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Greening Up Conservation Science

My pedestrian Photoshop attempt to give an Egyptian sculpture a greener feel. With apologies to Amenhotep III and thanks to Wikimedia Commons.

Cultural heritage is important so valuable art and artifacts should be protected at any cost, right?

Not so, says May Cassar, the director of the Center for Sustainable Heritage at University College London.

Most museum, galleries and archives take it as a given that air conditioning and pollution filtration are a must for keeping valuable collections in comfortable living conditions, she says.

“But air conditioning and particularly pollution filtration come at a very high cost–not only to institutional budgets but also from an environmental point of view” because fossil fuels are consumed to drive these systems, Cassar explains. “To me it is a double standard to damage the environment outside but protect the environment inside for collections.”

She’s trying to encourage people in cultural conservation careers to consider the environment outside–and not just around valuable collections.

So for example, Cassar advocates that museums in temperate climates–such as the UK–accept some minor risks to collections if there is a possible gain for the environment. For example, a museum might normally use air conditioning to keep humidity in between 50-60%. If the building’s internal humidity would normally only ever range from 40-65%, reaching the outer extremes only rarely, it could be fine for the museum to eschew humidity control without substantially increasing risk to the collection, she says.

Of course, it’s true that some museums don’t have the luxury of a temperate climate… Consider the soul-destroying humidity of Washington DC’s summer months (I barely survived two of them), or the corrosion potential from the high salt concentrations found in the air around ocean-side museums, or the problem New York City’s sooty air pollution raises for valuable collections.

But there may be other ways for museum, archive and gallery staff to go green.
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Conservation Scientists Get Into The Vibe

Raman was used to identify the arsenic-based pigment on this Egyptian mask. Credit: Peter Vandenabeele

This week some 120 conservation researchers are facing the tragic hardship that comes from spending a week in Parma, Italy, where there is a conference called “Raman in art and archeology.”

This is not a conference about art made from tasty Japanese noodles. (That’s Ramen, silly!)

But if you caught the gratuitous pun in my headline, then you probably already know that Raman spectroscopy is an analytical technology that helps scientists study the vibrations and rotations that occur within molecules. Conservation scientists get giddy about Raman for a bunch or reasons, Peter Vandenabeele, an organizer of the conference, told me:

First: Raman is not picky about art. Which is to say that the technique can be used to study the chemical make-up of jewelry, oil paintings, Egyptian burial masks, glass, Mayan wall paintings… you get the picture.

Second: Portable Raman spectroscopy equipment is non-invasive, so it doesn’t hurt artwork. Scientists head to a museum, and shine low frequency laser light at a painting or sculpture which has mysterious molecular components that they want to know more about—such as a pigment that gives artwork brilliant color, or a pigment that is fading with time.
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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.
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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.”

Up Some Scaffolding, En Route To Heaven

At the top of the scaffolding in Capella Maggiore. ©Sarah Everts

During most of my visits to Italy, I end up with neck cramps after craning my head backward for hours to look at faraway ceiling frescoes in churches across the country. But last week, I found myself peering directly into the eyes of fresco angels at the top of the Capella Maggiore in Florence’s famous Santa Croce Basilica.

These frescoes have been under restoration since 2005 and for the next few months small groups of people can climb the scaffolding to view the artwork up close. The frescoes were painted in the 1380s by Agnolo Gaddi, a disciple of Giotto, one of the architects of the Italian Renaissance.

I climbed up the scaffolding with Mariarosa Lanfranchi, a restorer from the Opificio delle Pietre Dure, Italy’s foremost restoration laboratory. She’s been leading the fresco restoration project.

One of the first questions she asked me is whether I suffer from vertigo, because we would be going up about 30 meters to reach the very top of the cathedral. Assured that I wouldn’t suffer a panic attack, she began her awesome tour by telling me that the last restoration of part of the church’s frescoes was in the 1930 or 40s.

Angels up close. ©Sarah Everts

Since then, air pollution has coated the art with a layer of brownish grime. Meanwhile, construction around the city has covered the artwork with little chunks of gypsum dust. The frescoes are porous, and with the city’s high humidity, the gypsum penetrated into the frescoes, giving the artwork a rather speckled look, Lanfranchi explained.

