#Transformation Tuesday ft. The Big Guy

By: Céline Wachsmuth

It’s #TransformationTuesday! And that means I get to show off a wonderful transformation that happened right in the Lower Egyptian gallery here at the Museum.

Before Treatment Shot of the Big Guy

After Treatment Shot of the Big Guy

Tah-dah! Looks great, doesn’t it? The Big Guy looks so much better. (I affectionately nick-named this block “Big Guy” because it’s the heaviest block on this side of the wall (it weighs approximately 720 pounds). If you’re in need of some context for this project, check out this Kaipure Catch Up)

Though there isn’t much visible difference between these two photos, in terms of the stability of the block’s surface, much has changed. All in all, this treatment took me about two months to complete and it was quite the journey.

I began my treatment by condition mapping the block in Photoshop and then surface cleaning with gentle vacuuming. Once the dirt immediately on the surface had been removed, I used a variety of sponges and erasers to clean the more stubborn grime. In just these first two steps I realized how fragile much of the surface was. Small flakes would break off easily and not always predictably. Swabbing with a cotton swab was no different and in some cases was more problematic. I proceeded slowly and carefully. Once the Big Guy had been safely cleaned, you could really see his brightly painted surface. The colors were more visible, but so were the fragile and lifting areas. I next faced the biggest challenge of this treatment: how to efficiently and effectively stabilize and consolidate the surface.

Photoshop Condition Mapping of the Big Guy

I began stabilizing all the lifted areas by injecting a dilute adhesive under the surface using an insulin syringe. This worked for some areas but caused some of the surrounding surface to darken. If it came in contact with the surface, the needle also had the potential to disturb it and cause a piece to break off. I then tried to apply the adhesive by brush; I saturated the brush with adhesive and gently tapped the exposed stone next to the prepared surface, wicking the adhesive underneath. This worked but had many of the same issues as the syringe. Both application methods would have taken a substantial amount of time, as almost all of the surface was in need of some consolidation. I began to explore other options for effectively consolidating the surface. In speaking with conservators in the department, we decided to try applying the adhesive via spray canister.

Preval Spray System

Before spraying the entire block, we tested it to see how even the spray application would be and if it would cause any darkening or staining. I was very happy with the tests but thoroughly discussed all the potential shortcomings of this application method with Kaipure project supervisor Molly Gleeson. Spraying the adhesive wouldn’t penetrate below the prepared layer and would only provide superficial consolidation. For those areas that were significantly lifted, I went around with a higher percentage of adhesive and used the brush method of application mentioned above. Once I was satisfied those areas had been stabilized, I sprayed a layer of adhesive on the surface, let it dry completely, and then applied a second layer in areas that were still more concerning. The Big Guy was much more stable and happier but you can’t see any evidence of this because the adhesive is clear!

(I bet if you ask him though, he’d tell you he felt much prettier!)

This figure grabbed a bunch of food to celebrate the Big Guy’s transformation! In actuality, this figure is bringing food for the REAL Big Guy, Kaipure

The Big Guy was almost complete but I had one more task to finish before he would be ready to be handled. Many areas of loss had unprotected edges at risk of being lifted off the surface. Take this area for example, there are quite a few spots with unprotected edges ready to break off with added pressure. 

Detail of unprotected edges

To solve this problem, I edged (put up a protective and supportive layer of material around the exposed edge) those spots with Modostuc. Notice the white spots now on his body?

Can you see the white areas?
Detail of area of edging on figure

I went around to the many places on the Big Guy with unprotected edges and did the same thing. Once I was satisfied all edges had been protected, I painted over all of them with watercolors, a process called “inpainting”. And, if I did my job well, you can’t see it!

Can you find the areas of edging?
Detail of inpainting

The Big Guy is now stable and ready to be moved off-site until the next phase of treatment: re-installing him in the Museum with his many brothers and sisters! This is all part of a larger picture of transformation (for more information on the museum Building Transformation Campaign, click here). It’s a transformation inside a transformation! Inception, anyone?

Two weeks ago, conservator Alexis North posted about one of her recent treatments where the before and after treatment photos are indeed worlds apart and more what you might expect from a Transformation Tuesday post (see her post here). However, don’t judge a book by its cover or an object by its treatment photos! Though you can’t always see the changes, rest assured that once an object passes through conservation it has been changed for the better. Stay tuned for more of our exciting (and perhaps surprising!) Transformation Tuesday series posts!

