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A brief hiatus: Onwards to Uzbekistan

Registan, Samarkand, Uzbekistan. Courtesy Wikimedia Commons

Registan, Samarkand, Uzbekistan. Courtesy Wikimedia Commons

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!

This gold gilding at the Reales Alcazares of Sevilla was added in the 19th century.

This gold gilding at the Reales Alcazares of Sevilla was added in the 19th century.

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.

Cross section showing gold gilding on top and yellow lead chromate paint below.

Cross section showing gold gilding on top and yellow lead chromate paint below.

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!!)

This 7th century BC amber found in an Italian tomb originally came from the Baltic area even though Italy had its own sources of amber.

This 7th century BC amber found in an Italian tomb originally came from the Baltic area even though Italy had its own sources of amber.

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.

There’s also an analysis of medieval Hungarian silver coins, and several papers on the effects of pollution and humidity on cultural heritage objects, from ancient architecture to antique books.

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.

But perhaps the most interesting read in the inaugural issue of Heritage Science

is the very pointed essay by journal editor Richard Brereton.

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.

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.

The tomb of Richard I’s heart in Notre Dame of Rouen, France. Credit: walwyn—professor-moriarty.com

The tomb of Richard I’s heart in Notre Dame of Rouen, France. Credit: walwyn—professor-moriarty.com

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 →

Ancient Roman cosmetics: Skin cream from the 2nd century A.D.

Roman skin cream from the 2nd century A.D. found in a temple below London Southwark. Credit: Nature

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.”

Recreated cream. Credit: Nature.

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.

Star Trek Replicators, Dystopian Futures, And The #foodchem Carnival

Over here at C&ENtral Science, we’re celebrating Thanksgiving with a food chemistry blogging carnival. Artful Science will return to regularly scheduled programming after we manage to digest all the turkey…

Jean Luc drinking his signature tea

“Tea. Earl grey. Hot.”

I never gave much thought to Jean-Luc Picard’s quintessential beverage request from the Star Trek The Next Generation replicator machine until last week.

I was talking with some friends about an article I had just filed with my editor about note-by-note cuisine. It’s the new passion of Hervé This, one of the co-founders of molecular gastronomy.

As I was describing This’ idea of creating food from chemical scratch, one molecule at a time, I suddenly realized that this is pretty much what Picard’s replicator machine had been doing all along on the Enterprise. 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 →

100-Year-Old Sacred Congolese Statues Have Digestive Tracts

This statue has legitimate plumbing. From the Indy Star's Robert Scheer. indy.st/IovdDI

The headline pretty much says it all.

If you aren’t a regular reader of the Indianapolis Star, you may have missed this awesome article about how sacred statues sculpted by the Songye people contain carefully dug out digestive tracts.

The Songye people, who live in the Democratic Republic of Congo, use the statues in fertility and war ceremonies.

Experts had long known that the priests inserted materials in to the statues’ mouths and other orifices “to enhance the figures’ magico-religious powers,” said Richard McCoy, a conservator at the Indianapolis Museum of Art, to the Indy Star.

For example, McCoy said the statues had food, dirt struck by lightning and the teeth of albino men stuffed in their orifices.

But nobody expected a fully carved digestive tract inside the figures, McCoy told the Indy Star.  ”We were blown away.”

McCoy made the discovery when he put a 100-year-old Songye figure in an X-ray machine. After the initial discovery in 2006, he started visiting other museums to see if these digestive tracts are common.

And indeed they are: He discovered that some 42 Songye statues have carved out digestive tracts.

McCoy has now graduated from studying the digestive tracts in two-dimensions (using X-ray images) to studying the figures in three-dimensions (using computer tomography, or CT scans).

It’s not the first time conservation scientists have used CT to look at artifacts. They’ve used the technique for years to investigate cultural heritage objects ranging from ancient Egyptian cat mummies to 17th century globes of the world.

Stinky, Degrading Film And How To Stop It

Moldy Movies. Credit: Analytical Methods

Like humans, fungi have a taste for old movies. The problem is that they like to eat the film rather than watch it.

Adding insult to injury, fungi produce copious amounts of stinky odors from their consumption of classic flicks.

In fact, this fungi flatulence can cause headaches, nausea and irritated eyes in humans. (In particular, one airborne fungal molecule called 1-octen-3-ol.)

For this reason film archive staff fear any sort of mold on film reels: It means their precious collections are being destroyed by fungi.

Furthermore the fungal digestion produces smells that can make conservators sick.

That’s why the UK’s North West Film Archive approached researchers at Manchester Metropolitan University (MMU) to ask if there was any way to build a machine to detect the problematic odors.

Last week, MMU’s Craig Banks and his collaborator Gavin Bingley reported a handy new mold flatulence detection device.

With such a machine, conservators can test film reels donated from attics and basements. Sometimes these donations are so thick with dust it is hard to distinguish from mold—unless conservators take a sample and try growing it in a lab, Banks says. (Which then means the conservators may be exposed to the stinky molecules they’d much rather avoid.)

Another benefit of the device: If invasive fungi manage to sneak into storage areas, the detector can forewarn conservators about the moldy intruders before the growth gets out of hand—or is visible to the naked eye.

It’s worth pointing out that even if mold is kept at bay, old degrading film produces its own special brand of harmful flatulence. Continue reading →

Banking On A Bunker To Save Britain’s Film

Cellulose nitrate degradation that the BFI aims to avoid with their new archive. Credit: BFI

If I had to marry an inanimate object, I would not choose the Berlin Wall as Eija-Riitta has, but I might be tempted by a bunker, possibly the Boros bunker, whose dark history has been reclaimed by great art.

So you can imagine that I was super interested in a recent Guardian article about a new archive for the British Film Institute, which will be located on top of the site of an old nuclear bunker.

The BFI is facing what’s already a become a major problem for many who possess collections of early cinema: How do you keep 450,000 cans of film from breaking down, particularly when the film is made of cellulose nitrate, a plastic not known for its longevity?

When cellulose nitrate breaks down, it causes the release of nitric acid, which can accelerate degradation in nearby film. Eventually all the degradation results in a gooey or powdery mess where there was once a fantastic film.

The BFI’s spokesperson Brian Robinson told me that in the new archive, fragile film will be kept at -5 C, which is “down a notch” from the previous temperature (3-4 C) that the film was stored at. According to studies done at the BFI, Robinson says that the cellulose nitrate degradation will “be arrested.”

I can’t imagine that it’s ever possible to completely arrest degradation, but I’m guessing the drop in temperature seriously decreases the rate of chemical breakdown.

Finally, Robinson says the new £12 million facility will be well-ventilated, which I presume will suck away any amount of nitric acid that has managed to percolate off the valuable film.

Are Crop Circles Made By Microwaves?

Made by microwaves? Credit: Newscom.

If you believe that crop circles are a form of art made by rogue (human) sculptors, then you’ll probably want to read Richard Taylor‘s fascinating piece in Physics World about the science of making these curious farmland imprints.

If you can’t get past the PW paywall, check out my column in this week’s Newscripts about his quirky work on crop circle science.

In particular, Taylor thinks artists are using hand-held microwave magnetrons (I kid you not!) to make modern-day crop circles and he comes up with a pretty convincing argument to back up his sci-fi-sounding theory.

Conspiracy theorists may not buy Taylor’s logic since it doesn’t involve aliens (they’ve already accused Taylor of being in cahoots with US, UK and German spy agencies). But I like the microwave theory as much as the one proposed by Australian’s attorney general: that stoned wallabies are making crop circles in poppy fields down under.