Looking inside our falcon mummy

Last Friday, 7 of us from our conservation department took a group of objects from the museum to the GE Inspection Technologies Customer Solutions Center in Lewistown, PA for x-radiography and CT scanning.

Our group gathered around the CT scanner, being operated by Becky Rudolph, GE's North American Radiography Sales Manager for Academia

Our group gathered around the CT scanner, being operated by Becky Rudolph, GE’s North American Radiography Sales Manager for Academia

Now, wait just a second, you might be thinking. Doesn’t Penn have its own x-ray and CT scanning equipment? Why did we have to take these objects all the way to Lewistown for this work? Good questions, and we have a good answer. We just received word that in early 2014, construction will begin on our new conservation labs, which will include a digital x-ray suite. We plan to purchase the x-ray unit from GE, so a visit to their facilities was a chance for us to demo the equipment using some of our own artifacts!

The object I was most eager to image was our falcon mummy. X-ray and CT (computed tomography) scanning technology allow us to “virtually unwrap” this mummy, helping us understand how it was made and what is inside (and as visitors to the lab have heard me say, we can’t assume that there are any falcon remains inside-we can only hope!).

The falcon mummy laying on its storage support on the x-ray plate (within a lead-lined room)

The falcon mummy lying on its storage support on the x-ray plate (within a lead-lined room)

The quickest way to get a peek inside the falcon mummy’s wrappings is by taking an x-ray image. Digital x-ray technology is amazing – with a push of a button, 135 kV (kilovolts, measurement of the voltage), 2.0 mA (millamperes, measurement of the current) and 4 seconds later, we saw this:

falcon xray annotatedHooray! In this first attempt, we could already see that there are bird remains inside. The bright white material concentrated in the center of the mummy wrappings is the skeletal remains. In radiographic images, materials that are denser appear white because they do not allow x-rays to pass through. Materials that are less dense (such as the textile wrappings surrounding the bird bones) appear darker, because the x-rays are penetrating and passing through these materials. We can see in the image above that there are no skeletal remains in the “head” and the “feet” of the falcon mummy – these areas appear to have been sculpted with fabric. The slightly brighter white area near the feet just reflects an overlap of textile in that area.

While we were excited by this image, it immediately prompted more questions. We can see bird bones, but where is the skull? How much of the bird body is present? Are there any clues as to how the body was prepared for mummification? To answer these questions, we turned to the CT scanner.

CT scanning uses x-rays to produce cross-sectional images of an object, which can then be combined to produce three-dimensional views. CT provides a much more detailed look inside objects, and better distinction between different materials.

The CT unit at GE does not look like a medical CT scanner that many people may be familiar with. To scan the falcon, we had to stand the mummy upright in its box, which we then secured to the rotating stage inside the CT chamber with masking tape.

Right: Lynn Grant and I taped the falcon mummy in his box to the stage inside the CT chamber. Left: another view of the falcon mummy's box secured inside the CT chamber.

Left: Lynn Grant and I taped the falcon mummy in its box to the stage inside the CT chamber Right: another view of the falcon mummy’s box secured inside the CT chamber

The CT scanning took a bit longer than 4 seconds, but again, produced much more detailed images. Here is what one of the cross-sections looks like:

falcon cross section annotatedIn this image, the bones are visible as the most radio-opaque materials (so they are bright white). We were also excited to see the feathers, clearly visible as little circles reflecting the cross-section of the feather shafts, which are hollow. The various layers of linen wrapping are also very clear – clear enough to count! But other details are not so immediately clear to us, including the presence of the skull, and exactly how the remains were prepared.

Here is a screen shot from the program we are using to view the CT images, showing 3 different cross-sections, and a basic 3D rendering of a section of the falcon mummy. In this 3D rendering, we can clearly see the falcon’s talons, circled in red!

falcon CT 3 views annotatedWe will need to spend time with the images, and consult other specialists, to better understand what the CT scans have revealed.

image_2

UCLA/Getty graduate intern Alexis North and I puzzle over the CT images of the falcon mummy

We will follow up later with more images and interpretations of the falcon mummy CT scans, plus more about the other objects we were able to examine.

