Category Archives: From Conservation

ImaginAsia: The Lost Finger

Guardian figure; Japan, Kamakura period, 1185–1333; wood (Cryptomeria japonica); Purchase—Charles Lang Freer Endowment, F1949.20

Guardian figure; Japan, Kamakura period, 1185–1333; wood (Cryptomeria japonica); Purchase—Charles Lang Freer Endowment, F1949.20

All was still, absolutely still as the moon rose over the National Mall in Washington, DC. The visitors had left, and the Freer|Sackler was eerily quiet. A shaft of moonlight pierced the museum’s skylights and flooded over the Japanese guardian figures standing proudly in the hallway. Under the magic of the moon, the figures slowly came to life. Towering over mere mortals and rippling with muscles, the guardians were an intimidating sight. In their earlier history, the figures stood guard in front of a Buddhist temple, but that night they battled fierce demons to defend the art collections of the Freer|Sackler.

The next morning, one of our security officers noticed a finger belonging to the guardian figure pictured above resting on its pedestal. It must have been a fearsome fight . . .

Well, OK, that’s probably not exactly how it happened. The only thing we know for sure about that incident in April 2009 is that the security officer found the finger and called me, Ellen Chase, objects conservator. At the Freer|Sackler, we do have figures who fight to defend the collection—but we aren’t made of wood (and we have much smaller muscles). We work in the Department of Conservation and Scientific Research.

The Freer|Sackler Objects Lab.

The Freer|Sackler Objects Lab.

Please Don’t Touch
When you go to museums, there often are a lot of “Please don’t touch” signs. But why? It’s because art is a lot more fragile than it seems. The guardians are so big that it is hard to imagine they are delicate, but the wood is at least six hundred years old and can be brittle. Instead of being sacrificed during a brutal fight to defend the museum, the finger more likely was knocked off by a visitor who got too close.

Besides the risk of breaking off a piece, there are a few really big reasons why we ask you to not touch the art:

  1. Touching an artwork just one time doesn’t seem like it would have much impact. But each time someone moves their hand across an object, a tiny bit is rubbed off. Over time, this contact can cause a lot of damage. For example, look inside this installation in the Smithsonian’s Natural History Museum:rubbed patina _NMNH
    See the part that looks shiny rather than dark? That’s where people have rubbed off the dark brown layer, or patina. It’s OK in this case—the museum intended for people to touch the object—but what if it weren’t?
  2. Everyone has oils on their hands. When you touch something, you leave some of those oils behind, creating your unique fingerprints. Those residues also can cause damage. Check out this lacquer lid of a ewer in our collection that has fingerprints etched into the surface from oils left behind. We can’t get the prints off; they are now part of the object.

    Fingerprint on the lacquer lid of a Karatsu ware ewer or freshwater jar.

    Fingerprint on the lacquer lid of a Karatsu ware ewer or freshwater jar.

  3. Unless you just washed your hands, remainders of anything else you touched recently will be left on the art as well. So those Nacho Cheese Doritos you had in your lunch? Yup. They’re on there too. As conservators, we wash our hands really well before working with art. And for really sensitive materials, like metals or lacquer or ivory, we also wear gloves.

Try This
Many works of art and historic objects are unique, the only examples of their kind in the world. And every time someone touches one of these objects in the gallery, we lose a little bit of history. Wanna see what I mean? Try this activity and see what happens—and send me pictures!

Take a piece of white printer paper and cover half of it with plastic wrap. Place it at the door of your house or classroom, or another place with a lot of foot traffic (the bathroom, maybe?). Ask everyone to touch or rub the material every time they walk by. Check back in two weeks. What has happened to the exposed part of the object? How does it compare to the side that is covered? What does it make you think about museums’ “don’t touch” policy?

collage

This is the first in a series of blog posts for kids who are interested in art conservation. Follow along for more behind-the-scenes looks at why and how we care for our collections, working to protect and conserve art for you today as well as for future visitors. What do you want to know? We’d love to hear your questions and comments!