The Kaipure Conservation Project is funded through a generous grant from the American Research Center in Egypt (ARCE) Antiquities Endowment Fund (AEF) which was established though a grant from the United States Agency for International Development (USAID).

Coming clean

by Alexis North, Williams Project Conservator

The renovation of our Mexico and Central America gallery will involve the conservation and installation of over 200 objects. Some are currently on display in the gallery, but many have never been exhibited before. One of these “new” objects (actually acquired from the World’s Columbian Exposition in Chicago in 1893) is this carved stone figure from Ecuador. It depicts a human man, possibly a king, seated on a throne.

Before treatment views of 12676, a stone figure from Ecuador.

It has an overall dark, somewhat shiny surface. At first glance, it looks like it may have been carved from a smooth black stone like hematite. However, once I was able to look at the figure more closely in the lab, I could tell there was something suspicious about its surface and overall appearance. The surface had a waxy feel, and upon closer inspection, I could see spots of wax on the surface. These waxy areas were very visible under ultraviolet light:

UV fluorescence image of the proper right side of the figure. The bright yellow-white spots are wax.

When I looked at the bottom of the figure, my suspicions were confirmed. Here you can see the bottoms of the feet of the figure and chair, which appear lighter and grey, and much more like stone than the odd waxy sheen of the rest of the surface.

Before treatment image of the bottom of the figure, showing the true surface and appearance of the stone.

I talked to the American section curator, keeper, and other conservators here in the lab, and we all agreed that this type of figure would not have had any sort of surface coating applied during its original use. It is likely that at some point after excavation, the piece was coated to give it more of an even, dark, shiny surface, which was seen as desirable by art dealers and collectors at the time, followed by a wax as a “protective” layer.

In order to prepare this object for display in our new gallery, the old surface coating had to go. It was misrepresentative of the object’s appearance, and the wax was collecting dust and grime. After our incredibly successful gel cleaning workshop with Professor Richard Wolbers, I decided that an emulsion gel would be ideal for removing this old coating.

I started by testing a number of aqueous cleaning solutions in a rigid agar gel. Small punches of gel with each solution were placed on the surface of the figure, and allowed to sit for 20 minutes. The small pores in the agar gel help it act as a sponge, holding the solutions against the surface and pulling the surface coating into the gel using capillary action.

During (left) and after (right) testing different cleaning solutions with a rigid agar gel.

The agar gel samples, after removing them from the figure’s surface.

And the results of my tests were pretty clear! All the solutions tested were successful in removing some of the surface coating (which is unusual!) but Solution A (deionized water with 0.5% citric acid, buffered to a pH of 6.0) clearly pulled the most grime and surface coating away. I performed a second test using Solution A in a xanthan gum gel, which is viscous but not rigid, resists penetration into the surface it is applied to, and has an emulsifying behavior when agitated which helps to pull out and hold on to the material being removed.

I also tested several solvents on the surface, and found that iso-octane would remove the wax, and acetone and benzyl alcohol both cleared some of the grime. I decided to make a xanthan gel mixture utilizing both cleaning Solution A and a combination of iso-octane and benzyl alcohol. This mixture, when tested on the surface, very successfully removed the surface coating better than Solution A on its own, revealing a lighter, gray-green micaceous stone underneath.

The results from testing xanthan gel mixtures by swabbing them on the surface.

Once the cleaning method was identified, it was simply a matter of systematically removing the coating. I worked in sections, by first applying a layer of octamethylcyclotetrasiloxane (D4), a silicone-based solvent which does not mix with water or the solvents used in the gel. The D4 fills the pores of the stone, and acts as a barrier that keeps the gel, solvents, or surface coating from penetrating into the stone during cleaning. Then I brushed on the xanthan gel mixture, and gently agitated it with a paintbrush over the surface to pull up the surface coating. Once the gel had turned a dirty brown, indicating that it pulled up the coating (see below), I removed the gel with cotton swabs and then cleared the area with deionized water. It was an extremely satisfying, if a bit goopy, process.

Left: After the left side of the seat was cleaned using the xanthan gel. Right: The cleared gel, you can see how dirty it got!

