Figuring out what killed crazy Caravaggio
Jun24

Figuring out what killed crazy Caravaggio

“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. The experience didn’t reign in Caravaggio’s predilection for violent fights. According to Cornaglia: “The artist’s last years were spent desperately running from one city to another. After stopping by Naples, he travelled to Malta, only to get into trouble after yet another brawl. Caravaggio was imprisoned by the Knights in August 1608 and later expelled from the Order “as a foul and rotten member.”… After some time spent in Sicily, unknown assailants attempted to murder Caravaggio in Naples, succeeding in disfiguring his face… Contemporaries described the artist as a madman during this time, exhibiting increasingly strange behavior and exploding into a violent rage at the slightest provocation.” Digression: some researchers have wondered if Caravaggio’s inherent aggression was being exacerbated by lead poisoning, as the dude actually ATE off of...

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Was antiquity really so tacky?
May20

Was antiquity really so tacky?

The ancient Greeks did it, and now the Phoenicians too. Over the past few years, it’s become increasingly clear that many of the white marble statues from Greece’s golden era were originally painted in garish colors. The discovery of pigment residues on a multitude of classical era sculpture has been a boon for lovers of kitsch and a downer for pretty much everybody else. Yeah yeah, I know it’s good to know The Truth, and it is fascinating that they had such bad taste but, well… Sigh. So it turns out that the Phoenicians, an ancient Semitic seafaring civilization who traveled around the Mediterranean from about 1500 BC to 300 BC, also painted and gilded their carvings. The Phoenicians invented an alphabet later adopted by the Greeks. One wonders if the Greeks also got their predilection for painting sculptures from the Phoenicians? A team of French and German researchers analyzed the surface of several Phoenician ivory sculptures held at the Badisches Landesmuseum Karlsruhe, in Germany, and found metal traces corresponding to ancient pigments and (gold) gilding. These metal traces are invisible to the naked eye, but can be detected using a technique called X-ray fluorescence. Ina Reich, the lead researcher of the Analytical Chemistry paper reporting the discovery, says she’s also found the same type of metal residues on Phoenician pieces at the Louvre–work which will be published elsewhere in the future. (I wrote a more science-y news article on the discovery here.) For the lovers of nanoscience out there, here’s a teaser: Reich also mentioned that some of the traces of leftover gold from Phoenician gilding had formed curious gold nanoparticles on the surface of the ivory after spending centuries underground. Reich is currently analyzing the gold nanoparticles, which she says would be impossible for forgers to emulate and thus may be a new cool new way to authenticate Phoenician...

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Photo fraud: eBay to the rescue!
Feb25

Photo fraud: eBay to the rescue!

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. It turns out that researchers wanting to authenticate a photo spend a lot of time scrutinizing the paper on which it has been printed, because photo paper generally provides the best dating and provenance clues. For example, researchers look for chemicals called optical brighteners which were added to all photo paper to brighten images starting in the 1950s. If a photo is purported to have been made earlier than the 1950s, then it can’t have any optical brighteners in the photo paper. Likewise, in the 1880s, companies started adding a so-called baryta layer to the top of photo paper as a physical barrier between image and paper, so trace impurities in the paper wouldn’t leach into the image layer and wreck the picture. Each company used a different ratio of barium and strontium in the baryta layer, and companies also changed these ratios over time. Since most photographers were loyal to a particular photo paper brand, authenticators check to see whether a suspect photo has barium and strontium ratios that correspond to the photographer’s preferred company during the era when the photograph was supposedly printed. Of course to make these comparisons, you need an enormous database of reference photo paper, says Paul Messier, a photograph conservator who helped develop ways to authenticate Lewis Hine prints in one of the world’s first million-dollar photo fraud cases. “A switch flipped on when I was working on the Hine project,” Messier says. “I...