Shining a Light on Jades at the Freer|Sackler

Chisel-shaped object; China, Song dynasty, 960–1279; jade (nephrite, actinolite/tremolite); Gift of Charles Lang Freer, F1917.28

Chisel-shaped object; China, Song dynasty, 960–1279; jade (nephrite, actinolite/tremolite); Gift of Charles Lang Freer, F1917.28

Jade was the material most highly prized by the ancient Chinese. Its polish, brilliance, subtle and translucent colors, and extreme toughness have long been associated with the quality of virtue and the concepts of the soul and immortality. The Freer|Sackler’s collections of jades include works of exceptional artistic quality, as well pieces of great cultural, historical, and sociological importance. Searching Open F|S, our fully digitized collection, is a superb way to become familiar with this unparalleled group of jade objects.

Next year, we will further expand access to our holdings with an online jade catalogue. As we prepare to make the evolving field of research on Chinese jades available to the public, we decided to test objects not previously examined for mineral composition to ensure our reports are complete and accurate. Jade is a chemically complex material, and studying its mineral composition is one way to understand more about the choices made by artisans in ancient China. The material properties can provide insights into jade sources, how jades were worked, and how they have changed since they were made.

Xiao Ma, MCI intern, uses a portable Vis/NIR in to analyze a Neolithic jade bi.

Xiao Ma, MCI intern, uses a portable Vis/NIR in to analyze a Neolithic jade bi.

Xiao Ma, a recent intern at the Smithsonian’s Museum Conservation Institute (MCI), and I spent a few days studying the jades using two noninvasive methods: portable Fourier Transform Infrared spectroscopy (FTIR) and Visible-Near Infrared spectroscopy (Vis-NIR). Both techniques deliver data directly from the surface of a jade in just a few minutes, and because no sample is required, there is no risk of damage to the object.

Example of a Vis-NIR spectrum of a Liangzhu jade bead (F1912.29a) composed of nephrite. The fingerprint bands for nephrite include 1394 nm, 2316 nm, and 2388 nm.

Example of a Vis-NIR spectrum of a Liangzhu jade bead (F1912.29a) composed of nephrite. The fingerprint bands for nephrite include 1394 nm, 2316 nm, and 2388 nm.

How do FTIR and Vis-NIR work? The light we typically see is within the visible portion (400–760 nm) of the electromagnetic radiation spectrum, or the part that human eyes can detect. The light we cannot see, above and below the visible portion, plays an important role in analyzing the composition of materials. For instance, the FTIR technique uses mid-infrared light (2500–25000 nm) to interact with the molecules that make up a jade object. As the infrared light is reflected back to a detector, FTIR measures how well the jade absorbs it at each wavelength, helping us create a molecular fingerprint.

Vis-NIR spectroscopy uses light in the visible region (400–760 nm) and overtones in the near-infrared region (760–2500 nm) to measure light that a material absorbs and scatters. Using this method, we placed jade objects near a light source; the light reflected from the object was collected by the Vis-NIR’s photodetector. The Vis-NIR spectrometer is particularly useful for analyzing mineral composition, as it is highly sensitive to electron transitions in both the visible and near-infrared regions.

We analyzed a total of 103 jades, including bi disks, cong tubes, pendants, ornaments, beads, and axes. Besides the most common jade material, nephrite (tremolite/actinolite), we also found other minerals, such as serpentine, quartz, and diopside. Our research methods and findings promise to serve as guidelines for museums to quickly and noninvasively analyze jade collections. Stay tuned to see more discoveries in the online catalogue when it is released next year.

Museum TLC: Sound Advice

Visitors take a tour of "Peacock Room REMIX" during Asia After Dark.

Visitors take a tour of “Peacock Room REMIX” during Asia After Dark: PEACOCKalypse.

A recent article in the Washington Post talked about the possible effects of loud music on artworks during large-scale museum events. We hear you and appreciate your concern. In fact, sound, light, temperature, and security are all factors that go into the planning and exhibiting of artworks. How does a museum care for its objects on exhibit while providing interesting, closeup experiences for visitors? Let’s ask the experts.

When I spoke to Beth Duley, head of collections management at the Freer|Sackler, she talked about the delicate balance between care and access. “Smithsonian museums are open 364 days a year, and we host millions of visitors,” she told me, adding, “Maintaining that balance is part of the day-to-day function of our job. In my 25 years at Freer|Sackler, no artwork has ever been damaged at an event.”