And here are some before and after photos of the figure. The difference is so clear! I believe the coating may have been applied to obscure the scratches you can see on the front of the figure, but overall it looks so much better now that the original material is visible.

After treatment images of the figure.

Front view after (left) and before (right) cleaning.

You can see this figure when we open our new Mexico and Central America gallery in late 2018!

Kaipure Catch Up

by Anna O’Neill

Hello again from the “Other Artifact Lab”! It’s been a while since we’ve checked in here from Kaipure’s tomb chapel and a lot has changed in Lower Egypt since the summer. Since June, we have been working to clean and stabilize the painted limestone walls of the Old Kingdom (2415-2298 BCE) mud-brick mastaba tomb chapel for a high-ranking Egyptian official named Kaipure. In the winter of 2015-2016, conservators Emily Brown and Madeleine Neiman worked to disassemble the tomb chapel wall from its wooden 1920s support and performed triage treatments (read more about that here) to keep the blocks safe from vibrations caused by construction next door. This past spring marked the start of the current phase of the project: cleaning and stabilizing the blocks so they can be moved to off-site storage in 2018.

If you’ve been through the Lower Egypt (Sphinx) gallery recently, you may notice some new and familiar faces in the lab. While Céline Wachsmuth and I (Anna O’Neill) have been working on the wall since June, in September we were joined by a third project assistant, Jonathan Stevens. 

The view from our lab space, with two of the blocks reflected in the foreground. We may be biased, but we think we’ve got the coolest lab-mate around.

Between all of us it’s been a very busy fall! We’ve continued to clean and stabilize each individual block from the wall, becoming familiar with some different techniques for cleaning, consolidation, infilling, and documentation, as well as repair methods used by the ancient Egyptians (more on these later). Dr. David Silverman, Curator-in-Charge of the Egyptian Section, stopped by to tell us a little more about the history and imagery of the chapel. We’re also improving our proficiency in fork lift handling as we move the pallets supporting the very heavy stones. Just a few weeks ago, we reached a very important milestone – we officially passed the halfway point, with more than half of the 59 blocks stabilized for their move off-site next year.

A view inside the lab. The largest blocks (up to 700 pounds!) are housed on the red shelves along the back wall; the ones covered in tissue are cleaned, consolidated, and ready to move off-site.

If you find yourself in Lower Egypt any time soon, you are welcome to come watch us work in the lab and read more about the history of Kaipure’s tomb chapel (on our new, informative signage!). While we don’t have open window sessions downstairs, we do occasionally find ourselves in the main Artifact Lab and we’ll be happy to talk about our work then. We’ve got more Kaipure blog posts planned, so keep your eyes open for updates and insights.

The Kaipure Conservation Project is funded through a generous grant from the American Research Center in Egypt (ARCE) Antiquities Endowment Fund (AEF) which was established though a grant from the United States Agency for International Development (USAID).

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.

Cleaning – it’s complicated

by Lynn Grant

Not that long ago, a museum colleague was heard to say “I suppose cleaning counts as conservation” in a doubtful voice. We conservators found this both appalling and amusing as cleaning is a huge part of what we do. And knowing when and how to clean is a big part of our education. Using the wrong methods can permanently damage an artifact. Those of us who finished our conservation training more than ten years ago mostly relied on the rule of thumb ‘try gentlest methods first’. But there have been rumblings in the field about better ways to do things, with terms like Modular Cleaning Systems and Gel Cleaning drifting by. Clearly this was something we needed to know more about.

Richard Wolbers (in blue polo shirt) demonstrates basics of cleaning gel production to Museum conservators and interns

Fortunately for us, one of the ‘rock stars’ of gel cleaning research, teaches nearby at the Winterthur/University of Delaware Program in Art Conservation. Richard Wolbers, who describes himself as a ‘Cultural Materials Engineer’ to reflect his interest in applying new ways of thinking about conservation issues, is Associate Professor at WUDPAC and has graciously lent us his expertise on specific projects previously (one example here). But now that we have so many conservators and interns working on different projects and with a major campaign to reinstall our Egyptian Galleries after 90 years about to start, we asked Richard to give us a two-day workshop on the basics of gel cleaning. This was an abbreviated version of week-long workshops he gives around the world but we certainly squeezed a lot of learning into two jam-packed days.