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The two Mona Lisas debate – Everybody take a breath now.
Feb14

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

“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. I found it a bit odd that the Mona Lisa Foundation didn’t name the scientist involved in the carbon dating or include him or her in the press material. So I called ETH’s media relations folks and was told that Hans-Arno Synal from the Laboratory of Ion Beam Physics had done the work based on an “unattributed sample without information of the origin of the material or the object where this sample came from.” The institute has now emailed reporters a statement that notes: “Conclusions on origin or authenticity on the object from which this sample may originate cannot be drawn from this result only.” Of course, the Swiss Mona Lisa Foundation claims that there is other scientific evidence to support the idea that the young version of the portrait was made by da Vinci. For example, in a press release they note: “Previously, four tests undertaken by Prof. John Asmus, nuclear physicist, who digitised the brushstrokes of both paintings, established scientifically that both the ‘Earlier Version’ and the ‘Mona Lisa’ in the Louvre would have been executed by the same artist. This brushstroke analysis identifies conclusively an artist in the same way that DNA or fingerprints identify criminals.” This is a rather breathless claim too. I mean, the brush stroke research certainly suggests that the artwork is consistent with being da Vinci’s–or somebody who used his brushes, and liked his style so much...

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Fake crystal Aztec skulls
Jan30

Fake crystal Aztec skulls

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. To prove the two skulls were fakes, the researchers assembled some legitimate crystal Aztec artifacts. Then they used scanning electron microscopy to study the surface of both real and suspect crystal objects. Turns out that the surface of the real artifacts have irregular etch marks, a sign that the pieces were carved with hand-held tools. The suspect skulls have a patterned surface, a sign they were made with rotary wheel tools and hard abrasives. “Rotary cutting wheels were not introduced to stone workshops in Mexico until after the Spanish conquest of Mexico in 1521. The skulls therefore cannot be of Aztec manufacture.” Awesomely, the museum researchers noticed a small deposit of something unknown in the Smithsonian’s skull. Using x-ray diffraction they discovered that the deposit was silicon carbide, a synthetic abrasive only used in stone carving workshops starting from the mid 20th century onward. The Smithsonian artifact had probably been made shortly before it was sent anonymously to the museum. The researchers also had a closer look at the British Museum’s fake skull and discovered  green, worm-like inclusions in the rock. “Using Raman spectroscopy, the green inclusions were shown to be an iron-rich chlorite. These minerals are found in mesothermal metamorphic greenstone environments. Sources of this type are not found in Mexico or within the ancient Mexican trade network.” In fact, they are typical in rock crystal from Brazil or Madagascar. Wham bam. Interestingly, the report alludes to the fact that there are other crystal skulls around: “An increasing number of large and small quartz skulls have become known, particularly in recent decades.” Perhaps the owners should take a closer look at the surface etching of these...

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Star Trek Replicators, Dystopian Futures, And The #foodchem Carnival
Nov16

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… “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. I would like to point out that when a writer (that would be me) comes up with an awesome Star Trek parallel AFTER filing an article with her editor, said writer feels remarkably like she’s come up with a devastating comeback line exactly one minute too late to deliver it to her arch enemy. Luckily C&ENtral Science’s fearless leader Rachel Pepling started the #foodchem carnival this week, giving me an opportunity to slip my Star Trek analogy in to the public record. But seriously, I thought I’d use the carnival as a chance to make a few points about note-by-note cuisine that I couldn’t fit into my word count-limited print column for C&EN. If you haven’t read the piece, here’s a quick recap: 1. “Purveyors of note-by-note cuisine analyze the component chemicals of a finished dish, say a savory reduction sauce, which typically includes thousands of molecules from wine, broth, and other ingredients. Then they re-create the sauce using a subset of those molecules—namely the ones primarily responsible for our sensory experience of the sauce.” 2. Currently note-by-note cuisine can’t yet faithfully replicate your favorite foods. I tried a note-by-note orange cocktail and fish custard, and both tasted pretty awful. Or more precisely, the note-by-note dishes tasted like phantom food: recognizable but not substantial. OK, down to business: Several people have asked me why This calls the cuisine it note-by-note. The answer: He’s riffing off the idea of electronic music. Just like early electronic music producers compiled tunes note-by-note, This wants to make food chemical-by-chemical. Or chemical note-by-chemical note. Or note-by-note. Currently This is at the stage of working out the top-notes of a particular dish. Namely those big, important flavors, odors and textures that are absolutely essential if someone is to recognize fish custard as fish custard. Even though This is not yet focused on getting trace flavor compounds in to...

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