When is cleaning coins not like cleaning coins?

Alexis North, Williams Project Conservator

 

This sounds like a joke that only archaeological conservators would enjoy, but it’s actually an honest question! The answer is (in this case at least), when those coins are reused in other objects.

Before treatment photo of 42-35-370.

This necklace comes from Coban, Guatemala. It is made from black glass roundelle beads, interspersed with 144 coins from Guatemala, Mexico, and Spain. It was collected in the early 20th century, but the coins all date to before 1900.

photos of the obverse and reverse of a Guatemalan 50 cent coin, 1870; a Mexican 2 Reales coin (date illegible); and a Spanish 2 Reales coin, 1835.

There are also a number of other beads and charms, including two crosses, two round silver beads, and a black faceted stone charm in a silver bezel. The necklace is in good condition, and the only treatment it needs is a nice overall cleaning.

This necklace is being prepared for display in our new Mexico and Central America gallery, along with this necklace, also made from coins:

Before treatment photo of 42-35-41.

The pendant on this necklace is made from a large 1 Sol coin, dated 1892, surrounded by 8 small 1/4 Real coins, all from Guatemala. On top of the 1 Sol are two small deer, and suspended below are 2 quetzal birds, and a cross.

Coins are important in Guatemalan culture. These necklaces would have been symbols of wealth, and be passed down from mother to daughter within a family. Even today, when a couple decides to get married, the groom will often give the bride a gift of 13 coins in a small box, called an arras.

Come see these pieces when they go on display in our new gallery!

Ancient faces in the Middle East Galleries

Our new Middle East Galleries open next week and they will feature over 1200 artifacts from our collection, including many iconic objects like the Ram in the Thicket, the Bull-headed lyre, and Queen Puabi’s headdress. Oh, and for those of you who are always asking about our cuneiform tablets, do we have a treat in store for you – there are dozens and dozens in the galleries. The majority of the objects in the exhibition were excavated by Penn archaeologists, many nearly a century ago.

ALL of these objects came through our Conservation Labs to prepare them for the galleries and many needed significant treatment in order to ensure their stability for long-term display. Our Middle East Galleries (MEG) team has worked diligently and tirelessly on this project – you can read more about some aspects of this work on the Penn Museum blog here.

The triumphant column team poses next to the 4 recently conserved mosaic column drums from Tell al-‘Ubaid, Iraq. This project took months to complete.

In just over a week, visitors to the Museum will have the opportunity to get up close and personal with these newly-conserved objects. Everyone will be drawn to the highlight pieces mentioned above and here, but the other pieces are worth lingering over too. It’s usually impossible to see them as closely as we do during the conservation treatment process, so I thought I’d give you the opportunity to see 2 small but beautiful objects closer than you can in the galleries.

B8997 (left) and B9026 (right)

These 2 female figures, both excavated from Nippur, Iraq, will be on display in the same case in the Middle East Galleries. They’re small, just several inches long. The figure on the left was likely a doll which would have had articulated arms; you can see the holes where they were once attached. Fortunately, both artifacts required very little treatment. B8997, the figure on the left, does have a large, but stable crack that did not require any treatment. Examination under the binocular microscope revealed small amounts of burial dirt on both figures which had escaped previous cleaning campaigns, so both were carefully surface cleaned to remove this soil.

Detail of B9026 before (left) and after (right) cleaning, 7.5X magnification

As I worked on these figures, I captured some images with the camera attachment on our Leica microscope. Both objects are made of bone and are delicately carved. The reverse side of the doll’s head has an unworked area that nicely shows the cancellous (or spongy) bone features.

B8997 detail of front (left) and reverse (right), 7.5X magnification

Their time in the lab was brief – they only stayed for a day or 2. But in the midst of the hustle and bustle of preparing for these galleries, it’s nice to take a moment to appreciate the details.

The Middle East Galleries open to the public on Saturday, April 21. Our department has a few loose ends to wrap up with that project (and a few loose ends on the blog – stay tuned for a last blogpost on the mosaic column treatment) but we’re already turning to our next big tasks – the renovation of our Mexico & Central America Galleries, Africa Galleries, and Egyptian Galleries.

Many new faces in the lab…

by Williams Project Conservator Alexis North

Yesterday, I was able to make several new friends, when the American section brought these objects up to the lab, in preparation for the reinstallation of our Mexico and Central America gallery:

 These are a group of Zapotec ceramic effigy vessels from Mexico. These types of vessels are usually found in tombs, and their meaning depends on where and how they were buried. They are often found in groups, and with other associated burial materials.