The conservators and interns get into gel (and emulsion) production!

Richard has basically turned much traditional conservation ‘wisdom’ on its head: looking deeply into the complex interactions among surfaces, dirt, and cleaning materials and using his observations to develop new approaches to cleaning. Even gels aren’t the new frontier anymore; custom made emulsions may allow conservators to use water and solvents in combination when the surface is easily damaged by them when used in liquid applications. Many of the techniques and materials that Richard uses come from the cosmetics and food industries. In fact, as we listened to his explanations, I kept thinking of the Molecular Gastronomy movement. Some of our new cleaning tools have as much relation to our old way of doing things as this does to your grandma’s chicken soup:

Chicken soup spheres (http://jordancaterers.blogspot.com/2013/07/chicken-soup-spheres.html)

It’s a brave new world for conservation cleaning….

Laser cleaning a trio of birds

In addition to the frieze of 6 bulls (which we are still working on in the Artifact Lab), we are also treating a frieze of 3 birds, in preparation for our new Middle Eastern Galleries, scheduled to open in April 2018.

B15883, frieze of 3 birds before treatment

This is a section of a frieze from the site of Al-Ubaid, Iraq which was excavated by Sir Leonard Woolley in the early 1920s. The birds are the only original pieces of the frieze – the rest is a modern reproduction. The birds (possibly doves?) were carved from limestone and each has a pair of drill holes at their center which would have served as an attachment point. Copper alloy twists would have been used to secure the birds in antiquity – fragments of the original copper remain in one of them.

Due to structural stability issues in the modern reproduction, we needed to disassemble the entire frieze. Once the birds were removed, it was evident that their surfaces were very grimy, related to both the burial environment and time in museum storage. A variety of cleaning methods were explored and tested, but none worked better than using our laser.

One of the birds, after removal and before cleaning

The Conservation Department purchased a Compact Phoenix Nd:YAG laser several years ago, and we are still learning about all of its possible applications. We recently had a workshop with conservator and laser-guru Adam Jenkins, which helped us further develop some testing and health and safety protocols.

Essentially, the Nd:YAG laser works like this: the laser emits a beam of light, typically with a wavelength of 1064 nm (in the infrared), which selectively irradiates and removes unwanted dirt and surface coatings without damaging the object (a process called laser ablation). This type of laser cleaning works well for removing dark substances from light-colored objects, so trying it on one of the birds made a lot of sense.

Easy for me to say. I didn’t do this treatment – project conservator Madeleine Neiman did. So she gets all the credit for this.

After testing, Madeleine carried out her first laser cleaning treatment on the bird in the image below. Here she is getting set up to carry out the work:

And here is a shot of the bird after the surface was partially cleaned: (WOW!)

I think the process and results are best displayed in a gif, or a video, so I’m including the gif below, and here is a link to the video.

Go Madeleine! I think this was a really rewarding treatment to carry out. Please take note of all of the PPE (personal protective equipment) involved, including special eyeware and ventilation.

A lion relief from Nippur

Yesterday we received a new artifact in the lab: this terracotta lion relief from Nippur, Iraq.

B20014: the lion relief in fragments

Some may argue that this object could be a candidate for the Ugly Object of the Month club. Well, we like him, and one of our conservators pointed out that he looks a lot like one of these wonderful characters from William Steig’s Rotten Island.

Illustration from William Steig’s “Rotten Island”. Image courtesy of scienceblogs.com

This relief was excavated in the University of Pennsylvania’s Babylonian Expedition to Nippur in 1899. Like the Nippur slipper coffin currently on display in the Artifact Lab, it was previously repaired with metal staples and (at least one type of) adhesive, likely around the same time as the slipper coffin.

The staple-like wire tires used to repair the relief are visible in this view of one of the break edges.

More evidence of the old repairs on this fragment.

Getting this relief ready for exhibition in the Middle Eastern Galleries will not only require significant conservation treatment, but also a custom mount so that it can be displayed safely. We will provide updates as we work on this.

Update from the Gordion Excavations

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.

In my last post, I introduced the Gordion Archaeological Project and what I’ve been up to as a conservation intern here. The season has continued at a quick pace, with a steady stream of incoming small finds and projects at the Gordion Museum.