According to Jenifer Bosworth, exhibitions conservator, the process of caring for artworks begins long before objects are chosen for exhibition. “Our conservation department ensures that all objects chosen for display are in good condition and that an appropriate level of security for each object is reflected in the exhibition design. Specially made cases and vitrines, as well as custom-built mounts, are all fabricated with the objects’ safety in mind. We want people to get as close as possible, because that’s an amazing part of seeing great works of art in person.”

This preparation keeps artwork protected both during normal wear and tear (the constant vibration of passing trucks, the occasional wayward umbrella) and extraordinary circumstances (the 2013 earthquake that rocked DC). “After the earthquake, I ran into the Peacock Room, and all of the ceramics were still safely held in their specially made mounts,” said Duley.

For special events, such as the museums’ popular Asia After Dark after-hours parties, the entire staff works together. Conservators, curators, and security guards start early and work closely with event planners to map out traffic flow and the placement of speakers, lights, food and drink, and furniture. Conservators and members of the collections management team act as monitors during the event to ensure that all works of art remain safe and sound.

And speaking of sound, what about the issue of loud music in the galleries? Bosworth told me, “If anyone on my team feels that vibrations from a music performance could affect construction materials within the galleries and thus potentially the art, we address the issue immediately.” In fact, the effects of loud music on works of art have been studied in the conservation literature.

We strive to protect our objects on display while providing visitors a variety of ways to experience and learn about our collections. Our staff works together to find the best ways to balance security and access. This allows visitors to return to the Freer|Sackler often, knowing that their favorite works of art will still be here for their children and grandchildren, and the generations to come.

Beyond the Instagram Filter

Blue and Gold: The Rose Azalea; James McNeill Whistler (1834–1903); United States, ca. 1890–95; watercolor on brown paper; Gift of Charles Lang Freer, F1894.25. Left to right: visible light; reflected infrared (IR); ultraviolet-induced visible fluorescence (UV). The yellow-green fluorescence in the UV image indicates the presence of zinc oxide (zinc white).

Blue and Gold: The Rose Azalea; James McNeill Whistler (1834–1903); United States, ca. 1890–95; watercolor on brown paper; Gift of Charles Lang Freer, F1894.25. Left to right: visible light; reflected infrared (IR); ultraviolet-induced visible fluorescence (UV). The yellow-green fluorescence in the UV image indicates the presence of zinc oxide (zinc white).

Most of us are familiar with the transformational power of Instagram filters such as Amaro and Earlybird, and the magic they can work for our amateur iPhone photography. But what can we learn in an art historical context by making use of traditional camera filters? Multispectral imaging uses cameras that can “see” into the ultraviolet (UV) and infrared (IR) wavelengths along the electromagnetic spectrum, allowing us to photograph features of artworks that are not visible to the naked eye. At the Freer|Sackler, I used the conservation department’s Nikon D100 camera and Kodak Wratten gelatin filters to create UVIR photographs of the museum’s entire collection of watercolors by James McNeill Whistler. These photographs will be used as part of a larger project called Whistler and Watercolor, a collaborative, technical art history research project by an F|S conservator, curator, and conservation scientist.

While most of Whistler’s oeuvre has had the benefit of in-depth study, the watercolors have been waiting for their turn in the spotlight. Whistler created more than three hundred watercolors in his lifetime, most of which were executed in the 1880s, during the height of his fame. Museum founder Charles Lang Freer acquired fifty-two of them. Whistler and Watercolor will provide Whistler scholars and enthusiasts with a technical description of the artist’s working methods in watercolor. Were his materials and techniques similar or significantly different from the way he used other mediums? How do they compare to watercolors by other artists of the time period? Did he follow the methods taught in watercolor manuals and how-to books of the late nineteenth century or was he more innovative and experimental?