To remove the grime and gypsum, the restorers used the “Florentine method,” a combination treatment of ammonium carbonate, followed by a treatment of barium hydroxide, Lanfranchi said. The first step of adding the ammonium carbonate dissolves the unwelcome dust and gypsum (calcium sulfate dihydrate) so that both can be removed from the surface and inside the fresco’s pores.
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Two-Faced Microbes: Dirty Fungi And Cleaning Bacteria

King Tut's tomb with brown spot stains. © The J. Paul Getty Trust, 2001

Microbes can be an ugly pain-in-the-butt for artifacts.

Even if the bacteria and fungi growing on heritage buildings, frescoes, space suits and archival documents can be killed, they often leave behind some rather unpleasant stains that are really hard to clean off the sensitive surfaces of artifacts. That’s the situation in King Tut’s tomb, for example, where fungi have left behind dark brown spots on the beautifully painted walls.

Today the Harvard Gazette wrote about this issue: At the request of Egyptian heritage officials, researchers at the Getty Conservation Institute swabbed the walls of King Tut’s tomb, and sent samples of the brown muck to Ralph Mitchell, a Harvard microbiologist who specializes in cultural heritage science. Getty chemists figured out that the dark spots are actually melanin–the same pigment that builds up in your skin when you get a tan–while Mitchell’s team figured out that the fungi are dead and probably won’t be producing any more browny spots. Mitchell thinks that the fungi initially grew because the tomb was sealed before the paintings inside were dry, suggesting that the teenage king was buried in a hurry. The still-wet surface thus provided tempting real-estate for melanin-producing fungi.

Cyanobacteria growing on the Luca Signorelli frescoes in Italy's St. Brizio Chapel caused a rosy discoloration. Credit: Wikimedia Commons.

It turns out that melanin-producing fungi have also stained marble in Italian cathedrals after an ill-advised attempt to protect the marble using acrylic polymers. The acrylic on the marble attracted the staining microbes who found the plastic to be a tasty meal. But microbes will also grow on buildings, art and artifacts that haven’t received unwise “protection.” For example, orangey carotenoid pigments are often left behind by bacteria on stone buildings, Mitchell says, and frescoes have been stained rosy red due to the phycoerythrin pigments produced by cyanobacteria.

The question remains: How does one remove these unfortunate discolorations? Continue reading →

When Picasso Went Industrial

Scientists are studying Picasso paintings to figure out if he used industrial paint. © Sarah Everts

Last week curators, conservators, and museum scientists congregated in Marseille, France, to discuss a quirky fad among painters such as Pablo Picasso, Joan Miró and Wassily Kandinsky. During the first half of the 20th century, these artists began using newly invented industrial paint called Ripolin, intended for walls, instead of traditional oil paints.

One major motivation was time: Industrial wall paint dries in a matter of hours, while oil paint can take months. Like the rest of us, these artists had moments of procrastination. Being able to produce work just days before the opening of a new exhibit was certainly a perk, says Francesca Casadio, an organizer of the conference From Can To Canvas, and the director of conservation science at the Art Institute of Chicago.

Artists had other motivations for using Ripolin, such as shocking the stodgy traditional art world by using an industrial product, Casadio says. Some motivations were probably purely aesthetic: Industrial paint was glossier than matte oil paint. And in addition, artists could achieve unusual textures on artwork surfaces with the quick drying paint.
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Conserving Canada’s Valuables

The Pimple, Evening, by Group of Seven painter A.Y. Jackson. Credit: Wikimedia Commons.

Canada may not be rife with Roman ruins and Rembrandt masterpieces but the country has more than enough art and artifacts—such as one-of-a-kind First Nations leather work, Group of Seven landscape masterpieces and famous hockey gear–to keep cultural heritage scientists at the Canadian Conservation Institute in Ottawa very busy.

With an annual budget of $12 million (CAD) from the federal government, the CCI’s mission is to provide scientific support to some 2500 museums and 1000 archives across Canada.

I was passing through Ottawa last weekend and managed to slip in a visit to the CCI headquarters, where Charlie Costain, the CCI’s director of research, conservation and scientific services took me on a great tour of the warehouse laboratories. Continue reading →