While some objects only require a light cleaning, others can take a few days to process. I mentioned two pairs of copper alloy tweezers, and second pair has now been fully treated. In addition to mechanical cleaning, the copper alloy object was treated with the corrosion inhibitor benzotriazole, also called BTA. Objects are immersed in the solution and placed in a vacuum chamber to ensure effective application. The corrosion inhibitor is then protected by a coating of dilute acrylic resin. After these treatment steps, any structural breaks can be reconstructed and joined with an adhesive. For objects with weak points that may be susceptible to further breakage, small supports can be added to the housing. Here I included an Ethafoam support with a cavity cut out to hold the pair of tweezers.

Copper alloy objects are rinsed with acetone prior to treatment with BTA, a corrosion inhibitor.

Copper alloy objects drying after treatment. This group includes an arrowhead, a fibula, tweezers, and a decorative fitting.

Another example is this small ceramic figurine fragment. In this case, the female figure has a stable structure but a very delicate pigmented surface. The pigment was consolidated with a dilute adhesive mixture, applied by pipette to avoid any action on the surface. To further protect the surface, the figure was cavity packed with a layer of smooth Tyvek, which will prevent abrasion and further pigment loss.

Ceramic figurine fragment in protective housing, made from an Ethafoam cavity with smooth Tyvek barrier.

Processing small finds often involves unexpected discoveries. While working on a small ceramic vessel, I was interested to learn what was contained inside. One of the best parts about working on site is the opportunity for immediate collaboration. After talking about the soil samples with an archaeobotany student, I knew to expect small bones in the vessel interior, potentially from a mouse. After pulling out many, many vertebrae and rib bones, I consulted our zooarchaeologist to figure out what the bones may be. There were no signs of a skull, which likely deteriorated further due to its fragility. However, the other bones indicated not a mouse but a snake coiled inside the vessel. We can’t say what the snake was doing there, but all the associated bones and soil will be kept for potential further study.

Excavating the interior of a small intact jug.

Small rib and vertebrae bones, likely from a snake, from the interior of the jug.

During the season, we’ve also had some very large finds in the active excavation areas. This includes a large ceramic pithos that was found almost completely intact. In this case, conservation made several site visits to consult about techniques for supporting and lifting the object. After padding the interior of the vessel, we added supportive wrapping over a thick layer of dirt that was left as protective casing. This process helps minimize damage from physical forces and also keeps fragments in place if they happen to detach.

As I get ready to wrap up my time here at Gordion, I was lucky to have the opportunity to see the site from a new perspective. Along with several colleagues, I was able to take a hot air balloon ride over Yassıhöyük and some of Gordion’s many burial mounds.We enjoyed magnificent aerial views of our workspace!

Aerial view of the citadel mound with active excavations.

Two human figurines from Tureng Tepe

Preparations for the opening of our new Middle Eastern Galleries are well underway. Take a peek into either of our lab spaces (both the Artifact Lab and our main lab spaces) and you’ll see a multitude of artifacts being treated for this upcoming exhibition.

I recently treated two ceramic human figurines which will be going into a case with several other figurines from Tureng Tepe, a site in northeastern Iran.

Map of archaeological sites in Iraq and Iran, with a red star next to Tureng Tepe. Base map image credit: University of Chicago.

One is female, and mostly complete, and the other is a male torso.

Like most objects for the Middle Eastern Galleries, both of these objects needed treatment. And they represent two different reasons for treatment, which we commonly seen in our lab.

The female figure had a couple different problems. First, and most obviously, her head was detached.

A detail of 32-41-68, before treatment.

The other problem stemmed from the fact that she had been treated before. In the 1980s, she was desalinated by soaking in water, and consolidated with PVA-AYAF, a polyvinyl acetate resin. Both of these interventions were important for the long-term structural stability of this piece. But the problem related to old treatment was an aesthetic one – there were areas on the body that were very discolored/gray, which made for a splotchy appearance overall. You can see these gray patches in the images above. These gray patches were also very shiny, and were related to a coating that had been applied to the figure at some point – possibly the old PVA consolidant.

Treatment of this figure included removing the darkened coating by swabbing with acetone, and some mechanical removal with bamboo skewers. The head was reattached with Paraloid B-72. There were some areas where the ceramic body was flaking and these areas were consolidated with a dilute solution of Paraloid B-72 in acetone and ethanol.

