Category → pigments
Think You Can Identify A Van Eyck?
Three Maries At The Tomb by a Van Eyck brother, or possibly both.
Many art historians have eyed Three Maries At The Tomb and agreed that it’s a Van Eyck. What’s debated is whether Jan painted the artwork or whether it was his older brother Hubert. Or more likely, whether the painting was a sibling collaboration.
For example, the brothers both worked on the famous Ghent Altarpiece: An inscription on the back says it was started by Hubert and finished by Jan, six years after Hubert’s death.
However, art historians debate which brother had a greater influence on the paintings in the Ghent Altarpiece. Did Jan humbly follow his older brother’s stylistic lead or did Jan turn the artwork into a masterpiece with his own artistic flair? Continue reading →
Finish Fetish Chemistry
Gray Column, 1975–76, De Wain Valentine. Polyester resin. © De Wain Valentine
Consider this cultural cocktail: the 1960s and 70s surfing scene in Los Angeles, that era’s emerging aeronautical and chemical industries, plus a splash of flavor from Hollywood and the Beatniks.
The result is a group of artists called the Finish Fetish who produced minimalist sculptures often made from materials newly available in those decades, such as polyester.
Finish Fetish is “extra spit and polish in pop and minimal art plus space age materials.” This description (from Peter Plagens via artdesigncafe) explains the obsession with “finish”…which should not be confused with the Northern European Finnish.
One of the Finish Fetish is an artist called De Wain Valentine. Commercial resin available at the time “wouldn’t allow him to do what he wanted to do–which was to pour really big objects,” says Tom Learner, head of Modern and Contemporary Art Research at the Getty Conservation Institute.
Valentine wanted to create his extremely large sculptures in a single pour of polyester resin because creating the artwork in two steps interfered with the seamless look he was after. Continue reading →
Christians Artists Embellished Spain’s Muslim Paintings
The interior paintings of Granada's Madrasah Yusufiyya in Spain date from 1349. Credit: Carolina Cardell.
For nearly 800 years, the Islamic Moors occupied Spain, building extraordinary buildings that still draw hordes of tourists today. Case in point: the Alhambra.
Less well known is the Madrasah Yusufiyya of Granada, the only Islamic university from the Moorish era left standing in Spain. It was built in 1349 and operated for about 150 years, until the Christians conquered the region in the late 1400s.
The lovely Madrasah Yusufiyya was then used extensively by the Christians, most likely as administration buildings, says Carolina Cardell a conservation scientist at the University of Granada.
In fact the Christians liked the building so much, Cardell says, that in the last 500 years they have done a lot of touching up, repainting, restoring and embellishing of paintings covering the stucco and wooden interior walls of the Madrasah Yusufiyya.
Yet art historians haven’t really known the extent of these interventions. So over the past few years, while the Madrasah Yusufiyya has been under restoration, Cardell and her team of scientists took a closer look at the paintings with a suite of analytical technology. She’s just published a paper in Analytical Chemistry about the interventions to the Madrasah Yusufiyya over the past 500 years. Continue reading →
When Acrylic Paints Get A Spa Day
Andy Warhol's acrylic portrait of Brooke Hayward needed the surfactant that had exited the painting to be cleaned off. Conservation scientists used surface imaging technology to monitor the cleaning process. Credit: MOLAB.
When acrylic paint was introduced in the late 1940s it was a boon for artists with a penchant for instant gratification: Acrylics dry within hours, compared to the weeks and sometimes months it takes for oil paint to completely harden.
But few things in life are perfect, and acrylic paint is no exception. In order to keep pigments stable in the acrylic polymer base, paint makers had to include additives called surfactants. Unfortunately, after a few years or decades, the surfactants get itchy feet and rise out of the paint to the surface of the artwork.
Once there, these surfactants can leave a white film on priceless paintings and they can also be sticky, attracting dirt and grime to the artwork.
In this week’s C&EN, my colleague Celia Arnaud digs deep in to acrylic paint chemistry and talks with conservation scientists about what they do to remedy the problem of wandering surfactant.
Unfortunately, many existing solvents that might be used to clean off the surface of acrylic artworks tend to make the paint swell… This makes museum staff nervous because it’s not clear what long term consequence come from this swelling. Another problem is that solvents that don’t cause acrylic paints to swell aren’t typically good cleaners.
That’s why researchers at the Tate Galleries in London, the Getty Conservation Institute in LA and the DOW chemical company have teamed up to try and find a solvent that cleans but does not swell acrylic paint. At the same time researchers at the University of Delaware are working with Golden Artist Colors, a paint company, to work out good cleaning conditions for acrylic paintings.
If these researchers hit paydirt, acrylic paintings around the world will finally get that facial treatment they’ve all been needing.