A special thank you to Becky Rudolph and Hank Rowe at GE for spending the day with us, and for their expertise!

 

X-ray excursion

If you stopped by the Artifact Lab this week, you might have noticed that our falcon mummy is no longer on display, and this sign in its place:

falcon signAs indicated on the sign, the falcon has been removed for x-radiography. This mummy has never been x-rayed before, and we’re interested in using this imaging technology to learn how it was made and if there are any falcon remains inside!

Along with the falcon, we’re also going to be x-raying/CT-scanning our (possibly headless) cat mummy, the wooden statue heads, and several other pieces.

We do not have the ability to x-ray and CT-scan objects here in the museum, so we will be taking these selected pieces for a little trip tomorrow. In preparation for their travels, they are securely packed, and ready for this exciting excursion!

The falcon mummy is secured inside its storage support and packed into a larger box for travel.

The falcon mummy is secured inside its storage support and packed into a larger box for travel.

We will update the blog with our findings soon after we return.

 

First step for the heads

Last week I introduced you to two wooden statue heads that I’m working on and promised to share the step by step process of their conservation.

laura blog 2 image3

A first step in understanding these objects is gathering information about their past. As we said in the previous post, they are from Dendera and were discovered in 1898. The other questions were: Who discovered them? How and when did they arrive in Philadelphia? And more…

To address these questions, the best place to begin is the Museum Archives. I first checked Clarence Fisher’s field notebooks, since we know that he excavated in Dendera for the museum from 1915-1918, continuing the work begun by Charles Rosher and Flinders Petrie. An afternoon looking at (all!) of his notebooks revealed no leads. The other possibility was to refer to Petrie’s own field records; and here I found reference to the heads, or more precisely the “statuettes”, noted in his field notebook.

This page notes the “2 statuettes” at the foot of the coffin.
From Petrie Notebook n.15, p.30, courtesy and copyright of the Petrie Museum of Egyptian Archaeology, UCL.

That mystery solved, we moved onto the next one. Included in the storage drawer with the wooden heads, we found a note indicating “2 wooden statuettes nearly consumed by white ants”.

laura blog 2 image2After a little more digging, I found that this was a quote from Petrie’s publication about Dendera, on p.10, paragraph 2…and the rest is still meaningless to us! In this publication Petrie indicates that the heads came from a secondary burial, belonging to a woman, under Adu II’s own funerary chamber.

Moreover, it unveiled a new clue: Petrie wrote that he discovered “statuettes” and not only their heads. That could imply the fact that they were still complete statues at the time of the excavation. It is possible that they were in such a poor condition that the archaeologist left the bodies and only took the heads. We definitely do not have any more parts of these statues in our collection – after checking, no “spare bodies” are registered in the Egyptian storerooms of the Penn Museum.

All of this may seem to be only details but it is essential information for a conservator: the fact that W.M.F. Petrie discovered the heads is highly interesting, because he most likely treated them in the field. He published a book where he explains his practical way of applying a “first-aid” treatment to damaged artifacts (Methods and aims in Archaeology, 1904) which may provide critical information for us! Indeed, knowing this will allow the conservator to be aware of what kind of material was added to the original object and how to deal with it.

My investigation into these old treatment materials will be the topic of a post to come!

 

About two wooden Egyptian heads…

“You have a wonderful job!” It’s a sentence that a conservator often hears. But what is really this incredible job? I propose to you to have a closer look at what a conservator usually does by following step by step the conservation of two artifacts recently arrived in the Artifact Lab.

Laura blogpost1Not really the glamorous objects you imagine when you think about Ancient Egypt, right? But they can reveal so many things to us.

