Art conservation that does more harm than good
Aug07

Art conservation that does more harm than good

Hindsight is 20-20, as they say. This week Art Daily* reported that a widespread preservation treatment, developed to help canvases survive humid environments, actually makes paintings more vulnerable when humidity levels soar.** “The wax-resin treatment was enormously popular in Europe and the U.S. during the 1950s and 1960s,” says Cecil Krarup Andersen at the Royal Danish Academy of Fine Arts, who made the discovery. “Many masterpieces, such as Rembrandts and Van Goghs were preventatively treated with wax-resin linings to help protect the artwork from humidity degradation. The treatment does exactly the opposite.” Anderson has just wrapped up her PhD work on the topic, a research project that began because museum staff at Statens Museum for Kunst were trying to figure out why Danish Golden Age paintings treated with wax-resin were not resisting the insults of time as well as they should. I needed a little background on wax-resin treatment which Andersen kindly provided: It was popularized in the 1800s by a Dutch restorer named Nicolaas Hopman. One of the first masterpieces to be treated was Rembrandt’s Night Watch in 1851. The overall motivation was logical: Hopman thought that coating the back of a canvas with beeswax and an extra layer of canvas would act as a protective support for the painting. Later on, he and others began mixing tree resin in with the wax because it added stiffness. Throughout the 20th century, the treatment gained popularity. Until the 1970s. That’s when conservators started talking about the importance of reversibility, the idea that any conservation treatment on artwork should ideally have an undo button, just in case a treatment turned out to have unforeseen, negative, long-term impacts or in case a better treatment came along sometime in the future. At a conference in Greenwich, England, in 1974, a group of high profile conservators decided that wax-resin treatments were not reversible and should be discontinued, Andersen says. Wax-resin treatments were gradually phased out, but it was too late for thousands of masterpieces that had already faced the hot iron. Initially conservators used irons to melt the wax-resin on to the back of paintings, upon which they adhered the extra canvas layer. Then in the 1950s, specialized heating tables were invented. These tables could uniformly heat the wax-resin and seal the back lining to the painting “in no time,” Andersen says. They made it easy for conservators to overdo it, she says. (As an aside, Andersen says the treatment additionally flattened out the texture in some paintings.) Another reason 1970s conservators became nonplussed with wax-resin was that the treatment actually changed the color of paintings. Sometimes the hot wax and resin would...

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Daisies, frankincense, mint, and mercury help preserve Richard the Lionheart’s heart
Mar07

Daisies, frankincense, mint, and mercury help preserve Richard the Lionheart’s heart

This is a guest blog post from Stu Borman, a C&EN senior correspondent for science, technology & education. A French-based research team recently had a rare opportunity to get to the heart—quite literally—of some 12th century European history. Using a battery of scientific equipment, they took a closer look at how the heart of English king Richard I was preserved for posterity. Also known as Richard the Lionheart because of his military prowess, Richard I was king of England from 1189 to 1199. He led a Crusade to the Holy Land in 1190, but the mission failed to take Jerusalem, its main objective. On the way back home he was imprisoned by an Austrian duke and the German emperor and then only released after payment of what was literally a king’s ransom. He died in 1199 when he was shot with a crossbow while besieging a castle in Chalûs, France. According to a then-common practice, his body was divided up for burial in multiple graves. His internal organs were buried in Chalûs, his heart was embalmed and placed in a tomb at Notre Dame de Rouen cathedral, and the rest of his body was buried at an abbey in southern France. In 1838, a lead box containing the remains of Richard’s heart was found at the cathedral. The box is engraved “HIC IACET COR RICARDI REGIS ANGLORUM”—“Here is the heart of Richard, King of England.” To learn more about how the seat of the king’s soul was preserved for posterity in medieval times, forensic medical investigator and pathologist Philippe Charlier of University Hospital Raymond Poincaré, in Garches, France, and coworkers analyzed Richard I’s mummified heart. The wide variety of techniques they used to get to the heart of the matter included everything from scanning electron microscopy to mass spectrometry. In their paper on the study, the team writes that the heart “was deposed in linen [and] associated with myrtle, daisy, mint, frankincense, creosote, mercury, and, possibly lime.” They conclude that the goal of using these materials was both to preserve the heart and keep it smelling good, insofar as possible. “This embalming method is of great importance, as we do not have any procedure or surgical treatise known for this period (end of the 12th century A.D.) describing the methodology and/or composition of the embalming material,” the researchers...