Oldest Paint-Making Workshop Dates Back 100,000 Years
An ancient abalone shell used for paint making and storage. Credit: Science/AAAS.
When early humans wanted to paint their bodies, cave walls and anything else for that matter, they used ochre, the red and yellow pigments found in earth and rock.
Today archeologists are reporting the discovery of a 100,000 year-old ochre-making workshop—the oldest to date–in the Blombos cave along the Cape coast of South Africa.
This pushes back the date–by nearly a factor of two—for when early humans produced and stored chemical products such as paint. The next oldest evidence of a workshop dates from 60,000 years ago.
The discovery shows that 100,000-year-old humans “had an elementary knowledge of chemistry and the ability for long-term planning,” note the authors of the Science paper (DOI: 10.1126/science.1211535), which includes Norway’s Christopher Hensilwood.
It’s pretty of amazing to think that a group of Middle Stone Age humans had a paint factory in operation.
Apparently the ancient workers first ground the ochre pigments (which are iron oxides and hydroxides) out of rock. Then they heated up animal bones to extract fat and marrow which was used as a binder for the ochre pigments. The early humans also added a bit of charcoal to the mix.
Then the paint was stored in abalone shells. Normally there’s a little air hole found in such shells but the ancient workers blocked the hole so that the paint would last longer. Pretty smart for a caveman (or cavewoman).
Location, location, location. The Blombos cave along South Africa's Cape coast. Credit: Science/AAAS.
Incidentally, up on the embargoed Science media site, where journalists can download photos of the pigment-making artifacts, there’s also sequence of amazing shots of the coastal workshop cave.
I think it’s pretty clear that this workshop discovery also reveals that ancient humans were early adopters of the real estate truism: location, location, location.
Keeping Visitors Out To Keep Cave Paintings Safe
Guest post from Carmen Drahl, a C&EN’s Associate Editor and Haystack blogger.
Overview of the best preserved area of the famous Polychrome Chamber in Altamira Cave. At the end are members of the research team and micro-environmental monitoring station. © MNCN-CSIS, Spain
Growing up, I spent every summer in northern Spain, living in my grandmother’s Oviedo flat and wandering the city and surrounding villages with distant cousins. One of my greatest regrets is never having taken the 3 hour drive to what my grandma called “las Cuevas de Altamira”, the storied caves and UNESCO World Heritage Site that house some of the world’s most striking examples of Paleolithic art.
The caves have been closed to visitors on and off since their discovery in the late 1870s. But they’ve been shuttered indefinitely since 2002, because microbial colonies encroached on the priceless scenes of bison and deer on the stone ceilings. Government officials in Cantabria, the Spanish autonomous community where the cave is situated, would like to reopen Altamira to tourists. Today, in a policy forum in the journal Science (DOI:10.1126/science.1206788), researchers led by Cesareo Saiz-Jimenez from the Spanish Council for Scientific Research (CSIC), argue that would be a bad idea. The team, which has been dealing with the microscopic invaders firsthand, says that letting visitors back into the cave’s fragile ecosystem would quickly undo any good that the closure has done and could cause irreparable damage. Continue reading →
Conserving Mosaics: A Nod To The Chemistry Nobel Prize
When blogger David Bradley posted this lovely image of a Moorish mosaic, I knew I had to learn more about how tile art is conserved.
In honor of today’s Nobel Prize in chemistry to Dan Shechtman for the discovery of quasicrystals, I thought I’d write a little post on the world of mosaic art conservation.
Bear with me–there is a connection.
(This is precisely what I said when Paula Artal-Isbrand, a mosaics conservator at the Worcester Art Museum, answered the phone. Luckily, she didn’t deem me a random freak and then hang up.)
OK. So back to the Nobel Prize. Quasicrystals are regular patterns of atoms that never repeat themselves, much “like the fascinating mosaics of the Arabic world,” noted the prize’s press release.
This got me thinking–and blogger David Bradley too—because moments later he tweeted the perfect Moorish mosaic example you see here. And I knew I had to learn a bit more about mosaic art conservation and restoration.
Continue reading →
A Visit To The Opificio, Italy’s Primary Restoration Lab
An Opificio restorer working on a Vasari panel painting. © Sarah Everts.
Italy has no shortage of art, and when that art needs a face-lift, it takes a trip to the Opificio delle Pietre Dure e Laboratori di Restauro, the country’s national restoration laboratory.
Located in an elegant old stable in Florence, the Opificio is like a spa for cultural heritage artifacts, where paintings, frescoes and sculptures go for age-extending treatments.
When I visited, Cecilia Frosinini, an art historian and the Opificio’s director of mural paintings, was kind enough to give me a tour.