32-41-68 before (left) and after (right) treatment

In contrast, the male figure had never been treated. When I first laid eyes on him, I thought to myself, “Terrific! This piece looks like it will just involve documentation. It will be in and out of the lab within a day or two.” Well, looks can be deceiving, and I quickly realized that the male figure had a soluble salt problem, related to the burial environment. I actually haven’t discussed soluble salts on this blog before. You can read a nice explanation of soluble salts, how they affect archaeological objects, and what we do about them, in Tessa de Alarcon’s blogpost on the Penn Museum blog.

The most obvious signs of soluble salts were the small flakes of ceramic sitting under the figure in its storage support. A quick spot test for chlorides was positive, so I made the decision to desalinate the figure by immersion in water for several days. After desalination, I readhered the small flakes, and the treatment was complete.

Before (left) and after (right) treatment images of the male figure from the side. Small flakes were reattached in the area indicated by the red arrow.

32-41-62 before (left) and after (right) conservation treatment.

As I mentioned, these artifacts will go into a case with several other human figurines from Tureng Tepe. We have, or will be treating a number of figurines from several different sites for the Middle Eastern Galleries. I am including images of some of these figurines below. Personally, I like the ladies with their hands on their hips.

Human figures. Link to larger images and more information by clicking on their numbers (listed from left to right): 32-41-25, 31-43-450, 43-29-3, 58-4-3, 31-16-733, 31-16-734

A final look at Ptah-Sokar-Osiris

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.

When we last checked in with the Ptah-Sokar-Osiris figure, I was working on finding a satisfactory cleaning approach. The figure has a darkened layer over the front surface, which obscures the beautiful patterns, colors, and hieroglyphs. My goal for cleaning was to clarify designs and improve legibility, although the sensitivity of the paint layers has made this an interesting challenge.

After cross-section analysis, I looked into instrumental techniques to better understand the condition issues. One promising technique was gas-chromatography mass-spectrometry (GC-MS) since the darkened layer was potentially a coating material. I took a sample by swabbing the dark layer from the wood substrate. Since only a small amount of material can be gathered this way, I collected several swabs in a glass vial for analysis. I sent this down to Winterthur Museum’s Scientific Research and Analysis Laboratory (SRAL), which has previously collaborated on samples from the Artifact Lab. Dr. Christian Petersen, a GC-MS specialist, sent back my spectra with some interesting results. He described the mixture as “waxy dirt,” which helps to clarify what likely happened to the surface. Wax may have been applied to consolidate the badly flaking paint, and this layer could have trapped dirt over time as the figure rested face-up in storage.

Focusing on the wax component did not immediately produce better cleaning results, and I continued testing gels with variations on solutions, application method, and timing. I eventually tried an application of Pemulen TR-2 gel, a polymeric emulsifier, with a proportion of solvent added. This gel was more effective for lifting the waxy grime and did not require excessive action on the surface. Used along with a silicone solvent barrier layer, I was able to lightly clean without lifting pigments from the surface. While I had some initial ideas about cleaning, this method was something that I only found through the process of trial and error.

L-55-29 detail, cleaning test

Even though I cleaned slowly in very small sections, the actual treatment step took much less time than the research, testing, and planning phases. Take a look at the results below.

L-55-29, before cleaning (left) and after cleaning (right)

Aside from cleaning, a few other steps were taken to stabilize the statue. The headdress, which is constructed from multiple pieces of wood, had a large gap that allowed the pieces to move individually. To add support and decrease movement, removable fills were made from Volara foam and Japanese tissue. These materials were turned into small “pillows” that were then pressure-fit into place.

L-55-29 headdress, shaping and fitting Volara foam fills

The figure, headdress, and base do not fit together in a stable arrangement. Instead of intervening further with the object itself, an exterior mount will be constructed to hold the components in place. This method has worked well with a similar Ptah-Sokar-Osiris figure, which you can see displayed in the Upper Egypt Gallery!

Another Ptah-Sokar-Osiris figure on display in Upper Egypt, showing the back of the figure and the mount holding the three pieces together.

Overall, this project provided quite a few challenges and an opportunity to explore cleaning techniques. Thanks for following along on this experience with Egyptian painted surfaces!