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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 →

Figuring out what killed crazy Caravaggio

Caravaggio's The Crucifixion of St Andrew, made in 1607 when the artist was on the run. Credit: Wikimedia Commons

Caravaggio’s The Crucifixion of St Andrew, made in 1607 when the artist was on the run. Credit: Wikimedia Commons

“Caravaggio’s life was even darker than his paintings.”

This is how Italian microbiologist Giuseppe Cornaglia began an account of his uphill battle to figure out what microbial pathogen may have killed the famous and violent 16th and 17th century Italian painter, who died under rather curious circumstances in 1610.

Cornaglia is part of a growing number of researchers who look into the dental pulp of skulls found in graves, in search of DNA from ancient pandemics. The field is called paleomicrobiology, and it’s been used to figure out what microbes caused the Plague of Athens, which indirectly helped Sparta topple Athens in the Peloponnesian War, and which in turn instigated the decline of classical Greece.

Paleomicrobiology has also been used to show that tuberculosis was already in the New World before Columbus showed up carrying a host of other deadly pathogens on board.

So, given that Caravaggio died under strange circumstances (more on that in a second), Cornaglia wanted to look at Caravaggio’s remains and see if he could detect the presence of a deadly pathogen in the artist’s dental pulp. Dental pulp harbors the DNA of microbes present in the person at death. The pulp tissue is covered by protective enamel so that contamination from other microbes can’t occur during the intervening centuries, before forensic researchers dig up the skeleton and crack open the tooth.

The first problem Cornaglia faced was that he didn’t know where Caravaggio’s remains could be found.

This is not entirely surprising when you learn more about the painter.

Caravaggio was an angry guy and quick to pull out his sword. During a fight in 1606, at age 35, he tried to castrate his opponent during a street brawl in Rome, Cornaglia said. The castration was successful. But it also killed Caravaggio’s foe, leaving Caravaggio with a murder charge and a life on the run. Continue reading →

The two Mona Lisas debate – Everybody take a breath now.

The two Mona Lisas: Left: the putative young upstart. Right: The Louvre Classic. Credit: Mona Lisa Foundation

The two Mona Lisas: Left: the putative young upstart. Right: The Louvre Classic. Credit: Mona Lisa Foundation

“The Mona Lisa Foundation’s mission is to make Leonardo’s ‘Earlier Mona Lisa’ known and loved in its own right, as much as the version that hangs in the Louvre Museum.”

This quote comes from the website of a Swiss organization that sent out a press release yesterday announcing it had new scientific proof that a painting of a younger looking Mona Lisa is the first portrait da Vinci made of the famous muse.

And a maelstrom of news followed.

But let’s just be clear about this new scientific proof: It’s the radiocarbon dating of a piece of cloth canvas.

New tests at the Swiss Institute for Technology in Zurich (ETH) suggest the canvas cloth was made between 1410 and 1455. Previous dating experiments at Oxford pointed toward the 17th century, which implied the painting was not made by da Vinci, who lived between 1452 and 1519.

Since the canvas cloth date just needs to fall before the production of the painting, the new carbon dating does lend credence to the claims that the artwork could have also been made by da Vinci.

But it’s JUST the dating of the cloth, folks: There’s no proof in the current study that da Vinci actually made the painting. Continue reading →

When a Rembrandt copy is not a forgery

Top: The original. Middle: The mock-up. Bottom: Mock-up & portrait below.  © J. Paul Getty Trust

Top: The original. Middle: The mock-up. Bottom: Mock-up & portrait below. © J. Paul Getty Trust

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 thing.

The military borrows from cultural heritage science.

This illuminated manuscript has helped out the US army’s remote sensing. ©Lorenzo Monaco, Praying Prophet, National Gallery of Art, Washington, Rosenwald Collection

Civilian society constantly makes use of aerospace and military inventions:

Can anyone say the Internet? Or transparent braces? (These nearly invisible dental devices are made from a material called polycrystalline alumina, which was initially developed by NASA “to protect the infrared antennae of heat-seeking missile trackers,” notes Discovery.com)

Cultural heritage also borrows from NASA: Portable X-ray fluorescence spectroscopy (XRF) was developed for MARS missions, so that roaming rovers could assess the chemical make-up of rocks on that planet.

Now XRF is a must-have tool for conservation scientists, who want to analyze the chemical composition of art that cannot be transported into a lab, such as a cave painting or Renaissance fresco.