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Photo fraud: eBay to the rescue!
Feb25

Photo fraud: eBay to the rescue!

In the 1990s the market for photos exploded. As snapshots started selling for millions of dollars, sham photos also slipped into the fray before the art world had any way to authenticate originals. And so cultural heritage researchers had to play some serious catch-up, and quickly. That’s the gist of my recent cover story on photo conservation. It explores how two fraud cases helped turn the field from a niche research area to a mature science. And as always happens when reporting, many cool tidbits didn’t fit in to the final piece… In this case, the pivotal role eBay played to help researchers develop ways to catch fakes. But first, a bit of background on photo fraud: In the photo market, people will pay more money for an image when it was actually printed on paper by the photographer himself or herself. The price can also increase when the print is older. So, for example, the Getty Conservation Institute’s Art Kaplan told me that an Ansel Adams photograph printed in the 1920s can sell for hundreds of thousands of dollars, while the exact same photograph printed a few decades later (say, the 1970s) can sell for just tens of thousands of dollars. It turns out that researchers wanting to authenticate a photo spend a lot of time scrutinizing the paper on which it has been printed, because photo paper generally provides the best dating and provenance clues. For example, researchers look for chemicals called optical brighteners which were added to all photo paper to brighten images starting in the 1950s. If a photo is purported to have been made earlier than the 1950s, then it can’t have any optical brighteners in the photo paper. Likewise, in the 1880s, companies started adding a so-called baryta layer to the top of photo paper as a physical barrier between image and paper, so trace impurities in the paper wouldn’t leach into the image layer and wreck the picture. Each company used a different ratio of barium and strontium in the baryta layer, and companies also changed these ratios over time. Since most photographers were loyal to a particular photo paper brand, authenticators check to see whether a suspect photo has barium and strontium ratios that correspond to the photographer’s preferred company during the era when the photograph was supposedly printed. Of course to make these comparisons, you need an enormous database of reference photo paper, says Paul Messier, a photograph conservator who helped develop ways to authenticate Lewis Hine prints in one of the world’s first million-dollar photo fraud cases. “A switch flipped on when I was working on the Hine project,” Messier says. “I...

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Two million-year-old whale fossils printed with 3D technology
Feb17

Two million-year-old whale fossils printed with 3D technology

These may look like real fossils, but they are actually perfect plastic replicas of 2 million-year-old whale skeletons made using a 3D printer. This printing technology, which can create 3D versions of objects as diverse as a guns or the brain of a man with no memory, was hyped last week by President Obama when he said that 3D printing “has the potential to revolutionize the way we make almost everything.” The technology certainly saved the day for Smithsonian paleobiologist Nick Pyenson. Pyenson had been finishing up a research trip in Chile in 2011 when he decided to check out a local highway construction site in the Atacama Desert where workers had supposedly uncovered dozens and dozens of whale skeletons. “I didn’t really believe the rumors at first,” Pyenson says. But when he arrived, “It was unlike anything I’d ever seen.” Pyenson described the experience at the American Association for the Advancement of Science meeting in Boston. Local museum officials were racing to dig out the skeletons before highway workers paved over the area, Pyenson says. Although the skeletons clearly needed to be removed, a problem with removal is that spatial information about different constellations of fossilized bones is then lost. This information is essential for answering all sorts of interesting research questions, such as why so many whales died and were buried together two million years ago. For example, the whales could have swum into a bloom of toxic algae and died or they might have fallen victim to a landslide. Pyenson went home to DC and immediately recruited the Smithsonian’s in-house 3D imaging and printing team (aka the Laser Cowboys), who came back with him to Chile and spent a week imaging the whale fossils with a high resolution laser scanner. The team then went home and began analyzing the fossil images. They also also began printing out awesome replicas like the one you see above, which is many times smaller that the original. (The whale fossils span between 20-30 feet in real life.) Pyenson says the Smithsonian has industrial partners who will soon print out a full sized version pro bono, which would have otherwise cost the museum $1 million. It seems Pyenson’s team has already figured out why all these whales died but he’s staying mum about it, while the scientific paper winds its way through the peer-review process—so stay tuned. Once the discovery is published, Pyenson says they’ll put the data online so others around the globe can access and analyze it. Although this laser scanning and 3D printing could give researchers around the world the ability to study skeletons without physically handling them, old-school...

