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Category → hindsight is 20-20

Art conservation that does more harm than good

The Night Watch by Rembrandt is one of thousands of paintings to receive the wax-resin treatment. Credit: Wikimedia commons

The Night Watch by Rembrandt is one of thousands of paintings to receive the wax-resin treatment. Credit: Wikimedia commons

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. Continue reading →

Dead Sea Scrolls – Scientists In Berlin Criticize Israeli Cultural Authorities For Treatment Of Sacred Documents

Dead Sea Scroll fragments from a current exhibit in Philadelphia. Credit: Darryl Moran/The Franklin Institute

Last week, a peer-reviewed journal called the Restaurator published a controversial article about the Dead Sea Scrolls written by two Berlin-based scientists who charge that these sacred documents are not receiving proper care from the Israeli cultural institutions responsible for their well-being.

The article’s abstract does not mince words:

“Examination of the properties of the scrolls proves that frequent travel, exhibitions and the associated handling induce collagen deterioration that is covered up by the absence of a proper monitoring program.”

“I want the scrolls to be protected,” says Ira Rabin, who co-authored the piece entitled “Dead Sea Scrolls Exhibitions Around The World: Reasons For Concern” with her colleague Oliver Hahn at the German Federal Institute for Materials Research and Testing.

The 20-page document specifically criticizes the Israel Antiquities Authority and the Israel Museum in Jerusalem, who hold responsibility for a majority of the Dead Sea Scrolls. Both defend their treatment of the scrolls (detailed below). Continue reading →

Arsenic Contamination Of Artifacts

This armadillo's hairy underbelly is not contaminated with arsenic. Credit: Sarah Everts

A few weeks ago I got to touch the hairy underbelly of an armadillo.

Even though it hadn’t been alive for some time, I was still pretty chuffed about the whole experience—I mean, it’s unlikely I’ll ever have such an intimate moment with an armadillo again.

The beast in question had been briefly removed from its basement cupboard home at the North Carolina Museum of Natural Sciences as part of a behind-the-scenes tour during the recent Science Online conference.

The experience of handling a stuffed armadillo was not just exceptional because it’s a stuffed armadillo. The experience was exceptional because it’s rather unwise to spontaneously handle animal or plant-based artifacts found in museum storage rooms.

Until the 1970s, many biologically-based artifacts were doused with arsenic (as well as lead, mercury and some organic pesticides such as DDT) to keep insect and microbial invaders at bay, explained Lisa Gatens, the NCMNS curator of mammals who let me and others on the tour touch the animal. (For the record, the armadillo was safe.)

Since the practice of adding pesticides to biologically-based artifacts began in the 1800s, there are an awful lot of contaminated museum artifacts out there. And many have levels of arsenic that could pose a problem to human health if handled without protection. 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 →

The Peculiar Life Of The Dead Sea Scrolls

A Dead Sea Scroll containing Psalms text. Credit: Wikimedia Commons.

After spending more than two thousand years in peaceful hibernation, the Dead Sea Scrolls (DSS) have had a rough six decades. Discovered in several dry caves near the Dead Sea from 1947 through 1956, the texts experienced a series of travel and conservation adventures that border on mishandling, says Ira Rabin, a staff scientist at Germany’s Federal Institute for Materials Research and Testing (BAM).

Rabin has published several scientific papers on the Dead Sea Scrolls, which have historical and religious importance because they contain early versions of the Judeo-Christian Old Testament as well as other important Jewish writings. I recently met Rabin at a cafe in Berlin, where she described to me the potpourri of treatments that these texts—most of which are written on animal skin parchment–have received since their discovery.

The Dead Sea Scrolls have been covered in castor oil and glycerin as well as plastic consolidants (the latter of which is particularly unwise because no plastic stays in good shape for more than a few decades). Other treatments include Fuller’s Earth, a clay-like material, and being attached to glass plates using adhesive tape.
Continue reading →

Plastics Denial Syndrome

Dutch artist Madeleine Berkhemer uses stockings in her art, which are made of nylon and spandex. Photo Courtesy of Berkhemer.

Sometime during the 1960s, artists en masse began using plastics to make art–a trend that continues today.

The problem is that many plastic polymers have a shelf life of just a decade or so, after which they begin to crumble or crack. Consider an old rubber band or a plastic bottle left out in the sun.

And just as bisphenol A leaches out of baby bottles and into the surrounding liquid, many of the components of plastic-based art seep out of the work, causing all sorts of unpleasant consequences (details below).

Furthermore, the short lifespan of plastic art is at odds with the fact that most museums want to buy art that lasts centuries or at least decades… not years.

Yet in the 1970s, 80s and early 90s, just as plastic sculptures and designer furniture were pouring in to museum and gallery collections, staff conservators were collectively sticking their heads in the sand about the inherent vulnerability of these objects… I mean, even though plastics have short lifespans, there are ways to extend them. But conservators weren’t acknowledging that plastics were problematic.

It’s come to be known as “the plastics denial syndrome” and thankfully it’s now over, says Yvonne Shashoua, a conservation scientist at the National Museum of Denmark, in Copenhagen. Shashoua features heavily in an article I just wrote about how plastics are a serious problem child for museum staff and what can be done to improve some pretty impressive bad behavior.

Yvonne Shashoua cares for a 1970s crash test dummy that is literally weeping plasticizer. Photo Courtesy of Shashoua.

Case in point: the phthalate plasticizer added to make PVC (polyvinyl chloride) maleable has a tendency to leach out, so much so that small pools of the plasticizer collect in and around the art. These plasticizer puddles are not precisely aesthetically pleasing, they attract dust and actually the loss of the plasticizer destabilizes the plastic making it vulnerable to cracking.

Then there’s this more nepharious example: Acidic gases percolate away from plastic objects made of cellulose acetate and then corrode nearby metals and textiles. For this reason conservators call cellulose acetate “the malignant plastic.”

Cases like these forced conservators to take the degradation of plastics seriously. Check out the longer article to find out what museum staff are now doing to keep plastic art and artifacts alive and as well-behaved as possible.

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 →

Digital Restoration: Introducing An Undo Function?

Removing plastic lamination from the Codex Eyckensis © IRPA-KIK, Brussels

Every once in a while, well-intentioned attempts to save a valuable painting or artifact from the decay of time bombs pretty badly. Consider the thousand-year-old ancient parchments that were laminated in the late 1950s or early 1960s–during that era’s love affair with plastics–in order to protect the valuable documents from the wear and tear of a long life. Four decades later, the yellowed and brittle laminate had to be painstakingly removed from Belgium’s oldest parchment, the Codex Eyckensis, as the decaying plastic began to exacerbate the injuries it had aimed to avoid.

Such hard lessons have since pushed conservators to look for easily reversible, minimally invasive ways to protect or restore cultural masterpieces—sometimes opting to shun any interventions altogether. Another possibility is to consider a digital restoration technique that offers “all the benefits of an Undo button,” says Daniel Aliaga, a computer scientist at Purdue University.

Digital restoration of a Mexican Casas Grandes vessel. Credit: Daniel Aliaga.

Aliaga and his Phd student Alvin Law have designed software that can project light images on to sculptures or paintings that, for example, can reveal to the viewer what the decaying masterpiece may have looked like before decades or millennia of deterioration. The projection can also boost faded colours on a painting or touch up decorative tints on a piece of pottery or a sculpture’s exterior. Turn off the projector, and the piece reappears in its current day form.