Each of these effigy vessels is elaborately and uniquely decorated. Some have human faces, some are wearing masks, and some even have animal features.

These two vessels (NA6361; 29-41-707) depict humans wearing masks.

Most of these vessels are in good condition, intact or with only small losses. At least two, however, will need a little more conservation to get them ready to display. This vessel was originally covered with a white stucco coating:

Vessel 29-41-702, depicting a masked seated figure.

The stucco is now starting to lift from the surface, and any handling can cause small pieces of the stucco to fall off. It will need to be carefully stabilized before the vessel can go on display.

Detail of the headdress of 29-41-702. The red arrows show areas where the stucco is lifting off the surface of the ceramic.

And this vessel shown below has some loose fragments which will need to be rejoined. Thankfully the amazing duck bill on his face is still intact!

Before treatment photo of 31-26-1.

For (a lot) more information and other examples of these types of vessels, check out the Foundation for the Advancement of Mesoamerican Studies, Inc., and their database on Zapotec effigy vessels.

A Columnar Matter Part I: The Technical Examination of a 3rd Century BCE Mosaic Column from Al Ubaid

Marci Jefcoat Burton

My first project as a curriculum intern with the Penn Museum Conservation Department involves the conservation of a mosaic column from the Ninhursanga temple site of the ancient Mesopotamian city of Tell al-Ubaid in Iraq (column in digital collections: (B15887.1 – 15887.4). Dated as 2400 – 2250 century BCE, the column was excavated sometime between 1919 – 1924 as a pattern of alternating triangular and diamond shaped shell, pink limestone and shale tiles. Fortunately, the years of resting in the compacted dirt of the burial environment preserved the shell and stone tesserae and maintained their original conformation. The original column interior, more than likely palm logs, did not survive the centuries of burial.

Figure 1 (left): Before treatment image of the four column sections stacked together to make a mosaic column.
Figure 2 (right): Reconstructed façade of the Ninhursanga temple of Tell al Ubaid. The columns were originally believed to be outside the entrance of the temple doorway, although it is not certain if both columns were on the exterior or interior of the building. (Both images courtesy of The Metropolitan Museum of Art. (2003). Art of the First Cities: The Third Millennium B.C. from the Mediterranean to the Indus. The Metropolitan Museum of Art: New York)

Without a support, the delicate tesserae were lacking a method of storage and display. Working with the materials available on site and with technology available in the early 20th century, the archaeological team constructed four drums to mount the tesserae into four stackable sections. Although reports attribute the original 3rd century BCE binding medium as bitumen (i.e., asphaltum, tar, pitch) to hold the tesserae in place on the original wooden supports, the 20th century excavation team reconstructed the shell and stone mosaic pieces with a grey plaster. In addition, only half of each drum holds original tesserae, and the remainder of each section is filled with a painted plaster reconstruction.

Figure 3: c. 1920s, on-site with the recently assembled tesserae onto the wire mesh and wood drums. (Image courtesy of http://www.mesopotamia.co.uk/tombs/story/page07b2.html).

X-radiography of one of the drum sections revealed that each drum is constructed as a hollow metal mesh cylinder with wooden caps on each end, and several nails to keep the cylinder together. After 100 years in this conformation, the drums have become problematic for the long-term display of the tesserae. Fluxuations in temperature and humidity, as well as the weight of the tiles and the thick, rigid plaster have caused opposing shifts in the internal structure, leading to the formation of cracks in the plaster and several tiles to dislocate and fall from the support.


Figure 4: X-radiographs of column section B15887.3 detailing the inner drum structure consisting of an open wire mesh and hollow interior. (Left (a)): X-radiograph of the column section side reveals the radiopaque grid pattern indicative of a metal mesh. (Right (b)): X-radiograph of the column section top, revealing numerous nails in various locations that hold the cylindrical drum together. (X-radiographs courtesy of Julia Commander (2016)).