Reconstructed 19th-century watercolor palette. Left to right: visible light; reflected infrared (IR); ultraviolet-induced visible fluorescence (UV)

Reconstructed 19th-century watercolor palette. Left to right: visible light; reflected infrared (IR); ultraviolet-induced visible fluorescence (UV)

Multispectral imaging using traditional photographic filters can help us answer some of these questions. Look at the three images above for an example of a reconstructed nineteenth-century palette (like Whistler’s) photographed normally and then using two gelatin filters with different light sources. Certain pigments exhibit characteristic behaviors in reflected infrared (IR) and ultraviolet-induced visible fluorescence (UV) that allow us to identify them. Cobalt-containing pigments, such as cerulean blue or cobalt green, become transparent and disappear completely in reflected infrared (at approx. 850 nm). With ultraviolet-induced visible fluorescence, red madder lake typically emits a red fluorescent “glow” due to the presence of a compound called purpurin. By using photographic filters, as well as a variety of other techniques to back up these visual observations, it will be possible to reconstruct Whistler’s use of watercolor pigments in the late nineteenth century to aid future research and study.

London Bridge; James McNeill Whistler (1834–1903); United States, early 1880s; pencil and watercolor on paper; Gift of Charles Lang Freer, F1905.115. Top to bottom: visible light; reflected infrared (IR); ultraviolet-induced visible fluorescence (UV). Note the enhanced visualization of the graphite underdrawing in the IR image.

London Bridge; James McNeill Whistler (1834–1903); United States, early 1880s; pencil and watercolor on paper; Gift of Charles Lang Freer, F1905.115. Top to bottom: visible light; reflected infrared (IR); ultraviolet-induced visible fluorescence (UV). Note the enhanced visualization of the graphite underdrawing in the IR image.

Zooming In: Crystal Clear

Photomicrographs at 6x and 50x magnification of stained-glass windows from a painting in the Haft awrang (16th c.) exemplify the use of geometric patterns in manuscript painting. Photomicrographs of a penny have been taken at the same magnifications to emphasize the minute scale of the painted patterns.

Photomicrographs at 6x and 50x magnification of stained-glass windows from a painting in the Haft awrang (16th c.) exemplify the use of geometric patterns in manuscript painting. Photomicrographs of a penny have been taken at the same magnifications to emphasize the minute scale of the painted patterns.

This is the third and final post in Amanda Malkin’s series exploring geometric patterns in Islamic paintings, focusing on the possible use of optical devices by the manuscript illustrator. Previous posts discussed Geometric Patterns in Islamic Paintings and Tools of the Manuscript Illustrator.

The first true magnifying lens—an instrument with a handle created for the purpose of magnification—was developed in 1250 CE by Roger Bacon in England. However, a large group of archaeologists and scientists believes that ancient cultures were experimenting with rudimentary optical devices, made from rock crystal, many centuries before Bacon.

Rock crystals with plano-convex surfaces dating from 2500 BCE to 1500 BCE have been found in Egypt, Greece, and Mediterranean cities. Many of these rock crystals were of optical quality, according to the definition put forth by Dominic Ingemark in his article “A Rare Rock-Crystal Object from Pompeii.” That is, the rock crystal is acceptably transparent and homogeneous with at least one surface that is curved with minor surface irregularities. Additionally, the crystal must be able to form a reasonable image.

There is an interesting, ongoing debate regarding the function of these highly valuable rock crystals. Some theories suggest they were used as decoration on furniture, game pieces, or medical instruments. Ancient sources describe bi-convex lenses—basically, glass or rock-crystal balls—that were used to cauterize wounds or remove tissue. These sources do not mention the use of plano-convex lenses as optical devices, and this absence is convincing evidence, for some, that they were not used as such.

However, other scholars argue that the craftsmen who made the “lens-shaped objects,” as they are sometimes called, would have had to use an optical device themselves to do such precise work. The minute, archaic decoration on engraved gems, coins, cylinder seals, intricate jewelry, and of course, manuscript illustrations also suggest that lenses were present and used. The quality and precision of the microscopic ornamentation seem inconceivable without the use of magnifying lenses.

A controversial theory suggests that, instead of using lenses, men with myopia, or nearsightedness, were sought out and trained as craftsmen. Their distorted, magnified vision could have been exploited for creative purposes. The hypothesis, based on thoughtful and clearly investigated theories regarding genetics and a possibly high occurrence of myopia in early civilizations, remains an over-reaching argument. It seems unrealistic to believe that, even with extensive training, men with myopia could have become the majority of master engravers. Their optic handicap would have hindered their work as apprentices: Publications state that master engravers traditionally dealt with the raw stone and carried out the intricate work, while their assistants did the grinding and polishing.

