Beaded Necklaces: Restringing to Secure the Past

By Tessa Young

Who doesn’t love a beaded necklace?  They’re sold commonly today, but did you know that they were popular in the Ancient Middle East? There are a number of fabulous pieces of beaded jewelry on display in the new Middle East Galleries, and several beaded items from our collection will be featured in the Museum’s Jewelry of Ur lecture and workshop scheduled for June 14th!

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Excavation of a Bronze Age necklace from a burial in the UK (Credit: Suffolk County Council Archaeological Service Contracting Team and Persimmon Homes Ltd [Anglia]) (https://www.futurity.org/shells-necklace-bronze-age-718992/)

When beaded artifacts are unearthed during excavation, typically the floss, or string, which held the beads has disintegrated in the burial environment. To ensure that the beadwork does not lose its original design, archaeologists will document their findings both photographically and through written records, and sometimes, they will string the beads onto a new piece of floss. This floss was usually good enough to get the pieces back to the museum, but it is not up to our modern conservation standards!

B15918 before treatment, with a broken strand and hasty repair tying off the ends

Here at the Penn Museum, when beadwork is destined for loans, display, or requires handling for programming, the Conservation Department wants to be sure that these objects are secure. For the upcoming Jewelry of Ur program, fellow conservation technician Alyssa Rina and I were tasked with restringing several pieces of beaded jewelry, including B15918, pictured above. The floss on this piece was previously broken and then tied off in a quick repair. The plan for this conservation treatment was to restring the beads in a loop with a more durable floss.

Depending on the piece, we restring using two different weights of braided nylon floss, which has the strength necessary to hold the beads securely while also being capable of holding knots. Monofilament (fishing line) is another popular choice, but we have found that knots can come undone rather easily with this material.

Restringing beads in a padded box using a needle in the artifact lab

Penn Museum Conservators have developed several tactics to keep the beads in place during the restringing process. First, we always keep the beads contained within a padded box, preventing the beads from rolling away and getting lost. Second, as seen in the photograph, we typically use a small clamp to secure the floss to the edge of the box. This keeps everything from shifting and rolling around. Finally, we thread the floss onto a small needle to aid in the efficiency of stringing the beads. These beads had large and regular enough holes to use a standard sewing needle, but thin, flexible beading needles are also an option.

Conservators also want to be sure that the stringing will remain in place. The first bead on the string is tied into place with two half-hitches (more-or-less a fancy double knot), and then the rest of the beads are strung into place with the help of a thin, flexible needle. If the beadwork is supposed to be a loop, at the end of the strand, the floss is threaded back through the first bead, and again tied off with two half-hitches. If the beadwork is supposed to be linear, the terminal bead is tied off with two half-hitches, making sure that the beads are tight but comfortable on the strand. Once this is done, the beads are stable enough to be handled or put on display without any fear!

B15918 after re-stringing

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.

#Transformation Tuesday: Getting our Ducks in a Row

The transforming treatment of the Al’Ubaid frieze of three birds (B15883) from the new Middle East Galleries in now complete! (To be more correct, they are probably doves not ducks.) More information about the frieze can be found here. Click here for more information on the exciting new galleries, opening this April!

The frieze before treatment

The frieze after treatment

Originally, the three stone birds (initially called ducks but now identified as doves) would have been surrounded by black shale tesserae and the borders would have been copper alloy sheets. The frieze would have originally looked much like the marching bulls frieze. Unfortunately, neither the shale pieces nor the copper alloy borders made it. The birds had been embedded in a plaster background carved to look like the shale tesserae, and the borders were made from modern machined copper alloy sheets.

The old support system had to be removed due to some condition issues and to prepare the frieze for long-term exhibition. Once taken off, the grimy birds could then be laser-cleaned. The blog post about laser-cleaning them can be found here.

Applying the bulked Paraloid B-72 to the Ethafoam© support

Although the only ‘real’ parts were the stone birds, the curator wanted the entire frieze to be reconstructed to help visitors put the birds in context. It will be displayed next to the marching bull frieze.