The column, with all four sections, is one of the many objects selected for exhibition in the upcoming Middle Eastern Gallery (scheduled to open in Spring 2018). Therefore, it was decided it was time for the over 4,000 year old tesserae to be removed from the hollow wire mesh supports and then remounted onto a structured, solid support made with materials that will prevent structural damage and be sustainable for its preservation and long-term display in the gallery. Following a treatment protocol implemented successfully on one of the four column sections by Julia Commander (WUDPAC, Class of 2017), I will deconstruct the tesserae from the current supports, clean and repair each piece, and remount the tesserae in their same arrangement to new cylindrical supports made from solid, very dense Ethafoam measured to the exact shape for each section awaiting treatment. Stop by the Artifact Lab to see the progress of the column treatment, which is already underway, or stay tuned for a follow up blog post!

Figure 5: Start of the disassembly of the shell, pink limestone and shale mosaic tesserae from column section 2. Note the color difference of the large painted plaster fill on the left versus the original tesserae on the right. Several breaks are also observed in the inlays (most notably the beige shell pieces) and a layer of dark, brown grime has accumulated on the surface overall.

Update on one of the Al-Ubaid Friezes

The treatment of the two Al’Ubaid Friezes has progressed since the last post. This post is going to focus on what we have been doing with the marching bull frieze (B15880). This frieze is made up of shell pieces for the bulls (probably made from large conch shells) on a background of black stone pieces with copper alloy borders at the top and bottom of the frieze.

B15880, frieze of 6 bulls

The archaeologists who excavated these materials in the 1920’s set the mosaic into plaster over a wooden backing. Overtime, this support had started to flex, causing the plaster to separate from the wood. This lead to movement of the mosaic frieze casing pieces to loosen and detach as well as causing breaks in the stone. Over the years detached pieces were re-adhered using a variety of different adhesives depending on when the work was done.

Diagram of B15880 showing the 1920’s backing materials in relation to the copper, shell, and stone materials of the frieze.

Because of these issues the mosaic has now been removed from the 1920’s support. One of the perks of having the pieces free from the support, is that we can see both sides of each piece. While we knew from the X-ray that in antiquity they had been attached to the original support using copper alloy wire twists, we can know see those twists.

Detail of the shell showing the remnants of a copper alloy twist/fastener

Detail of the stone showing the remnants of a copper alloy twist/fastener

Now we are working to stabilize each individual piece. The shell bulls are in very good shape, so that has just been cleaning to remove the plaster, areas of over-paint, and adhesive residue. The stone pieces are, however, in much worse shape. We have been consolidating them to restore the cohesion of the stone, joining broken fragments, and cleaning to reduce plaster and old adhesives.

Image showing the progress on cleaning and stabilizing the mosaic pieces.

The next step will be to adhere the clean and stable pieces to a new backing with new grouting around them to keep them in place. Exactly what materials we will use and how that will be done is something we are still working on, but here you can see some of the test tiles that we are making to help make that decision!

Test tiles with bone beads and different possible grouting materials.

 

Moose hair and birch bark

Moose hair and birch bark. Those are 2 materials that we have not written about on this blog before. But now that we are working in the Artifact Lab on objects for all of our upcoming exhibitions and loans, we are seeing a wider variety of artifacts and materials in the lab.

This embroidered birch bark case will be installed in our Native American Voices gallery later this month, so it is in the lab for examination and treatment.

Views of both sides of a small birch bark and moose hair case (45-15-1328) 

The 2-part case (the lid is a separate piece) was purchased by the museum in 1945. It is attributed to being Huron and from Canada.

The case itself is made of birch bark and it is embroidered with moose hair. The intricate details are difficult to appreciate without being able to see them up close. So, let’s take a closer look at the decoration:

Details of the moose hair embroidery, 7.5X magnification

Details of the moose hair embroidery, 20X

The case and lid are edged with bundles of moose hair attached with thread:

Details of the moose hair embroidery, 7.5X magnification

As you can see in the image above, some of the threads attaching the moose hair bundles along the edges are missing, causing hairs to become lost. These areas, as well as splits in the birch bark, will have to be stabilized before this case can go on display.

Check back for post-treatment photos, and visit the museum to see this case on exhibit by the end of May.

Two Al-‘Ubaid friezes

There will be a heavy rotation of objects from Iraq and Iran in the Artifact Lab as we work on objects that will be installed in our new Middle Eastern Galleries, scheduled to open in April 2018. Two of the newest pieces to come into the lab (but 2 of the oldest things in here) are these friezes from Tell Al-‘Ubaid, a site located west of Ur in Iraq, which date to the Ubaid period (ca. 6500-3800 BCE).