Let’s begin with all what we knew when they arrived in the Lab: these artifacts are two Egyptian wooden statue heads. They bear remains of polychromy (blue and red painting) and have inlaid eyes. In their storage drawer were three labels: one quoting a publication about Dendera (the place where they were excavated) describing the heads, and two others mentioning a previous treatment in 1965 with an adhesive called Vinylite.  Other information about these objects came from our curators, who knew that the heads are from the site of Dendera, more precisely the mastaba of Adu II, excavated by Flinders Petrie, a famous British archaeologist. Moreover, the heads are from the Sixth dynasty (2374-2140 BCE). That’s all we knew about those two heads before beginning our work !

Let’s have a closer look at them…

Left: one of the wooden heads viewed in profile Right: a front view of the other wooden head

Left: one of the wooden heads viewed in profile.  Right: a front view of the other wooden head.

A long quest is ahead and we’re only starting to think about an appropriate conservation treatment. Indeed, before any scalpel reaches their surface, we need to gather as much information as possible about the artifacts. Stay tuned to hear more about our discoveries and the decisions that we make based on what we learn.

 

A new face in the lab

Last week I introduced you to our baby boy mummy, and this week I have another introduction to make. But unlike most of the Artifact Lab occupants, our newest addition is very much alive! Laura Galicier is a graduate student studying conservation at the University of Paris Pantheon-Sorbonne, and she recently arrived in Philadelphia to start a 7-month internship In the Artifact Lab.

Laura_microscope

Laura examining a wooden statue head under the binocular microscope

A couple of the things that you may wonder are, did she know that this internship would involve being on display all of the time, and, as a conservator-in-training, how does she feel about having to answer so many questions about Egypt? Well, the answer to the first question is that she was very well-aware of the open nature of the lab because she found out about us through this blog, and had seen photos of the lab and read about our daily interactions with the public. So she can’t say that she didn’t know what she was getting herself into!

Laura_openwindow

Laura is a quick-study, and is already doing a beautiful job of fielding questions from visitors during our open window sessions.

Furthermore, Laura is more knowledgeable than most conservators about Egypt, because before starting her conservation studies, she completed a Master’s in Archaeology with a specialization in Egyptology. She has also worked in Egypt, at the Karnak Temple Complex.

While she is here at the Penn Museum Laura will be working on several projects in the lab, one which will be the subject of her dissertation. I’m not going to say anything else about it here – I will let Laura tell you all about her work in an upcoming blogpost. In the meantime, I hope your curiosity is piqued by these images (above, at the microscope, and below) of her examining a pair of wooden statue heads. Expect to hear more about them from Laura here on the blog, and if you visit the lab, you may have a chance to chat with her about her projects.

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Laura positioning a wooden statue head under the portable x-ray fluorescence analyzer (pXRF)

Examinations of a baby boy mummy

I think it’s about time we introduce you to a special occupant of the Artifact Lab.

This baby boy mummy, who dates to the Third Intermediate Period (1075-656 BCE), has been in our collection since 1898, when he was donated to the museum by Dr. Henry Shurtleff.

Photograph of the baby boy mummy from the museum Archives

Photograph of the baby boy mummy ca. 1930

In the University’s 1898-1899 Annual Report of the Provost to the Board of Trustees, it states that Dr. Shurtleff presented the infant mummy to the museum on Christmas Day, as an “admirably preserved specimen and an interesting pathological subject”.

It seems that this mummy came into the collection unwrapped – he only has small amounts of textile preserved on his body (and there is currently no evidence that the cloth partially covering his body in the image above is related to his remains, but this remains to be determined). While the fact that he is unwrapped is unfortunate, it allows us to see how well preserved his remains are and evidence of how his body was mummified, including evisceration through an incision on the left side of his torso.

The open incision on the left side of his body reveals a mostly empty body cavity, containing small bundles of linen.

The open incision on the left side of his body reveals a mostly empty body cavity, containing small bundles of linen.

