Visiting The Metropolitan Museum’s Science Lab
Jun06

Visiting The Metropolitan Museum’s Science Lab

I recently passed through New York City and had the excellent opportunity to tour the laboratories beneath the Metropolitan Museum of Art with Marco Leona, who’s been the museum’s head of scientific research since 2004. “We deal with everything under the sun, that’s been under the sun for the last 5000 years or so,” he told me. The Met's 20-person scientific team has a professional familiarity with New York’s real-estate squeeze. Their equipment is split among four labs in the Met’s Upper East Side neighborhood. Each lab corresponds to one of the museum’s four main artifact conservation departments: paintings, textiles, works-on-paper and “objects,” which is literally everything else--from metal sculptures to ceramic mosaics. Leona picked me up at the Fifth Avenue security desk on a Monday, when the museum is closed to the volumes of people who normally pack its halls. We walked unusually effortlessly through the European Sculpture and Decorative Arts exhibit to a special elevator that brought us down to the basement “objects” research space. Wandering around lab benches full of beautiful artifacts, Leona gave me an overview of the science team’s many projects. They’ve worked on everything from how acetic acid wafting off degrading ancient Egyptian wood can accelerate the corrosion of nearby metals to how researchers might use biomedical tools, such as antibodies, to study cultural heritage objects. There’s excellent logic for using antibodies: In many ancient objects, paint pigments are often suspended in paint binders that are composed of biologically-sourced materials such as egg white, plant sap, animal collagen or mixtures of all these and more. Identifying the presence of a single, specific type of biological building block, such as an egg white protein, in a complex paint mixture is really tricky. But antibodies have evolved to do exactly this. At every moment of our lives, antibodies are scouring our blood looking for specific proteins on pathogenic bacteria so that our immune system can then destroy them. It’s possible to tune antibodies to search for biological components of paint instead of naughty bacteria. Scientists in Leona’s team also develop ways to better conserve and authenticate artifacts. For example, when the Neptune Pendant, a Renaissance jewel in the Met’s collection was suspected of being a 19th century fabrication, Leona’s team came to the rescue. They dated enamel samples from all over the pendant and found that there were both 16th and 19th century components. The conclusion: the Neptune pendant was probably a Renaissance piece that got a facelift in the 19th century. (As an aside this "facelift" was likely orchestrated by Germany’s infamous art dealer Frédérick Spitzer who apparently hired artists from Cologne to Paris...

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Metals And Their Corrosion
May25

Metals And Their Corrosion

There's a double hit of interesting metal artifact research news this week. The first discovery comes from researchers in Lyon, France, who wanted to answer a contentious question in European historical economics: Did an influx of silver coins from Central and South America cause a period of crazy high inflation in Europe during the years 1520-1650--an episode known as the Price Revolution? Yeah, I hadn't heard of it either. But according to Lyon’s Anne-Marie Desaulty, it’s a seriously controversial topic in historical circles. Remedying this controversy could seem relatively simple: 1. Find some coins used Western Europe during this inflation era. 2. Check their chemical make-up to see if they originated from mines in Europe or mines in the Americas. If the metal originated in the Americas then it would be safe to blame Europe’s inflation on Spain’s accumulation and distribution of silver from the colonies. In principle, science can answer this question because metals from mine ores in different geographical regions often have their own unique chemical fingerprint. This fingerprint is called the isotope ratio: For silver, it would be the relative abundance, in the mine ores, of silver atoms that have 60 versus 62 neutrons in their nuclei. Unfortunately for this inflation controversy, different silver isotopes are really hard to tell apart analytically. OK, fine. Instead researchers could try comparing isotopes of lead, which is another element present in silver ores and is thus is also found--in trace amounts--in silver coins. Except unfortunately lead isotope ratios are quite similar in Europe and the Americas—a tad too similar to conclusively distinguish the provenance of coins through lead isotopes alone. Oi. So researchers might then be tempted to look at isotope ratios of copper which was added to the silver coins to improve their hardness. But scientists have to be wary of drawing too many conclusions from copper isotope analysis of silver coins because the copper might not have originated from the same place that the silver was mined. With so many caveats, I might be tempted to give up on the project. Undaunted, Desaulty’s team first figured out how to use a recently improved technology to distinguish silver isotopes (which is incidentally called Multi-Collector Inductively Coupled Plasma-Mass Spectrometry, oh yes!). And then they combined these silver results with their copper and lead isotope measurements. Examined together, the data allowed the researchers to conclude that Spanish money originating in the Americas did not cause the inflation. Desaulty says that it wasn’t until 1700s, after the Price Revolution, that Spanish coins from the Americas exploded into the European marketplace. I imagine there's a group of economic historians somewhere in this...

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