The lack of written historical evidence confirming the function of these somewhat mysterious objects has made this research incredibly intriguing. Although the results are inconclusive, it is certain that as more plano-convex rock crystals are unearthed, more knowledge and information will follow.

Mats Matter

The Gopis Search for Krishna from a Bhagavata Purana; Punjab Hills, India, ca. 1780; opaque watercolor and gold on paper; Purchase, F1930.84

The Gopis Search for Krishna from a Bhagavata Purana; Punjab Hills, India, ca. 1780; opaque watercolor and gold on paper; Purchase, F1930.84

The Islamic and Indian paintings at the Freer|Sackler are breathing a huge sigh of relief now that the pressure is off! Over the last few months, the paper lab of the Department of Conservation and Scientific Research has rehoused more than one thousand individual folios into new window mats. The window mats relieve the paintings’ fragile surfaces from any pressure when stacked in storage boxes—critical for their long-term preservation. Plus, the paintings just look better that way.

Every painting had to be individually measured and the measurements entered into a spreadsheet. The data was sent in batches to an outside contractor. In return, every couple of weeks we would receive 200–250 newly cut mats. We then had to remove the paintings from their old folders, add new hinges, and attach them into the new mats. We make our hinges in-house from Japanese paper, and each hinge is cut to size to fit the particular folio. Since at least two hinges are used to hold each painting in the window mat, we went through more than 2,024 individual hinges! Although one thousand new mats were cut, 1,012 individual folios were rehoused, since some are presented in double window mats (a single mat with two window openings).

Old, insubstantial folders at left, and new, clean and sturdy mats on the right.

Old, fragile mats on the left; new, clean, and sturdy mats on the right.

One hundred sixty-eight folios had already been placed in mats in-house for various rotations, exhibitions, and loans, bringing the grand total of matted folios to 1,180. But that’s not everything. We still have approximately one hundred Islamic and Indian paintings left to move into mats in the future. Then, on to other collections!

The project was funded by a Smithsonian Collections Care and Preservation Fund grant. It could not have happened without the untiring work of Amanda Malkin (Hagop Kevorkian Fellow in Islamic painting conservation and hinger extraordinaire), Stacy Bowe (mat-measuring maniac and intern), and Emily Cummins (pre-program intern).

Zooming In: Tools of the Manuscript Illustrator (part two)

Geometric patterns in Islamic manuscripts

Geometric patterns in Islamic manuscripts

Amanda Malkin is the Hagop Kevorkian Fund Fellow Paper Conservator at the Freer|Sackler. This is the second in a series of blog posts that explores geometric patterns in Islamic paintings.

It is clear that the complicated geometric patterns I have observed in many manuscript paintings have, at their core, the circle and the square. During my research into the tools and techniques of manuscript painters, I uncovered two schools of thought regarding the working processes and specific methods used to create these miniscule, complex patterns.

The first theory—and my initial assumption—is that Islamic artisans and craftsmen utilized the long-appreciated ruler and compass to create geometric patterns, which are known as girih. It is exciting to see that, by overlapping certain shapes and connecting those shapes with the straight line of a ruler, one can produce endless geometric constructions. This theory, known as strapwork, is accepted by many scholars and institutions that collect and study Islamic art.

It is possible, however, that another method of construction was utilized in ancient Islam, and this is the second, more recent hypothesis. Physicists Peter J. Lu and Paul J. Steinhardt, of Harvard and Princeton Universities, respectively, proposed that, by using a group of five tiles of varying shapes, artisans could more quickly and exactly construct extremely complex geometric designs. These tiles are called Girih tiles, and they are described by the physicists as “equilateral polygons decorated with lines.” The shapes of the polygons are not random but stem from the empty spaces observed within the basic patterns of circles and squares. When you observe, for example, repeated hexagons, you will see that there are additional shapes created between them.

Steinhardt and Lu’s theory is based on the existence of a late fifteenth-century object in the collection of the Topkapi Palace Museum in Istanbul, Turkey, known as the Topkapi Scroll. The scroll was discovered in 1986 and contains drawings and pattern constructions using the five Girih tiles, likely used as a reference document in a craftsman’s workshop during the Timurid dynasty.