A CT scan in 2009 further reveals how this boy’s body was mummified, and also reveals damage not visible from the exterior. For example, it is clear that his brain was removed, likely through the nose (but due to the small side of his nasal bones it is not possible to see evidence of this). The scan also reveals a large hole in the left lower side of his skull, and the piece of missing bone resting inside his skull.

Two CT still images show the child mummy's skull with a piece of bone resting inside the cranium (left) and the hole on the lower left side (right).

Two CT still images show the child mummy’s skull with a piece of bone resting inside the cranium (left) and the hole created as a result of this loss (right).

Oddly, this damage to his skull is not visible from the exterior, but it may be the result of trauma. His cause of death has still not been determined, but this damage may provide a clue.

The information from the CT scan tells us that this child was less than 2 years of age when he died, based on the fact that his fontanelle (the soft spot) is still open, and also on the development of his teeth.

The open fontanelle on the top of the baby's head is indicated in these 2 images with blue arrows.

The open fontanelle on the top of the baby’s head is indicated in these 2 images with blue arrows.

The excellent preservation of his body is not the only remarkable thing about this baby boy. While examining his remains, we noticed traces of a green substance in areas, including on his face and fingers.

A detail of the green substance under the boy's right eye (left) and an overall view of the boy's face, highlighting the locations of the green substance in green (right)

Left: A detail of the green substance under the boy’s right eye. Right: An overall view of the boy’s face, highlighting the locations of the green substance in a brighter green color.

This substance resembles copper corrosion, and it may either be corrosion from copper that was once in contact with his body (during burial), or may be traces of a green copper-based pigment. How do we know this green substance is copper-based? We tested it with our portable x-ray fluorescence analyzer, which showed high peaks for copper in these areas.

While we’re still working to interpret some of this information, I can tell you one thing for certain: this baby boy mummy sure is special. And if you visit the lab, you just might catch a glimpse of him.

 

Wrapping up the cat mummy

Speaking of Abydos, let’s get back to our cat mummy, which was excavated from a cemetery there back in 1901-02. Our summer intern Anna O’Neill will describe how she carried out the conservation treatment on this very fragile object:

Hello again.  You may remember that last time I wrote about this cat mummy, I got a little distracted.  But this time I’d like to focus on the treatment process.  Many of our mummies are in remarkably good condition, with wrappings that are stable and that can withstand handling (albeit with care).  Not so with this cat.

cat mummy 1When plant-based fibers age, the cellulose that gives them structure decays and the fibers become brittle.  Badly aged linen can fall apart at the lightest touch, leaving loose fragments and powder on the surface of the object.  The linen on top of this cat mummy was torn and obscured by dust, but the real problem was underneath.  Prior to treatment, Molly and I carefully turned the mummy a little so we could see below—and quickly (but gently) put it back!  As you can see in the image below, the layers of linen were falling apart and the threads that had criss-crossed the layers were broken and hanging off.

cat mummy 2We decided to wrap the mummy in nylon netting, which would hold everything in place while keeping the surface visible.  This would be a non-invasive, completely reversible process that would allow the mummy to be safely handled and studied.

Before wrapping, I gave the mummy a light surface cleaning with a variable-speed HEPA-filtered vacuum.  Using a nozzle attachment fitted with a screen, I carefully removed the powder on the top of the mummy.  The linen—though torn—was still soft and flexible, like modern fabric.

cat mummy 3Then, I toned the netting to match the color of the mummy using acrylic paint.  Once the paint was dry, I positioned the netting across the top of the mummy and pinned it in place.  The flip was simple but nerve-wracking—we knew from our quick peek earlier that the underside was in bad shape, but we didn’t know to what extent.  With Molly’s help, I turned the mummy over so that all of the powder, torn linen and broken threads were now on top.

cat mummy 4Since the thick layer of compressed linen powder completely obscured the wrappings below, I again vacuumed the mummy, using a screen to filter out the powder while keeping everything else in place.  A vacuum may seem like an odd conservation tool (I got some weird looks as I hoovered the cat), but with the filter over the nozzle and variable suction control, there’s no danger of sucking up the entire object.

cat mummy 5

The underside of the mummy after cleaning. It may not look like much, but it’s better!