But what about reversing the direction of technology export, so that cultural heritage scientists return the favor by developing new analytical tools for art research that then get delivered to the greater world of science?

This has not happened—until now*. Continue reading →

Weeping Paintings

Otto Piene’s Harvest began to shed white tears in 2000, seven years after it was completed. Credit: ICOM-CC publications.

You don’t really expect a seemingly dry painting to suddenly start oozing streaks of wet paint, seven years after its completion.

So when Otto Piene’s Harvest, which was finished in 1993, began to weep white paint in 2000, owners, conservators and the artist were all rather surprised.

Although Harvest is Piene’s only work to start weeping, the strange liquefying process has happened to dozens of other artworks from contemporary artists as varied as Jonathan Meese and Frank von Hemert, explains Jenny Schulz, a conservator in Cologne, Germany, who’s made it her business to figure out why. “It’s quite a common thing,” she says.

Taking a closer look at several of these paintings, Schulz figured out something that all the weeping paintings had in common: The tears occurred in places on the canvas where the artist has laid down a thick layer of oil paint.

A close-up of the tears from the thick, white base layer on Harvest by Otto Piene. Credit: ICOM-CC publications.

Although the thickly-laid paint seems to dry, it turns out to be unstable and capable of liquefying. But why? It’s not as if applying thick layers of oil paint is a new thing among artists… Yet the weeping painting issue is relatively new, having emerged in the last two decades or so.

What’s changed, Schulz says, is formulation of oil paints. Until recently oil paint was made using linseed oil. But the problem with linseed, she says, is that it has a tendency to yellow over time.

So paint formulators began exchanging linseed oil for sunflower oil, because sunflower oil doesn’t yellow.

The problem is that sunflower oil doesn’t dry as well. That’s because the oil contains fewer reactive double bonds, which are required to form a permanently dried paint complex, Schulz says.

Thick layers of the sunflower oil paint may seem to dry, but they are unstable. Subjected to changes in temperature and humidity or even the jostling that occurs during transport, these layers can collapse, releasing component parts as a gooey tear running as fast as 2 centimeters per month. Continue reading →

Dear eBay, I Love You. Sincerely, Conservation Science

Measuring Barbie headspace: Namely, the smells coming off their PVC plastic bodies. ©M. Strlic

Dear eBay,

I love you.

Yours Sincerely,
Conservation Science

I’ve been conducting a rather unconventional poll.

It consists of a single question posed to unsuspecting conservation scientists, typically during conference coffee breaks or at the hotel bar thereafter:

“Um. So have you ever bought anything on eBay… I mean, for your scientific work?”

What’s amazing is that researchers working with cultural heritage objects as diverse as Picasso paintings, plastic sculpture & toys, and digital art have all answered “yes.” Continue reading →

Fashion Fights In The 1600s: Parents Just Don’t Understand Their Kids’ Clothing Styles

Flinck’s final portrait of Dirck (left) compared to the more fashionable original (right). Courtesy of van Eikema Hommes

Fashion trends come and go but one thing stays the same: Kids and parents often don’t see eye-to-eye on style.

Even in 17th-century Amsterdam.

A great example of this was recently unearthed by University of Delft researcher, Margriet van Eikema Hommes, when she took a closer look at paintings by the Dutch artist Govert Flinck.

Flinck was a pupil of Rembrandt, but he had more commercial success than his teacher.

Case in point: When Amsterdam’s new town hall was built in the mid 1600s, it featured several Flinck works but only one by Rembrandt, and this lone Rembrandt painting was removed after a year, van Eikema Hommes says.

Flinck’s success was probably due to his strong familial connections to Amsterdam’s wealthy Mennonite community, who became his regular patrons. And therein lies the interesting historical fashion-friction.

It turns out that Amsterdam’s Mennonite community favored solemn, dark outfits. Meanwhile 17th-century cool kids wore colorful tights. (Much as modern-day hipsters opt for brightly colored stockings…)

In fact, some members of the Mennonite congregation would strike out against members who wore less conservative, fashionable clothing—clothing that the Mennonites considered indecent, van Eikema Hommes explains.

Against this cultural backdrop, Flinck was asked to paint a portrait of his young Mennonite nephew Dirck. If you look at the final version of the portrait from 1636, the nephew looks pretty much like a conservative young Mennonite.

But looks can be deceiving. Continue reading →