the use of metal leaf. A contemporary painting by Giotto in the Scrovegni chapel, for example, uses four different types of metal leaf: gold, silver, part-gold (where gold and silver leaves are beaten together to form a single leaf) and gold over tin. Artists could also use varnishes and coloured glazes over the various metal leafs. In addition, the colour of the underlying bole or mordant could affect the overall appearance and mordant gilding might also have a slightly raised effect. The end result is very complex, and understanding what materials the artist used – and how they have degraded – is important for restoring and conserving the artwork.

During the conservation of Christ between Saints Paul and Peter, the research team took tiny samples of mordant, one from the golden highlights on Christ’s drapery and another from the golden threads depicted in the borders of Saint Peter’s robes. Studies showed that Lorenzetti had used a complex orpiment-tinted mordant to adhere two separate layers of silver and gold leaf, and that these materials had degraded over time.

The unusual composition of the samples prompted the team to request that the Philadelphia Museum of Art take comparative samples from gilded areas of Virgin and Child Enthroned and Donor, Angels, where a similar stratigraphy and deterioration was detected.

Microscopic Insights into Paint Samples

The researchers worked with scientists on Diamond’s I18 microfocus beamline, using synchrotron X-ray techniques to gain a deeper understanding of the layered paint samples.

Dr Howard explains:

The beamline at Diamond was crucial because we could focus down to about 2 microns and look across all the layers to see where the deterioration products are. We used µ-XRF (micro X-ray fluorescence) to map the products of deterioration, and µ-XRD (micro X-ray diffraction) and µ-XANES (micro X-ray Absorption Near Edge Structure). The µ-XANES was particularly important, because it shows us the amorphous products, as well as the crystalline. It’s one of the only ways we have to do that, so it’s very, very important.

Read more on Diamond Light Source website

Image: Pietro Lorenzetti, Christ between Saints Paul and Peter, about 1320. Detail showing the mordant gilding on St Peter’s robes. © Ferens Art Gallery, Hull Museums.

Credit: The National Gallery, London.

Unusual compound found in Rembrandt’s The Night Watch

Unusual compound found in Rembrandt’s The Night Watch

An international team of scientists from the Rijksmuseum, the CNRS, the ESRF the European Synchrotron, the University of Amsterdam and the University of Antwerp, have discovered a rare lead compound (named lead formate) in Rembrandt’s masterpiece The Night Watch. This discovery, which is a first in the history of the scientific study of paintings, provides new insight into 17th-century painting technique and the conservation history of the masterpiece. The study is published in Angewandte Chemie – International edition.

The Night Watch, painted in 1642 and displayed today in the Rijksmuseum Amsterdam (The Netherlands), is one of Rembrandt’s most important masterpieces and largest work of art. In the framework of the 2019 Operation Night Watch, the largest research and conservation project ever undertaken for Rembrandt’s masterpiece, an international research team joined forces to study how the painting materials react chemically and with time.

The team of scientists combined multi-scale imaging methods in order to chemically study the materials used by Rembrandt in The Night Watch. A X-ray scanning instrument developed at the University of Antwerp (Belgium) was applied directly to the painting, while tiny fragments taken from the painting were studied with synchrotron micro X-ray probes, at the ESRF, the European Synchrotron (France), and PETRA-III facility (Germany). These two types of analyses revealed the presence of an unexpected organo-metallic compound: lead formates. This compound had never been detected before in historic paintings: “In paintings, lead formates have only been reported once in 2020, but in model paintings (mock-up, fresh paints). And there lies the surprise: not only do we discover lead formates, but we identify them in areas where there is no lead pigment, white, yellow. We think that probably they disappear fast, this is why they were not detected in old master paintings until now”, explains Victor Gonzalez, CNRS researcher at the Supramolecular and Macromolecular Photophysics and Photochemistry (PPSM) laboratory (CNRS/ENS Paris-Saclay) and first author of the paper.