With the underside of the cat finally visible, I sewed the netting up the middle using a flat-felled seam.  As the name implies, this created a neat seam with a flat profile.

cat mummy 6

Overall view of the underside of the cat mummy (after treatment)

Overall view of the top of the cat mummy (after treatment)

Overall view of the top of the cat mummy (after treatment)

Now that the linen wrappings are encapsulated, the little cat mummy can be handled and studied, and it can (hopefully) be x-radiographed this fall.  It still may not have its head, but at least it won’t be losing any more of itself any time soon.

 

Opening Tawahibre’s coffin

I don’t think many people will argue with me about this – a day at work (heck, a day in my life!) can’t really get more exciting than opening a 2500+ year old Egyptian coffin. For the last several months, we have been carrying out treatment to stabilize the loose wood, crumbling gesso, and flaking and powdery paint on the lid of Tawahibre’s coffin. While there is still a lot of aesthetic work to carry out, we finally got the lid to a point where we deemed it stable enough to remove it from it’s base.

Removing the lid from an incredibly fragile 2500+ year old coffin doesn't happen without a lot of planning and discussions ahead of time.

Removing the lid from an incredibly fragile 2500+ year old coffin doesn’t happen without a lot of planning and discussions ahead of time.

Okay, okay, so, the coffin has been opened before, and we knew that there wasn’t a mummy inside anymore (she’s down in storage), but opening the coffin was monumental nonetheless, as the lid hadn’t been removed in decades and we didn’t really know what we would find inside.

Fortunately, we were able to lift and move it without any problems:

DSC_0765DSC_0771DSC_0776(they really make it look like a breeze, don’t they?)

And now the lid is safely resting on a new palette, and the interior of the coffin is revealed to us for the first time:

Tawahibre lid and base separated

Yup, just another day in the Artifact Lab. We’ll fill you in later about what we’re learning and what’s going to happen next.

 

 

Losing it and faking it: investigations into our animal mummies

Hello! I’m Anna O’Neill, a summer intern working in the Conservation Department at the Penn Museum. I’m currently studying to get my MSc in Conservation Practice from Cardiff University in Wales. This summer, I’ve been helping Molly in the Artifact Lab a few days a week and she asked me to write a little bit about one of my projects.

The Egyptians often made votive animal mummies—small, mass-produced animal mummies that pilgrims could offer to the gods. Cats were especially popular as they represented Bastet, the cat-headed goddess of protection, fertility and motherhood. The Penn Museum has several cat mummies in their collection. A few are below:

cat mummiesWe recently started working on E16205, a cat mummy from Abydos (seen below in the image on the left). It was excavated in 1901-02 through the Egypt Exploration Fund through financial support of the Penn Museum, and dates to ca. 381-343 BCE. The linen wrappings are in bad shape—loose, torn and powdery—but that is the least of its problems. After a light cleaning, it became clear that something was missing.

overhead and vertebraAs you can see in the image on the upper right, the linen is damaged and there is a bone exposed at one end of the cat mummy. Zooarchaeologist and Penn professor Dr. Kate Moore confirmed that it’s a cervical vertebra visible at the narrower end of the wrappings.

Dr. Kate Moore examines the exposed cat mummy bone

Dr. Kate Moore examines the exposed cat mummy bone

Animal mummies occasionally lose their heads, as the neck is the weakest point of attachment to the body. Back in March, Molly wrote about our falcon mummy’s floppy head.