B15880, frieze of 6 bulls.

B15883, frieze of 3 ducks

These frieze fragments were excavated by Charles Leonard Woolley in 1924 as part of the British Museum/University Museum Expedition to Al-‘Ubaid. They both have been heavily reconstructed, displayed a lot, and loaned several times, so this is not their first time in the conservation lab. Due to some condition issues and because we are preparing them to go on long-term exhibition here at the museum, we have decided to deconstruct the old repairs and reassemble the friezes using materials that we expect will last longer and provide greater protection for the original pieces.

Conservation treatment of the frieze with the bulls began a week ago:

The bull frieze after 2 days of treatment.

One week later, even more progress has been made:

The bull frieze after 1 week of treatment.

Detail of the first bull freed from the frieze, 7.5X magnification. The bulls are made of shell and are in excellent condition.

Prior to treatment, the friezes were x-rayed to provide a better understanding of their construction and previous repairs, and to guide conservation treatment.

A digital x-ray radiograph of a portion of the bull frieze showing ancient methods of attachment (some are circled in red), modern nails (circled in blue), and a large fill made as part of a previous conservation treatment (circled in green).

Check back for updates on this exciting and complex treatment.

 

Cleaning Questions and Cross-Sections

Julia Commander is a third-year graduate student in the Winterthur/University of Delaware Program in Art Conservation. She is currently completing a curriculum internship at the Penn Museum.

The investigation of the painted Ptah-Sokar-Osiris figure continues. Previously, I mentioned that I would be taking cross-section samples to gain a better understanding of the paint layers. This type of sampling involves taking tiny (less than 1 mm) flakes of paint to capture the stratigraphy. Once I have a slice showing all of the layers, I can look at the edge under magnification to observe the structure from surface down to ground level.

In this case, I took four samples from representative areas on the figure in order to compare the layers. Before sampling, I looked at each area under magnification and made notes about surface characteristics and conditions. To sample, I continued working under magnification with a fresh scalpel blade.

L-55-29, cross-section sample areas. You can also see the darkened appearance of the front surface.

As you can probably imagine, handling a tiny little paint flake can be tricky. To make observation possible, conservators embed cross-section samples within a mounting material, typically a clear resin. Mini ice cube trays are perfect for making small blocks of resin for this purpose. After embedding the sample between two resin pours, one face of the cube is polished to a glossy finish. The polishing process helps to get a clean cut of the sample from an edge-on perspective.

Mounting cross-sections with a clear polyester resin, molded in a mini ice cube tray. The cubes are then polished with Micro-Mesh cushioned abrasive cloths.

You never know exactly what your cross-section will end up looking like until it’s under the microscope. Flakes can shift while the resin cures or be affected by polishing, so it’s an exciting moment to see the results. Sample X2, below, shows a clear view of the layer structure. Similar to the way conservators use ultraviolet (UV) light during object examinations, cross-sections are often viewed with various light sources to show different properties. Here, you can see the sample in visible light and UV light (365 nm).

Sample X2, 100X total magnification, in visible light (right) and ultraviolet light (left). Samples were viewed on a Zeiss Axio Scope.A1 polarized light microscope.

We can see a few interesting features here. The sample area appeared to have predominantly red paint, although it was heavily obscured by the surface darkening. The uppermost layer of dark material could be related to a discrete layer of soiling or coating, or we could be seeing black paint. Since the front surface of the figure is intricately painted, it’s difficult to completely rule out paint as a possibility. Aged coating materials often fluoresce in UV light, which can help to distinguish them from underlying paint layers. In this case, we can see small flecks of fluorescence (indicated by the red arrows) but not a distinct fluorescent layer. We can also observe faint fluorescence in the ground layer, which is consistent with the idea of an aged animal glue binder.

Another sample, X4, came from an area of plain red paint without any adjacent black designs. This area was also affected by the surface darkening issue, although to a less severe extent. Here, instead of a discrete layer of dark material, we can see small specks above the red paint layer (indicated by the red arrows). These dark specks are most likely related to soiling or discolored coating and unlikely to be original applied paint.

Sample X4, 200X total magnification, visible light (right) and ultraviolet light (left). Samples were viewed on a Zeiss Axio Scope.A1 polarized light microscope.

