A lot of science goes into saving masterpieces from decay and damage (Image: Tate)
Hirst’s shark decayed in its tank. Van Gogh’s sunflowers turned brown. A vandal scrawled on a Rothko. Here’s how masterpieces are fixed – if artists allow it
IT TOOK just seconds for self-styled art anarchist Wlodzimierz Umaniec to calmly step up to the giant Mark Rothko canvas hanging in London’s Tate Modern gallery and graffiti his signature and a slogan across one corner in permanent ink.
Advertisement
The damage caused to Rothko’s 1958 masterpiece was considerable. Glazed areas made with egg and dammar resin had been destroyed, while in unglazed parts the ink had seeped to the back of the canvas through complex layers of oils, pigments, colourants and glues.
Removing the graffiti from Rothko’s Black on Maroon took painstaking work (Image: Kate Rothko Prizel and Christopher Rothko/DACS 2014)
The 18-month scientific analysis and painstaking restoration that followed shone a rare spotlight on some of the complexities of art conservation. “We found out during that process how hard it is to paint like Rothko,” says Bronwyn Ormsby, senior conservation scientist for the UK’s Tate galleries.
The Rothko restoration was aided by a copious body of prior documentation on his materials and technique. But other artists are pushing conservation science into uncharted areas, with work fashioned from materials as diverse as soap and chocolate, blood and faeces (yes, some modern art really is crap). In the early 1960s, New York’s Museum of Modern Art (MOMA) turned down a over concerns about maintaining a work whose centrepiece was a stuffed angora goat. Vermin were one major worry.
Old masters are objects of flux and change too, and while we know much about conserving them, techniques are still far from perfect – pigments discolour, varnishes crack, canvases warp under centuries of stress.
This capacity for change and degradation in the materials of an artwork is what conservators call “inherent vice”. Applying science to the problem has helped restore many deteriorating works to their former glory. But with the challenge of new materials, some of the restoration techniques required are so extensive that it raises another question: is what we are left with the same as the original? And if not, should we be bothering to rescue them at all?
Conservators today are as likely to have backgrounds in chemistry or physics as art history. “The founding of museum laboratories was a turning point – at Harvard’s Fogg Museum in Massachusetts and the Louvre in the 1920s, then here in the 1930s,” says , head of science at London’s National Gallery.
These teams often collaborate with scientists at the cutting edge of seemingly unrelated fields. Famously in 2011, X-ray techniques proved crucial when at the University of Perugia in Italy set out to solve a long-standing mystery around some of the most renowned works of Vincent van Gogh.
Her international team, which included researchers from the Louvre in Paris, wanted to know why the yellow paint in a number of the great artist’s works, including some – but, intriguingly, not all – of his iconic Sunflower series had turned a dull brown.
They collected minute samples from brown sections and subjected them to the powerful X-ray generator at the in Grenoble, France. First, X-ray fluorescence (XRF) was used to determine which chemical elements were present in the offending pigment. When a fine X-ray beam is aimed at a substance, it causes changes in the energy levels of its atoms. This triggers the release of secondary X-rays whose energies depend on the structure of the atom hit by the original beam. Analysis of these X-rays shows which elements are present. A variant of XRF called XANES (X-ray absorption near edge spectroscopy) gives the precise chemical state of the atoms.
Van Gogh had painted with chrome yellow pigment, also known as lead chromate. The analysis revealed that around two-thirds of the chromium in the darkened samples had changed from bright yellow chromium(VI) to the darker green chromium(III), also known as viridian green. Together with some of the paint oxidising over time, this was enough to produce brown. But why did the change occur in just some of van Gogh’s yellows?
The reason, ironically, turned out to be the artist’s efforts to make some of his yellows even brighter. Van Gogh had mixed the basic lead chromate pigment with a white powder based on lead sulphate. The sulphate reacted with the chromium under the influence of light to change it from the (VI) to the (III) state.
Scientific investigations such as these are useful not only for finding out how an artwork has changed, but for understanding how to deal with damage, such as that done to the Rothko by Umaniec’s pen. Nine months were spent analysing the ink, using gas chromatography to work out its precise chemical make-up, then consulting with experts worldwide to whittle down thousands of possible combinations of solvents to a shortlist that might remove the ink without damaging Rothko’s materials.