After cleaning, the birds were adhered onto a piece of dense archival foam. The black tesserae background was created with Paraloid B-72 (ethyl methacrylate and methyl acrylate copolymer) bulked with glass microballoons and toned with dry pigments. Bulked Paraloid B-72 is stable, reversible, and easily manipulated with either solvent or heat. The shallow lines to make it appear there are tesserae were put in with a heated spatula. The copper alloy borders were also created with Ethafoam© coated in bulked Paraloid B-72 tinted in various shades of green to mimic copper corrosion. The fills in the ducks were inpainted with acrylics to integrate them better.

After all that, the ducks look much happier!

The frieze after treatment and ready for display

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A Columnar Matter Part II: The Conservation Treatment of a 3rd Millennium BCE Mosaic Column from Al ‘Ubaid

By Marci Jefcoat Burton

As a follow up to my previous blog post, conservation treatment of the second of four sections comprising a mosaic column from Tell al-Ubaid, Iraq is well on its way! For a quick recap, the column is dated to 2400 – 2250 BCE (Figure 1). After centuries of burial, the triangular and diamond shaped shell, pink limestone, and shale tesserae (also referred to as tiles), were excavated in 1919 – 1924. The original wooden column interior did not survive the centuries of burial, so after excavation, the tesserae were mounted with plaster to four hollow cylindrical supports of metal mesh covered with burlap. After nearly 100 years, shifts in the internal support have caused structural instability to each section.

Figure 1: (left) Before treatment image of the four column sections stacked together to make a complete column. Image 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) (right) Column section 2 detail, before treatment.

First step of treatment: Remove tesserae from the current support.

The plaster was softened with distilled water applied by brush, then carved away to expose the sides of the each tessera. The tesserae could then be separated from the plaster and burlap backing one by one (Figure 2). Like the first slice of pie, the first piece was the most difficult to remove. Once extracted, access to adjacent tesserae became easier.

Figure 2: (left) Removing plaster surrounding the tesserae with a scalpel blade. Plaster was first softened with distilled water. (middle) Carefully extracting a shell tessera from the plaster. (right) Shell tessera after removal from column section.

The tesserae were removed from the support and placed on an enlarged reference photo in a tray to maintain the order of composition (Figure 3).

Figure 3: All tesserae were removed from the support and placed on top of a rolled out image of the column section to maintain their original placement. All that remains on the exterior of the cylindrical support is a layer of grey plaster and previously filled areas. As a bonus, the Egyptian female child mummy named Tanwa can be seen in the background, just outside of the Artifact Lab window!

Second step of treatment: Cleaning

After removal from column section 2, all tesserae were covered with a layer of powdery plaster, which was removed with distilled water applied with hand-rolled cotton swabs. Medical scalpels were used to gently lift and remove thick remnants of plaster as well as adhesive from previous repairs. In addition, years of dark-brown dirt, dust and grime were removed with distilled water, and Stoddard solvent (a petroleum-derived organic solvent) was applied to the pink limestone and shell pieces to remove greasy grime trapped in the surface (Figure 4).

Figure 4: (left) Removal of adhesive and plaster remnants from a diamond shaped tesserae using a medical scalpel. (right) Shell tesserae being cleaned with distilled water. Note the dark grey-brown grime picked up on the cotton swab.

Third step of treatment: Repair

Once cleaned, tesserae that exhibited breakage such as cracks, detachment, and delamination were repaired with a thin layer of a semi-viscous solution of Paraloid® B-72 (ethyl methacrylate (70%) and methyl acrylate (30%) copolymer) resin in acetone. The majority of the shell tesserae experienced separation between the layers comprising the shell. Some even separated into several pieces, making their reassembly somewhat of a puzzle (Figure 5)!

Figure 5: (left) A triangular shell tessera delaminated (separated) into six pieces. (right) The same shell tessera with all pieces adhered together with Paraloid® B-72.

The shale was even more temperamental to remove from the column section (Figure 6). Shale is a soft sedimentary rock composed of mud, clay, and minerals, such as calcite and quartz. The inherent nature of the shale causes breakage and crumbling. Water can remove particles from the shale surface, therefore these pieces were cleaned with dry brushes and if needed, cotton swabs lightly dampened with distilled water.

The most resilient material was the pink limestone. While some pink limestone tesserae are weathered on the surface, most likely from centuries of burial, these tiles exhibited very little breakage and cleaned up nicely with distilled water and Stoddard solvent (Fig. 6).