The cross-section samples offered some insights into the multi-layered nature of the delicately painted surface. As with most analytical techniques, results lead to more questions than clear-cut answers. Luckily, my colleagues here in the lab got together to talk about this complex condition issue and offer different perspectives and approaches. To clean or not to clean the darkened layer? Clarifying the surface details would be helpful for interpretation, but an even more gentle cleaning system will be needed to avoid damage to paint layers. The consensus: further testing needed!

Considering Cleaning

Julia Commander is a third-year graduate student in the Winterthur/University of Delaware Program in Art Conservation. She is currently completing a curriculum internship at the Penn Museum.

It’s time to check back in with the Ptah-Sokar-Osiris figure. In my last post, I mentioned a few of the condition concerns including a significant darkening over the front surface. The uneven surface poses interesting challenges for cleaning, and there are multiple approaches and methods to consider.

Before cleaning proceeds, it is important to understand both the nature of the surface discoloration and the properties of the paint layers. Egyptian objects are not always straightforward, and Ptah-Sokar-Osiris figures have a broad range of condition issues and treatment histories. Check out the British Museum’s online collection for a fascinating look at comparable figures. Discolored or yellowed varnishes have been observed on Egyptian painted surfaces, such as the shabti box described in a previous post. One way to assess surface discolorations is ultraviolet (UV) light illumination, a non-destructive lighting technique. In the UV portion of the energy spectrum, aged coating materials including varnishes and adhesives often fluoresce brightly. Areas that absorb more UV light appear darker in comparison. For this figure, areas of fluorescence do not appear to correspond to the pattern of discoloration, which is most noticeable on the platform under the feet.

L-55-29. In normal light (left), you can see the darkened surface of the front of the figure. In ultraviolet (UV) illumination (right), specific areas fluoresce. The pattern of UV fluorescence does not correspond to the discolored areas or suggest an overall coating.

Additionally, the surface darkening extends over large areas of damage and paint loss, suggesting that it occurred later in the object’s history. In an attempt to understand the darkened surfaces, I will take cross-section samples, which involve tiny (less than 1 mm) flakes of the paint layers. By looking at the edge of a paint flake under magnification, I can observe the stratigraphy from surface down to ground level. One way to visualize this technique is to think about slicing a cake to see the layers inside. To make handling tiny paint flakes easier, they can be mounted in resin for observation under magnification. Through normal light and UV light microscopy, the presence of discrete coating or soiling layers may be observed.

To characterize the behavior of the paint layers, solubility tests were conducted under magnification with small amounts of solvent on cotton swabs. For this painted figure, surfaces appeared to be water sensitive but relatively stable in other solvents. This finding is consistent with typical Egyptian paint binders such as gums or animal glues, which are both water sensitive. Once I know what affects the original surface, I will be able to think about designing a strategy to reduce darkening while avoiding disruption of the paint layers.

Dry surface cleaning is one of the first methods to test for a water sensitive surface. Cosmetic sponges and soot sponges lifted significant dirt and grime, although the appearance of the figure’s surface was not visibly improved. Water-based solutions and small amounts of solvent were tested in discrete locations to assess their efficacy. Water-based, or aqueous, cleaning solutions can be adjusted with buffers and chelators to more effectively lift dirt and break up staining. Chelators, such as citrate and EDTA (ethylenediaminetetraacetic acid) are complex ions that attach to metal ions, a key component of most types of dirt. A citrate solution at pH 8 was found to be very effective for lifting dirt and staining, but I wanted to minimize surface interaction with water. One method to manipulate these interactions is to work through silicone materials. Silicone gels, such as Velvesil Plus, can from stable emulsions that hold aqueous solutions. Silicone solvents, such as cyclomethicone D4, can saturate surfaces and act as a barrier layer to protect from water.

Testing dry surface cleaning with a cosmetic sponge on the figure’s base.

Testing aqueous cleaning solutions to reduce discoloration with a small cotton swab.

Could this be used as an overall cleaning solution? A larger test area suggested that the combination of materials, when applied carefully with brushes and worked over the surface, lifts dirt without visibly disturbing paint layers. However, the cleaning effect is slightly uneven, which raises concerns about whether this technique will significantly improve visibility and legibility of surfaces. Since this object is a long-term loan from the Philadelphia Museum of Art, continuing discussion with the PMA senior objects conservator, as well as Penn Museum curators, will help clarify these decisions.