Read more on the ESRF website

Image: The Night Watch, Rembrandt van Rijn, 1642

Credit: Rijskmuseum Amsterdam

Out of the blue: X-rays shed light on on ultramarine blue in masterpieces

Out of the blue: X-rays shed light on on ultramarine blue in masterpieces

According to a survey led by Nature in 2016, 70% of scientists admitted they could not reproduce another scientist’s experiments and more than half could not reproduce their own. In order to improve sharing and, in turn, enhancing innovation, the European Union is working on implementing the European Open Science Cloud (EOSC), a kind of “library” of all experimental raw data and methods, available to everyone.

The ESRF is doing its bit by leading the PaNOSC (Photon and Neutron Open Science Cloud) project: “We are in the process of implementing the ESRF Data Policy to organise the data from experiments in an archive, which ultimately everyone will be able to access. The scientific teams will have three years to keep their data closed to the public, and after that any other scientist can try to repeat or do new data analysis of the very same experiment if he or she wishes to”, explains Andy Götz, coordinator of the project. The final goal of PaNOSC and the EOSC is to make data from publicly funded research in Europe Findable, Accessible, Interoperable and Reusable (FAIR).

>Read more on the ESRF website

Image: Alessa Gambardella at a stereomicroscope looking at ultramarine blue in Hendrick per Brugghen’s The Adoration of the Kings (1619)

Credit: Courtesy of Department of Conservation & Science, Rijksmuseum.

Saving Rembrandt for future generations

Saving Rembrandt for future generations

New research on beamline I18 at Diamond Light Source investigates preservation techniques for Old Master paintings.

The surface of many Old Master paintings has been affected by the appearance of whitish lead-rich deposits, which are often difficult to fully characterise, thereby hindering conservation. Painted in 1663, Rembrandt’s Homer is an incredibly valuable and much-loved painting. Like many Old Masters it has a long and eventful past, which has taken its toll on the painting’s chemistry. The test of time and environmental factors, combined with the painting’s history, caused a barely visible, whitish crust to form on the surface of the painting. This crust indicates that chemical reactions are occurring which could potentially pose as risk for Homer and other old paintings if not kept in stable museum conditions.
A paper in ChemComm (Royal Society of Chemistry) has been published by a team of conservation scientists from the Mauritshuis in the Hague and the Rijksmuseum in Amsterdam, University of Amsterdam and scientists from Finden Ltd, UCL and Diamond Light Source, the UK’s National Synchrotron. Called “Unravelling the spatial dependency of the complex solid-state chemistry of Pb in a paint micro-sample from Rembrandt’s Homer using XRD-CT,” this paper is particularly timely given the celebrations occurring in 2019 to mark 350 years since the death of Rembrandt and the Dutch Golden Age. A paint micro-sample from Rembrandt’s Homer was imaged using X-ray Diffraction Computed Tomography (XRD-CT) in order to understand the evolving solid-state Pb chemistry from the painting surface and beneath.

>Read more on the Diamond Light Source website

Image: Stephen Price, Lead author from Diamond Light Source and Finden Ltd.

The secret to Rembrandt’s impasto unveiled

The secret to Rembrandt’s impasto unveiled

Rembrandt van Rijn revolutionized painting with a 3D effect using his impasto technique, where thick paint makes a masterpiece protrude from the surface. Thanks to the ESRF, three centuries later an international team of scientists led by the Materials Science and Engineering Department of TU Delft and the Rijksmuseum have found how he did it.

Impasto is thick paint laid on the canvas in an amount that makes it stand from the surface. The relief of impasto increases the perceptibility of the paint by increasing its light-reflecting textural properties. Scientists know that Rembrandt, epitome of the Dutch Golden Age, achieved the impasto effect by using materials traditionally available on the 17thcentury Dutch colour market, namely lead white pigment (a mixture of hydrocerussite Pb3(CO3)2.(OH)2 and cerussite PbCO3), and organic mediums (mainly linseed oil). The precise recipe was, however, unknown until today.

>Read more on the European Synchrotron (ESRF) website

Image: Scientist Marine Cotte on beamline ID21.
Credit: Steph Candé.

Enlightening yellow in art

Enlightening yellow in art

Scientists from the University of Perugia (Italy), CNR (Italy), University of Antwerp, the ESRF and DESY, have discovered how masterpieces degrade over time in a new study with mock-up paints carried out at synchrotrons ESRF and DESY. Humidity, coupled with light, appear to be the culprits.

