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Archive → October, 2011

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.

Mercury In Platinum Prints Makes Things Sepia–Or Does It?

Experts have long thought the warm, brownish sepia look comes from mercury bichloride added in the development process, but research shows this is not necessarily true. Credit: Wikimedia Commons.

Around 1889, Gertrude Käsebier, a 37-year-old, unhappily married mother of three, decided to go to art school.

A decade later, around 1900, Käsebier’s photo studio in New York City was so successful that her platinum print portraits were “the thing to have,” in turn-of-the-century socialite circles, says Tram M. Vo, an independent conservator who has been collaborating with Dusan Stulik at the Getty Conservation Institute.

“At the time, photographers charged about $12 for 12 prints,” Vo says. “Käsebier charged people $25 just to sit for a photograph and $5 for a single print.”

There’s not a lot known about Käsebier’s techniques in the dark room because she didn’t leave many notes behind. So Vo is trying to learn about her methods using an analytical technique called X-ray fluorescence spectrometry (XRF). Conservation scientists use XRF to get a list of the chemical elements present in an artwork using X-rays—all without touching or destroying the artwork.

In particular, Vo wants to learn more about the so-called sepia look in many of Käsebier’s prints. Sepia is the word used to describe when black and white photographs have a brownish tint that gives the shots a warm feeling.

In today’s digital world, giving a photo a sepia look is just a Photoshop click away. But when Käsebier wanted to give her platinum prints the sepia look she had to use dark room chemistry.
Continue reading →

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 →