As we wandered through the extensive labs, dozens of restorers were working on a wide variety of pieces including Renaissance paintings sent from Budapest for anti-aging therapy, ceramic sculptures, water-damaged frescoes and a wooden statue of Christ that had been painted to look like bronze during an era when bronze was popular but too expensive for some budgets.
Looks like bronze but it's actually wood. © Sarah Everts
The Opificio has also been recently involved in everything from using ultraviolet light to bring out cool, hidden details in Giotto paintings to the restoration of Santa Croce Basilica’s famous frescoes.
Like many great things in Florence, the Opificio has its root with the city’s famous Medici family. The first half the Opificio’s Italian name translates to “workshop of semi precious stones.” And as the name suggests, the Medicis founded the Opificio in 1580s to produce furniture decorated with semi precious stones, Frosinini told me.
Time passed and the workshop began restoring their own pieces. By the 19th century, art made from other materials such ceramic, marble and jewelry, was also being restored, she added.
Continue reading →
Vincent Van Gogh’s Last Months
Vase with Fifteen Sunflowers. Credit: Wikimedia commons.
In the last year of Vincent van Gogh’s life, as his mental illness escalated and before his suicide in 1890, the Dutch impressionist painter voluntarily committed himself in to two French hospitals.
The isolation didn’t thwart van Gogh’s productivity–he painted some 200 paintings during the 15 months he spent in treatment. Nor did the isolation prevent him from experimenting with trendy new pigments bequeathed by the industrial revolution, such as chrome yellow, which he used to paint his famous sunflower series. This pigment fell out of favor by the 1950s when its lead and chromate make-up was found to be toxic.
Unfortunately, chrome yellow and other then-trendy pigments degrade if they are exposed to light. For example, the degradation turns the bright yellow pigment into a rather sad looking green color. Earlier this year Koen Janssens, at the University of Antwerp, in Belgium, explained the chemistry behind this degradation, by using X-ray spectroscopy to show that when the chromium in the yellow paint was subjected to too much light, it went from a hexavalent state to a trivalent state. Many media outlets reported on the discovery, including C&EN and Newscientist.
The MOLAB van on the road in Greece. Credit: MOLAB.
Now Janssens has turned his attention to the so-called red lake pigments that van Gogh used in paintings during the 15 months of his life. Janssens recruited the help of MOLAB, a group of roaming scientists who travel around Europe with high tech, portable equipment. Their gear can help him study light degradation of the valuable art without harming it.
Last week, the MOLAB team, aka CHARISMA, drove 1500km from Perugia, Italy, to the Kröller-Müller Museum, in Otterlo, in the Netherlands. The Kröller-Müller has 22 paintings from van Gogh’s last months of life, and with the help of the mobile lab, the researchers can study the red pigment degradation without moving or harming the artwork.
Hopefully the new research will clarify the chemistry of the paint breakdown so that further degradation of van Gogh’s work can be avoided.
I can’t help thinking about the tragic irony of it all… that as van Gogh’s mental health was rapidly deteriorating, he was expressing himself using paint that was itself unstable.
Artful Space Tools
Thank you, Mars, for indirectly giving art researchers a helping hand. Credit: Wikipedia Commons.
When cultural heritage scientists go on the road, one of the most useful tools they take with them is something developed for Mars exploration: a hand-held X-ray fluorescence spectrometer. The Art Institute of Chicago’s Francesca Casadio wrote a snappy little ode to the machine, which NPR awesomely calls a “science gun.”
When researchers point the admittedly weapon-like device at a painting or a sculpture, they are able to find out which elements are present in the artwork. So for example, Casadio has used the machine to discover that about 1000 years ago, Chinese artists used a red, mercury-based paint called vermillion to decorate the lips of a female sculpture.
She also discovered that sometime in the 1800s an over-enthusiastic restorer used a zinc-based paint to give the sculpture “a new coat of lipstick,” Casadio told NPR. Hear the whole NPR piece here.
Casadio launching X-rays with her science gun at the Impressionists. Credit: Art Institute of Chicago.
I heart the space connection. Astrochemists needed rugged and portable equipment to analyze the elemental make-up of the Martian landscape. The X-ray device also doesn’t harm whatever it is analyzing because researchers don’t need to remove a piece of the sample to do the analysis.
Instead, X-rays are directed on to the artwork or Martian rock and they either get scattered or absorbed in a way that reveals which elements are in the sample.
All these characteristics fit the bill for cultural heritage science. These researchers need sturdy, portable, non-invasive devices to study priceless art in caves, at archeological sites or even at a private collector’s home. And that’s why Casadio calls X-ray fluorescence spectrometers “the most exciting high-tech tools you’ve never heard of.”
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