In addition to aqueous cleaning methods, I researched the feasibility of laser cleaning. Conservators have successfully employed laser cleaning in many scenarios where discrete layers of soiling need to be removed from surfaces. For Egyptian artifacts, some of the primary challenges include fine control over complex surfaces and slight yellowing after cleaning. While the literature suggests that laser cleaning is unlikely to be the right solution in this scenario, we decided to experiment with a mock-up test panel to gain a sense of the technique’s future applications in the lab. This involved gathering typical Egyptian pigments, including the famous Egyptian blue and green, and mixing appropriate binders to mimic historic surfaces. The panel consists of an animal glue ground with gum arabic paint, coated with an additional layer of mastic varnish for half of the test areas. Mastic, a plant-based resin, is comparable to traditional Egyptian resins such as pistacia. After adding a little bit of “dirt,” a sticky mix of starch powder and pigments, I am ready to start exploring the efficacy of our laser cleaning system for painted surfaces.

Creating a mock-up panel to test laser cleaning on painted surfaces. Materials include Egyptian pigments mixed with gum arabic binder, an animal glue ground, and mastic varnish.

Selected resources:

Korenberg, C., M. Smirniou, K. Birkholzer. 2008. Investigating the use of the Nd:YAG laser to clean ancient Egyptian polychrome artifacts. Lasers in the Conservation of Artworks: 221-226. London: Taylor and Francis Group.

Larochette, Y. 2012. Wolber’s world: A review of a textile wet-cleaning workshop held in Oaxaca, Mexico. Western Association for Art Conservation (WAAC) Newsletter 34(1): 24-26.

Roundhill, L. S. 2004. Conservation treatment considerations for an Egyptian polychrome wood coffin. Objects Specialty Group Postprints 11: 89-102.

Ptah-Sokar-Osiris and Treating Painted Surfaces

Julia Commander is a third-year graduate student in the Winterthur/University of Delaware Program in Art Conservation. She is currently completing a curriculum internship at the Penn Museum.

As a conservation intern working in the Artifact Lab, I was able to go shopping through shelves of Egyptian objects and scope out interesting treatment projects. A painted wood statue, depicting the composite god Ptah-Sokar-Osiris, immediately caught my eye. The figure has intricate painted designs decorating the mummiform figure and its base, as well as gilded details in the face and headdress.

Ptah Sokar Osiris Statue, L-55-29A-C

L-55-29C, detail of paint and gilding

High-status burials in 19th dynasty Egypt often included this type of mummiform statue. Comparable examples of the popular object type exist in collections worldwide, such as the British Museum and the Metropolitan Museum of Art. Common characteristics include carved wood, a preparatory gesso layer, polychrome design, and in some cases, a coating of varnish. Ptah-Sokar-Osiris statues also frequently feature small compartments carved into the wood figure or base. These cavities could contain small papyrus scrolls or textile wrappings. While examining the object with this in mind, I noticed a faint rectangular shape on the reverse of the figure’s head.

X-radiography, a non-destructive imaging technique that helps clarify construction details, was perfectly suited for the question of the compartment. Without disturbing the delicate painted surface, we were able to observe that a rectangular cavity is in fact cut into the head of the figure. Although the cavity appears to be empty, this interesting construction detail is consistent with similar Ptah-Sokar-Osiris figures.

L-55-29A detail (left) and X-radiograph (right). Image captured from 55 kV, 2 mA, and 6 second exposure.

The statue has several condition issues, such as actively flaking paint and significant darkening over the front surface. Additionally, the figure is unable to stand upright in the base, and the components do not fit together securely. Upcoming treatment aims to address these issues, and I will be searching for the right approach to cleaning and consolidation. The complex surface made of wood, gesso, and paint will require detailed testing to find appropriate solutions.

To further investigate painted surfaces and possible coatings, I used multispectral imaging (MSI), which incorporates multiple light sources to reveal details that cannot be seen in visible light. Interesting findings included the presence of Egyptian blue in the figure’s wig and broad collar, as well as the headdress. This pigment shows up in visible-induced infrared luminescence and is easily distinguishable from surrounding pigments.

Detail of multispectral imaging, highlighting Egyptian blue pigment. Normal light (top), visible-induced infrared luminescence (center) with Egyptian blue shown in white, and false color image (bottom) with Egyptian blue shown in red.

Learning more about the object’s structure and surface will help inform treatment decisions about this complex figure. Check back to see what else we learn and how treatment will proceed!