Figure 6: (left) A diamond shaped shale tessera exhibiting a lack of cohesion, best observed around the edges, which caused cracks and areas of material loss. (right) A resilient triangular pink limestone tessera with a weathered surface, noted by the lighter, speckled locations. The pink limestone tesserae have strong cohesion and required very little repair.

After a month of cleaning and repair of the shell, pink limestone and shale tesserae, their overall appearance is quite transformative. The tesserae look brighter and truer to their original colors (Figure 7). This is especially the case for the pink limestone, which went from a dark peach-brown, to a brighter light-pink hue.

Figure 7: (left) Shell, pink limestone and shale tesserae after removal from the former support, and kept in their original arrangement. (right) All tesserae after cleaning and repair, ready for re-mounting to a new support.

…..What’s next?

The next phase of treatment for section 2 of the mosaic column is to mount the shell, pink limestone, and shale tesserae to a new solid cylindrical support. More information and updates on the column treatment progress will be featured in an upcoming post, so please stay tuned!

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

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.

 

Conserving Egyptian mummies…and more

Recent visitors to the Artifact Lab may have noticed this new sign posted on one of the lab windows:

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Since we opened in fall 2012, you might have occasionally caught us working on non-Egyptian things, but if you visit us now, you will definitely see us working on things from other parts of the collection, especially artifacts that we are preparing for our new Middle East Galleries. Right now, we are focusing a lot of our efforts on treating ceramics and lithics, most from Iraq and Iran.

We have tens of thousands of ceramics and lithics in this museum’s collection, but somehow, in my over 4 years here, I have gotten away with working on only a handful.

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Conservator Tessa de Alarcon reconstructing a ceramic vessel. This is a common sight in our main lab (behind the scenes) but not so much in the Artifact Lab…until now.

So this is how, after spending over 4 years working on mummies and coffins, working on a small ceramic vessel becomes a novelty. And that is why I am going to walk you through some of the fairly routine steps of treating a ceramic, because I’ve never gotten a chance to write about it on this blog before, and honestly, I’m excited about it.

This small ceramic vessel with a simple striped pattern was excavated in 1931 in Ur, which is a site in modern day Iraq. It dates to the Ubaid Period, so is at least 6000 years old.

31-17-318

31-17-318, before treatment (BT)

As you can see in the above BT image, it was previously broken and repaired. In order to get it ready for exhibition, those old repairs need to be removed. We don’t always remove old repairs (and we never remove repairs that date to when the objects were still in use), but based on observations of the vessel and referencing an old conservation treatment report, I knew that the repairs had to be undone –  if left in place those old materials are likely to fail and possibly cause more damage to the object. Another goal of the conservation treatment is to improve the appearance of the vessel, as there was excess adhesive and overpaint in areas and many of the joins were not well aligned.

Based on that old treatment report and tests in the lab, I knew that the old adhesive is soluble in acetone and that the material used to fill missing areas would soften in acetone enough to allow it to be removed. So the first treatment step, after documenting the piece fully, was to put it in an acetone vapor chamber:

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An acetone vapor chamber isn’t anything fancy – in this case it was created with a plastic bag. I placed the vessel and 2 small containers of acetone in the bag and then clamped the open end to prevent the acetone from leaking out. Sometimes an object only needs a few hours in a vapor chamber before it can be taken apart. This little vessel required 24 hours before even one piece could be taken off. The whole thing was finally deconstructed after a week of sitting in the chamber on-and-off and poulticing and swabbing the joins with acetone.

During treatment, after the first piece detached

During treatment, after the first piece detached

During treatment, after about half the vessel was taken down

During treatment, after more than half the vessel was taken down

Success! All the pieces are finally apart, placed on images of the vessel in order to keep track of everything.

Success! All the pieces are finally apart, placed on images of the vessel in order to keep track of everything.

Once the pieces came apart, I had to swab all the joins with acetone to remove excess adhesive and fill material. I’m now at the point where I will start joining the pieces together again.

Swabbing a break edge of a ceramic to remove excess old adhesive

Swabbing a break edge of a ceramic to remove old adhesive

Stay tuned for more posts about our work on these objects, and our continued work on the Egyptian collection and other projects!