Even after hitting on a blend of benzyl alcohol and ethyl lactate, several months had to be spent testing removal methods on artificially aged canvas plus a 1950s primed canvas supplied by the Rothko family. “One scientific challenge was that Rothko used so many different kinds of media to get a beautiful luminous effect,” says Ormsby. Then there was the highly penetrating nature of the graffiti ink. This could not be completely removed – some of the damage can still be seen in bright light. But the team’s hope was to be able to restore the painting so that it didn’t stand out in a room of around eight other Rothkos. “And we achieved that,” Ormsby says.
At least Ormsby was dealing with paint. In 1991, when British artist Damien Hirst put a shark in a tank in the name of art, he didn’t realise the pickle that would ensue. Hirst’s shark began to decompose, the preserving liquid clouding and the skin starting to wrinkle.
Despite its increasingly sorry state, the work was bought in 2004 for several million dollars. So Hirst had no choice but to address the issue. His first attempt to salvage the piece was to skin the shark, tan its hide, then drape it around a shark-shaped fibreglass frame.
Unfortunately, this made an object intended to evoke metaphysical dread look more like a cheap prop at a Jaws convention. Eventually, Hirst decided to remake the sculpture with proper conservation in mind, calling in , senior fish curator at London’s Natural History Museum.
Alcohol bath
“Preservation is an ongoing experiment,” says Crimmen, as he hauls on a tangle of clanking chains in the bowels of the museum to uncover a huge tank full of big fish and snakes, immersed in a bath of brown alcohol. “There’s a lot we don’t know about the chemistry. To a great extent it depends on what you want to do with a specimen.”
Although Crimmen firmly backs alcohol as the best long-term preservation medium, an artist concerned with aesthetics might opt for formalin. It is paler and more transparent than the dark brown of a strong alcohol-based solution. So it proved. “Damien said formalin is part of the artwork itself – he likes the colour,” says Crimmen, adding that the flammability of alcohol was another issue when it came to sticking a huge tank of the stuff in a public gallery, or on a plane if it needs transporting.
If Hirst’s choice of preserving liquid wasn’t the problem, what had gone wrong? “When I went to look at the specimen I saw definite tissue shrinkage manifesting in the skin, due to improper fixation inside the body,” says Crimmen. “If you fix tissue in formalin it’s got to get all the way in, and the only way to do that is to inject.” Sharks are especially difficult, he says. “You couldn’t really choose a more problematic animal. Their body cavity is largely taken up by this enormous liver, and if it starts to break down – which happens if the fluid is not properly injected – the whole thing starts to shrink.” Crimmen finds no fault with Hirst, though. “It was a very easy mistake to make. Little information would have been available to him.”
In fact, Hirst’s choices demonstrate the challenge posed by the interplay of inherent vice with artistic knowledge. “When I lecture at art schools, I am surprised how little information about art materials is taught,” says , a conservation specialist at New York University.
Take artist brothers Naum Gabo and Antoine Pevsner. In the 1920s and 30s, they made a series of abstract sculptures in cellulose nitrate and cellulose acetate, following a modernist credo of testing the artistic potential of new materials. They knew nothing of plastic’s vulnerability to disintegration, discolouration, crazing and warping. Today, their sculptures lie in tatters in museum back rooms as prime examples of what conservators have dubbed “dead art”. “It’s sad,” says Ormsby, “but all we can do is analyse it, and if it’s gone, it’s gone.”
Is it acceptable to make replicas of dead art? Ormsby says her team has grappled with that idea for the Gabo sculptures, but hasn’t done it yet. “We got as far as creating 3D digital models to have replicas made,” she says.
Such interventions highlight a tension between artists’ wishes, the object itself, and the wishes of owners, whether gallery or collector. Given how much some art is worth, perhaps it’s no surprise the law has weighed in – although legislators on either side of the Atlantic have reached different verdicts.