The Scream by Munch, Flowers in a blue vase by Van Gogh or Joy of Life by Matisse, all have something in common: their cadmium yellow pigment. Throughout the years, this colour has faded into a whitish tone and, in some instances, crusts of the paint have arisen, as well as changes in the morphological properties of the paint, such as flaking or crumbling. Conservators and researchers have come to the rescue though, and they are currently using synchrotron techniques to study in depth these sulphide pigments and to find a solution to preserve them in the long run.

“This research has allowed us to make some progress. However, it is very difficult for us to pinpoint to what causes the yellow to go white as we don’t have all the information about how or where the paintings have been kept since they were done in the 19th century”, explains Letizia Monico, scientist from the University of Perugia and the CNR-ISTM. Indeed, limited knowledge of the environmental conditions (e.g., humidity, light, temperature…) in which paintings were stored or displayed over extended periods of time and the heterogeneous chemical composition of paint layers (often rendered more complex by later restoration interventions) hamper a thorough understanding of the overall degradation process.

>Read more on the ESRF website

Image: Some of the mock-up paints, prepared by Letizia Monico. Credits: C. Argoud.

The enigma of Rembrandt’s vivid white

The enigma of Rembrandt’s vivid white

Some of Rembrandt’s masterpieces are at the ESRF for some days, albeit only in minuscule form. The goal: to unveil the secrets of the artist’s white pigment.

Seven medical students surround a dead body while they attentively look at how the doctor is dissecting the deceased. The scene is set in a dark and gloomy environment, where even the faces of the characters show a grey tinge. Strangely, the only light in the scene is that coming from their white collars and the white sheet that partially covers the body. The vivid white creates a perplexing light-reflecting effect. Welcome to painting The anatomy lesson of Dr. Nicolaes Tulp, a piece of art displaying the baffling technique of the impasto, of which Rembrandt, its author, was a master.

Impasto is thick paint laid on the canvas in an amount that makes it stand from the surface. The relief of impasto increases the perceptibility of the paint by increasing its light-reflecting textural properties. Scientists know that Rembrandt achieved the impasto effect by using materials traditionally available on the 17th century Dutch colour market, namely the lead white pigment (mix of hydrocerussite Pb3(CO3)2.(OH)2 and cerussite PbCO3), chalk (calcite CaCO3) and organic mediums (mainly linseed oil). The precise recipe he used is, however, still unknown.

>Read more on the European Synchrotron website

Image: The anatomy lesson of Dr. Nicolaes Tulp, by Rembrandt.

 

Pigments in Oil Paintings Linked to Artwork Degradation

Pigments in Oil Paintings Linked to Artwork Degradation

Scientists have observed how lithium moves inside individual nanoparticles that make up batteries.

The finding could help companies develop batteries that charge faster and last longer. Experts have long known that as oil paintings age, soaps can form within the paint, degrading the appearance of the artworks. The process significantly complicates the preservation of oil paintings—and cultural manifestations, which the paintings themselves help to preserve.

“These soaps may form protrusions that grow within the paint and break up through the surface, creating a bumpy texture,” said Silvia Centeno, a member of the Department of Scientific Research at the New York Metropolitan Museum of Art (The Met). “In other cases, the soaps can increase the transparency of the paint, or form a disfiguring, white crust on the painting.”

Scientists do not understand why the soaps take on different manifestations, and for many years, the underlying mechanisms of how the soaps form remained a mystery.

“The Met, alongside our colleagues from other institutions, is trying to figure out why the process takes place, what triggers it, and if there’s a way we can prevent it,” Centeno said.

 

>Read more on the NSLS-II website

Picture: Scientists from Brookhaven Lab and The Met used beamline 5-ID at NSLS-II to analyze a microscopic sample of a 15th century oil painting. Pictured from left to right are Karen Chen-Wiegart (Stony Brook University/BNL), Silvia Centeno (The Met), Juergen Thieme (BNL), and Garth Williams (BNL).