In light of the exciting evidence discovered on the Topkapi Scroll, I believe that both methods described above were likely utilized by illustrators in different regions and with varying skill levels, in order to assist them in the manner that best suited their work.

View Peter Lu’s animation of the Topkapi Scroll.

Stayed tuned for Amanda’s third—and final—post in the series.

Larger Than Life: Restoring the Empress Dowager

The painting of the Empress Dowager, before, during, and after conservation.

The painting of the Empress Dowager, before, during, and after conservation.

David Hogge is head of Archives at the Freer|Sackler.

In 2011, the Sackler acquired a life-size portrait of China’s Empress Dowager Cixi (1835–1908) painted by Katharine Augusta Carl in 1904. That year, the painting was one of the Chinese government’s entries at the St. Louis Exposition. Then, it was given to President Roosevelt, who had it added to the Smithsonian’s collections. The painting was shown in the Smithsonian’s Art and Industries Building before being loaned to a museum in Taiwan in the 1960s, where it remained for more than forty years.

Though it was halfway around the world, the painting presented a perfect companion to the original Empress Dowager photographs in the Freer|Sackler Archives that were featured in the exhibition Power|Play: China’s Empress Dowager. I suggested that we should have the painting returned to the Smithsonian and continue to tell the tale of international diplomacy through portraiture. Bringing it back was a big risk: we learned that it was badly deteriorated, and the elaborately carved, half-ton frame was in equally poor shape. Nevertheless, the painting was shipped to Washington, DC, and sent to our storage facility in Suitland, Maryland. When we unwrapped the painting, our worst fears were realized: the canvas was in dreadful condition with tears, cracks, peeling, and layers of grime and discolored varnish.

The Empress Dowager, larger than life.

The restored painting of the Empress Dowager, with MCI conservators Jia-sun Tsang and Inês Madruga.

Since hiring an outside conservator would have been prohibitively expensive, at the time I assumed that we would have to box up the painting and put it away for good. Fortunately, Suitland is also the location of the Smithsonian’s Museum Conservation Institute (MCI). Senior Painting Conservator Jia-sun Tsang was brought in to evaluate the painting. Rather than walk away in despair, she immediately saw the painting’s potential as well as its historical importance. Miraculously, Jia-sun requested and was granted the time and resources necessary to rescue the painting. While she and conservation fellow Inês Madruga oversaw a raft of analyses and treatments, Senior Furniture Conservator Donald Williams managed the repair of the frame. Overall, some twenty-three conservators, interns, art handlers, technicians, and contractors quietly labored away to restore the empress’s portrait. Last month, the painting and its frame were united once more. Thanks to these heroic efforts, in time, we hope to share this historic artifact with the public.

View a slideshow of the conservation process. Learn more about this and other images of the Empress Dowager and their role in rehabilitating her international reputation.

Remembering Collector Robert H. Ellsworth

Nandi; India, Chola dynasty, 12th century; bronze; Purchase, F1985.30

Nandi; India, Chola dynasty, 12th century; bronze; Purchase, F1985.30

Former head of the Department of Conservation and Scientific Research at Freer|Sackler, Paul Jett was with the museums for nearly thirty years.

Robert Hatfield Ellsworth, a preeminent collector and dealer of Asian art, passed away on August 3 at the age of eighty-five. Long a friend and benefactor of the Freer|Sackler, Mr. Ellsworth gave his collection of Chinese calligraphy to the museums and also supported many of their fundraising efforts. In addition, he was the source for a number of important works purchased by the museums, such as the beautiful bronze figure of Nandi pictured above. Mr. Ellsworth said he found this work being used as decoration near a swimming pool at the home of the owners of the Tandy Leather Company in Texas. (In the Freer|Sackler, the piece earned the nickname “The Tandy Nandi.”)