Since the 1880s, Europe’s Berne Convention has defended artists’ right to protect their work from “distortion, mutilation or other modification”. So to a litigious artist, well-meaning conservation could be “other modification”. In contrast, the US (VARA), passed in 1990, stated that “the modification of a work of visual art which is the result of conservation… is not a destruction, distortion, mutilation, or other modification”. That means conservation depends not just on available technology but also on the law or ethics surrounding a repair.
“Conservation depends not just on available technology but also on law and ethics”
To pre-empt these issues, institutions increasingly rely on negotiations with living artists before acquiring one of their works. “At Tate we have a lengthy discussion around longevity and change,” says Ormsby. “Some artists want change to be evident. Others want preservation as much as possible.”
Sculptor Tom Claassen, for instance, solves issues around his use of highly degradable rubber by telling conservators how he makes his pieces, so they can remake them every 10 years. Remaking also underpins the approach to a giant cube of lard sculpted with her teeth that is part of Janine Antoni’s work Gnaw, which New York’s MOMA recasts for every exhibition using moulds replicating Antoni’s bite.
Other artists explicitly challenge the concept of conservation, such as painter Anselm Kiefer. His monumental canvases embody the chaos and destruction he saw growing up in Germany’s post-war landscape, using techniques such as attaching electrodes to paintings with metallic content to bloom colourful oxides. Canvases are sent to galleries in full expectation that bits of them will fall off in transit. “It is not so easy having a painting of mine,” Kiefer once noted mischievously.
“Works are sent to galleries in full expectation that bits will fall off in transit”
The increasing use of technology-based media in art causes other issues around inherent vice, thanks to obsolescence and breakdown. Some artists acknowledge the issues and try to help. When the Tate group bought Michael Craig-Martin’s 2003 work Becoming – an endlessly changing computer-generated animation on an LCD screen – the artist provided its source code as a cornerstone for exhibition on whatever displays might be around in the future.
It’s not always so easy. Video Flag Z, created in 1986 by Nam June Paik, is a kaleidoscopic wall of 84 cathode-ray-tube TVs whose fuzzy pictures are integral to the work’s appearance. The old sets kept breaking down, and couldn’t simply be put in storage as they need periodic powering up to keep the diodes going. After initially scrambling to buy old CRT sets, conservator John Hirx decided emulation was the only sustainable answer, making new sets that try to capture the look and feel of the old.
Challenges like his, and that faced by the Tate team after the Rothko vandalism, show that even the best-laid conservation plans cannot anticipate all problems, or which scientific advances will prove most useful in solving them.
In the meantime, perhaps it’s best to just enjoy art as a manifestation of human creativity, however it is made or displayed. “I would never advise an artist not to use ephemeral media, or a curator not to acquire the work,” says Glenn Wharton. “If art production was driven by durability alone, everything would be carved in granite. What a boring world that would be.”
See more conservation rescue missions in our gallery: “Inherent vice: Saving masterpieces from destruction“
The real deal?
Tools similar to the ones conservators use to save artworks from damage and decay (see main story) can be used to discern fakes. Take the works of 20th-century forger Han van Meegeren, who notoriously painted in the style of 17th-century Dutch master Jan Vermeer. His efforts were so good they were proclaimed genuine by experts in the 1930s.
The truth came out when van Meegeren was accused of selling a Vermeer to the Nazis. Facing jail or even execution for treason, he admitted that this painting, and several others, were fakes. Van Meegeren died soon after.
Knowing his pictures would have to withstand certain tests available at the time, van Meegeren used genuine 17th-century canvas and pigments. But technology eventually caught up with him. As recently as 2011, gas chromatography and mass spectrometry (GC-MS) – thought to be by Dutch master Dirck van Baburen – was a van Meegeren.
Tiny paint samples from it were dissolved, then injected into a stream of gas and forced through a thin, heated tube. This broke them down into component chemicals, analysis of which revealed the modern-day material Bakelite. It had been added to the oil paint because the mixture, when heated, hardens to give the impression of great age. The advent of GC-MS turned a previously undetectable forger’s technique into a finger of guilt.
This article appeared in print under the headline “State of the art”