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When a Rembrandt copy is not a forgery
Jan25

When a Rembrandt copy is not a forgery

So you’d think that making a replica of a Rembrandt might be frowned upon by the art world, but this copy of “An old man in military costume” has full approval of its owners. In fact, the folks at the Paul Getty Museum in LA, asked their own intern to replicate the masterpiece as well as the hidden painting beneath it. It seems that there’s a pretty good reason for making the copy, or “mock-up” as the researchers call it. For years, museum researchers have known that there’s another painting beneath the military portrait. But they’ve had a tough time getting more than just a faint whiff of the image hidden below using standard analytical methods. Over the past few years, a new technique called scanning macro X-ray fluorescence (MA-XRF) has proven itself useful for uncovering hidden paintings on canvases by Van Gogh, Goya and others. The question is whether MA-XRF would work for Rembrandt’s military portrait. And specifically, whether a portable X-ray device was powerful enough to do the trick or whether the painting should travel to a more a powerful synchrotron X-ray source, such as in Hamburg (DESY) or at Brookhaven National Labs in New York. It comes down to the fact that museums don’t like shipping valuable and fragile art around the world unless it’s absolutely necessary. Enter intern Andrea Sartorius (who I momentarily hoped was a descendent of the 17th century Croatian weight-loss fanatic & innovator, Sanctorius Sanctorius. Sadly the names are not quite the same.) Anyway, Sartorius painted a copy of the original Rembrandt using the same kind of pigments and binder that he would have used, and she included another portrait below the military one. Then the copy was shipped around the world to be analyzed using X-rays from the various synchrotron sources and from the portable device. Turns out it’s worth the trip to more snazzy X-ray sources if you want to see the hidden painting below. The team argues in this paper that transporting the Rembrandt to a synchrotron facility is actually “useful and relevant.” The paper’s lead researcher, Matthias Alfred, praised the mock-up: “It is the first time that a painting was reproduced in such an elaborate way for these tests.” It seems that experiments on mock-ups help museum staff decide whether sending expensive art to outside labs for analysis is worth the risk and effort. And that, my friends, is how a fake Rembrandt can sometimes be a good...

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Authenticating Pieces Of The Berlin Wall
Aug13

Authenticating Pieces Of The Berlin Wall

Fifty one years ago today, communist officials in East Germany erected the Berlin Wall to stop the exodus of their citizens to capitalist West Berlin. The 155-km barricade came down 28 years later in 1989, and since then, every self-respecting tourist shop in town sells chunks of spray-painted concrete to anyone seeking a piece of 20th century history. Today’s price for a chunk of the Wall, as determined during my lunch-time walk to the local tourist shop from my office at the East-West border in Berlin: €4.95 or about $6.10. You can get a better deal if you buy these cellophane-wrapped mementos from street vendors. A few years ago, the rather ample supply of German history for sale got Ralf Milke, a geochemist at Berlin’s Free University, wondering whether he could find a way to authenticate pieces of the Wall. Since then he’s developed a technique that uses X-ray diffraction to confirm whether a supposed chunk of the Berlin Wall is indeed genuine. Milke did a series of X-ray diffraction experiments with definitely authentic pieces of the wall to get fingerprint spectra of several elements found in the Berlin Wall concrete, such as silicon from the quartz or calcium from the calcite used to make concrete. He also found that all the fingerprint spectra of Berlin Wall samples have an unusual mark. It’s probably a trace mineral found in the quarry in Rüdersdorf, near Berlin, where the calcite used in the Wall was mined, Milke explains. Exactly what that trace mineral or metal is remains a mystery, but if the unusual mark doesn’t show up in the x-ray diffraction experiment, then the chunk of concrete isn’t a piece of the Berlin Wall, Milke asserts. “It’s an easy yes or no answer,” he says. Milke has tried to get a little Berlin Wall authentication business going, but so far only a handful of people have been willing to pay the €5 he charges to verify samples. That hasn’t stopped him from testing the wares of Berlin Wall vendors around town, he says. Some of the more fraudulent vendors don’t even use concrete when they create Berlin Wall fakes. Of course if these petty crooks want to evolve into criminal masterminds, they could find a way to use calcite from the Rüdersdorf quarry to mix their own concrete, and thus produce a fake that cannot be identified by Milke’s method. But pieces of the wall—fake or real—are still pretty inexpensive. So I’d wager that it may be a while yet before it’s financially worthwhile for that level of criminal conspiracy to seep into Berlin’s tourist keepsake...

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