When I met Mr. Ellsworth, I was a young conservator studying a particular type of Chinese Buddhist bronze from Yunnan, one example of which was in his collection. I was certainly not known in the field of Asian art, and yet Mr. Ellsworth treated me with a gracious, generous cordiality that overwhelmed me. He allowed me to visit his home and study the bronze, and then went on to show me dozens of other bronzes from his collection. It was breathtaking and the first of many visits I made to see his collection and talk about art. A raconteur of the first order, Mr. Ellsworth always had a story to tell, about his collection, his life, or the people he knew. He could be incredibly charming, funny, and welcoming.

For years after my first visit, whenever Mr. Ellsworth saw an article or news about Yunnanese Buddhist bronzes, he would send me copies of the information. I was stunned once to learn that Mr. Ellsworth had bought one of these bronzes for about five times more than anyone had previously paid, but it took him just a month or two to sell it for a significant profit. Mr. Ellsworth not only knew the art market well, but he also seemed able to forecast it. Knowing the art market is one thing; knowing art is something else. I have always believed that, in his prime, Mr. Ellsworth had an eye for art that was better than that of anyone else in the field I ever met.

The museums have lost a good friend, and there are many more who will mourn and miss Robert Ellsworth.

X-Ray Visions

Fused mosaic plaque; Ptolemaic dynasty to Roman period; 100 BCE–100 CE; Egypt; F1909.506

Fused mosaic plaque; Ptolemaic dynasty to Roman period; 100 BCE–100 CE; Egypt; F1909.506

Ellen M. Nigro is an intern in the Department of Conservation and Scientific Research at Freer|Sackler.

In 1909, Charles Lang Freer made his third trip to Egypt and bought a collection of nearly 1,400 ancient glass beads, vessels, and mosaic fragments in Cairo. The objects are mainly XVIII dynasty, Ptolemaic, and Roman period Egyptian pieces, but include some later Islamic fragments. Although the collection varies a bit in geographic origin and time period, all the pieces are colorful examples of fine craftsmanship, from intricate millefiori inlays to cast amulets. Freer shipped the collection straight to the Smithsonian in 1910; since then, some of it has been exhibited, but the vast majority was left unstudied. However, the current installation The Nile and Ancient Egypt features selected glass vessels from this collection. Concurrently, a scientific study of the glass collection using x-ray fluorescence (XRF) is helping researchers at Freer|Sackler understand better the elemental composition of the objects.

This image was taken with the XRF spectrometer camera of the glass object at top. The instrument allows us to focus the x-ray beam using a laser and video camera.

This image was taken with the XRF spectrometer camera of the glass object at top.

XRF is a non-destructive, scientific, analytical method that is capable of detecting inorganic elements with certain atomic weights. The colorants in glass are mainly transition metals (those found in the middle of the periodic table such as manganese, iron, cobalt, and copper); therefore, XRF is a good way to learn about what materials the ancient glassmakers used to make the vibrant colors in this collection. (It is not able to determine chemical structures or detect organic compounds, chemicals mainly composed of carbon, hydrogen, and oxygen.) XRF uses an x-ray beam generated inside the instrument to displace inner shell electrons in the elements of the analyzed material. Higher energy electrons then cascade down to lower energy levels and release energy in the form of fluorescence. As this fluorescence is released, the instrument detects the signals and creates a line graph on a computer program, where the analyst can see the results. The x-axis represents the energy of each signal in kiloelectronvolts (keV), while the y-axis represents the intensity in number of pulses. Since each element produces a characteristic set of peaks at specific energies, the scientists can determine what elements are present in the material.

The graph gathered from the blue area in the fused mosaic. The cobalt peak is highlighted because it is likely the main colorant.

The graph gathered from the blue area in the fused mosaic. The cobalt peak is highlighted because
it is likely the main colorant.

Knowing the colorant can also provide clues about the time and culture in which a piece originated. For example, if a white glass produces strong antimony and calcium peaks, it could be colored with calcium antimonate, a common white colorant in XVIII dynasty Egypt. But if a white glass sample produces prominent tin peaks, the results suggest the colorant could be tin oxide, a material used starting around the fifth century CE. At the end of this XRF survey, the scientists at Freer|Sackler will have a much better understanding of the elemental composition of these glass objects. Although the results from XRF alone only give a small glimpse into the history of these objects, this study can help guide further scientific and art historical research.

Learn more about Conservation and Scientific Research at Freer|Sackler and check out another blog post on x-ray art.