My apologies for a few weeks hiatus over here at Artful Science.
Last summer I got married and we are finally off on our honeymoon to Uzbekistan (aka the honeystan) where we will explore some awesome Silk Road architecture.
Given that we’ll be looking at a lot of mosaics, I thought I’d point you to this post on the conservation of tile art and the 2011 Nobel Prize in chemistry.
See you at the end of April…
Gold gilding, ancient amber and a mysterious hidden sculpture: A new cultural heritage journal launches!
There’s beautiful gold gilding at Reales Alcazares royal palace in Seville, Spain.
Yet it turns out that the pretty gold gilding you see in the image on the left is not precisely original.
The World Heritage Site was originally built in 914 AD, and then expanded from the 14th to the 16th century.
Recently, Spanish researchers found a layer of paint lying below the gold gilding that contains lead chromate, a pigment that wasn’t used until the 19th century. So the gold lying above must have been added afterwards.
Yellow lead chromate pigment is responsible for the bright color of many old school buses, and it was even used as a colorant for yellow candy before falling out of favor because both lead and chromate are extremely toxic.
Spanish researchers report that the lead chromate layer was added sometime after 1818 above a deteriorated layer gold gilding, probably as part of a 19th century restoration project.
The lead chromate may have been painted on as false gold to keep up appearances before new gold gilding could be applied.
Or it’s possible that the lead chromate was painted on just before the new gold gilding: The paint may have acted as a foundation layer to help the new gold gilding adhere.
This conundrum is reported in the inaugural issue of Heritage Science, the first peer-reviewed journal to focus entirely on cultural heritage science. (Welcome!!)
There’s a variety of interesting topics reported in the journal’s first edition, including a way to determine the geographical origin of amber which provides clues about early trading roots of the fossilized tree resin.
The issue also contains a cool paper about a sculpture accidentally discovered behind a wall of St Petersburg’s Winter Palace in 2010.
The sculpture, called Fugitive Slave and made by the Russian artist Vladimir Beklemishev, was inspired by the anti-slavery novel Uncle Tom’s Cabin. It was initially exhibited at the World’s Fair in Chicago in 1893, and then sent to Russia before being hidden in the palace wall after the sculpture suffered heavy damage during World War Two.
The sculpture was made to look like bronze, even though it is definitely not bronze.
That’s why the scientists are keen to study its make-up: The pseudo bronze involves creative use of gypsum, iron, copper and arsenic.
Brereton does not mince words about the devastating effect of 20th century progress on cultural heritage. He begins with his hometown of Bristol, where “post-war planners destroyed more of Bristol than [World War 2] bombs” and goes on to decry lost heritage in other parts of Europe, Asia and the Americas.
“Capitalists, aristocrats, democrats and communists were all at it in the twentieth century, destroying a heritage that had evolved very slowly for centuries. In the past there had been waves of localized destruction, for example in Rome, the Popes raided marble from the Coliseum in order to construct new churches, and in Latin America, the Spanish conquistadors organised a mass destruction of Inca, Aztec and many other cultural artefacts – for example there are only fragments of Aztec written texts available due to the enthusiastic destruction of material by priests. But the twentieth century appears unique for a mass international desecration of our global historic heritage. Most governments were dependent on some sort of political support, even tyrants have to feed their armies, and people wanted hot water in the homes and good food on the table and washing machines and televisions rather than fine paintings and important buildings.”
Here’s to reading more in Heritage Science about how 21st century science can inform efforts to conserve what’s not been destroyed in the 20th century.
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. Continue reading →
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. Continue reading →
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. Continue reading →
“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 →
There’s a great report out about how the British Museum and the Smithsonian teamed up to prove that two crystal skulls, one at each museum, are actually fakes.
Both skulls were purportedly made by Aztecs in Mexico prior to Columbus’ arrival. The British Museum bought its skull from Tiffany and Co. in 1897 while the Smithsonian received its skull in 1960 from an anonymous donor.
Although skulls are common motifs in Aztec art, museum curators at both institutions were suspicious of the skulls for a couple of reasons.
For one, neither skull comes from well-documented official archaeological excavations.
Also something was weird with the teeth.
To quote the report: “The rigid linearity of features representing teeth contrasts with the more precise execution of teeth on pre-Columbian artefacts.”
It sounds like whoever faked the crystal skulls was a little too fond of idealized, modern dentistry. Continue reading →
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.
Last week, while working on an article about the chemical make-up of 2000-year-old medicine tablets from a Roman shipwreck, I read that back in 2003 archeologists had unearthed a full canister of cosmetic skin cream, hidden in a Roman temple drain in Southwark, London.
When a Museum of London curator opened up the 2nd century A.D. canister, she found it full of white ointment, awesomely reminiscent of modern-day Nivea cream.
This rare find was then chemically analyzed by University of Bristol’s Richard Evershed, who has a quirky research niche: Figuring out the composition of ancient medical, food and cosmetic concoctions, usually by studying residues leftover on old pottery. (He made news last December by reporting that the fatty deposits on pieces of ancient Polish pottery are Northern Europe’s oldest evidence of cheese-making.)
So what precisely was in the creamy white ointment?
In a 2004 Nature paper, Evershed’s team announced that “the Londinium cream” was primarily made up of animal fat, probably from cattle or sheep. They also detected starch, which was likely isolated by boiling roots and grains in water. In addition, the cream contained a tin dioxide mineral called cassiterite with the chemical formula SnO2.
Then came some reverse engineering. Evershed’s team mixed together a new cream based on the proportions of animal fat, starch and tin dioxide that they had measured in the ancient ointment. Here’s how they describe its aesthetic appeal:
“This cream had a pleasant texture when rubbed into the skin. Although it felt greasy initially, owing to the fat melting as a result of body heat, this was quickly overtaken by the smooth, powdery texture created by the starch. Remarkably, starch is still used for this purpose in modern cosmetics. The addition of SnO2 to the starch/fat base confers a white opacity, which is consistent with the cream being a cosmetic. Fashionable Roman women aspired to a fair complexion, and the Londinium cream may have served as a foundation layer.”
The researchers go on to say that employing tin to color the ointment white would have been safer than using toxic lead-based pigments, which was common in that era. “White Roman face paint typically comprised lead acetate, prepared by dissolving lead shavings in vinegar.”
They write that it’s not clear whether the cream’s maker intentionally opted for tin because it is non-toxic compared to lead. During the 2nd century A.D., Roman society was slowly becoming aware of lead poisoning… But then again, the chemists of that era weren’t very adept at distinguishing lead from tin, note the authors.
Another possibility is that the cosmetic-maker used tin out of convenience, because nearby Cornish mines had abundant deposits of tin dioxide. Or perhaps our cosmetic-maker was an early pioneer of the buy-local scene.
From The CENtral Science Blogs
- May 23rd, 2013By Jeff Huber
- May 22nd, 2013By Melody Bomgardner
- May 20th, 2013By Jyllian Kemsley
- May 20th, 2013By Sarah Everts
- May 17th, 2013By Carmen Drahl
- May 13th, 2013By Lisa Jarvis
- Apr 23rd, 2013By David Kroll
- Apr 18th, 2013By Glen Ernst
- Mar 11th, 2013By Rick Mullin