In the hope that maybe the head had simply been misplaced, we sent an email to Egyptian Section curator Jen Wegner. A few hours later, Jen turned up in the Artifact lab, smiling and toting a small, tissue-wrapped package. Inside was this little beauty:

Cat head 3quarterIt is evident that this head does not match our cat mummy’s body. The colors and weaves of the linen are different, and the head has carefully articulated features while the body is rather haphazardly wrapped. But the main difference is that there doesn’t appear to be any cat parts within the sculpted wrappings! Inside, the mask contains bundles of linen and resin, but no bones that we could see. A quick look at the records for the head showed that it was X-radiographed in the 1980s and contains “no bony skull”. It is a fake—but an ancient one!

Cat head above below

Additional views of the cat mummy head from above (left) and below (right)

Faking mummies, particularly animal mummies, was not uncommon in ancient Egypt. The materials to make a mummy, like myrrh and natron, were costly. Instead of embalming, the expense could go towards elaborate wrapping and detailing. Once the linen was in place, a religious pilgrim wouldn’t know whether or not there was an actual mummy inside. Several other Penn Museum animal mummies were X-radiographed along with the false head, and it turned out that the middle cat mummy in the image at the very top of this post doesn’t contain any skeletal matter, either. A clue is in the shape of its body—it is wide at the top and narrow at the feet, upside-down in comparison to the real cats.

So, were the mummy-makers pulling the, ahem, linen, over devotees’ eyes?  It is unclear whether the pilgrims knew that the votive mummies they offered to the gods were impostors, and nor do we know if it mattered. The qualities represented by the animal sacrificed may have been more important than its physical body. This way, a fake mummy representing the “idea” of a cat was an equally valid gift as the mummy of a real cat.

We’re disappointed that we can’t reunite our cat mummy body with its head, but Molly and I are going to work to stabilize the wrappings so that it can be CT-scanned and studied. In the meantime, it’s been interesting to see which of the Penn Museum’s votive mummies are real and which are (ancient) fakes.

 

The “conservation story” of Nefrina’s Funerary Mask, Part 3: Stabilization of the Exterior

This is the final installment of the conservation treatment of Nefrina’s Funerary mask.  The condition and stabilization of the interior have been discussed in previous posts.  In this post, I will be talking about building the storage and display mount as well as stabilizing the exterior of the mask.

1.  New mount construction:  Once the interior structural issues were addressed, I made a new mount for the object. I carved Ethafoam, an inert polyethylene foam, to create a support for the top of the head, and used epoxy putty (the black material in the images below) to create a form-fitting rigid support. The clear plastic in the image below is cling film, which I used to keep the epoxy from bonding to the mask while it cured.

The mount is in three separate detachable parts. Part 1 supports the top of the head and the face, part 2 supports the front and back panels of the mask, and part 3 is a stand to hold parts 1 and 2 during travel and storage. Parts 1 and 2 of the mount are supporting the mask at this moment while it is on display (along with a pole mount that has taken the place of part 3).

Left: During treatment photo showing the construction of the top portion of the mount. Right: The completed mount.

Left: During treatment photo showing the construction of the top portion of the mount. Right: The completed mount.

2.  Facing removal: Once I completed the mount and put it in place, I flipped the mask over again and started to remove the temporary facing of Japanese tissue. I removed the facing in sections and stabilized the exposed areas before moving on to a new area. I did this by brushing an area of facing with acetone, which solubilized the adhesive that had been used to place the facing, and then gently pulling the Japanese tissue back.

Facing removal

Carefully removing the Japanese tissue facing

3.  Re-shaping before tear repair: Some of the tears did not go through all of the linen layers, and so could not be treated from the interior. These tears had to be realigned and repaired from the front. As with the inside, I often had to humidify and re-shape an area before carrying out the repair. The images below show the tear in the forehead of the mask during reshaping. I used Teflon tape to bring the edges of the tear together.

During reshaping of the tear in the forehead

During reshaping of the tear in the forehead

4.  Tear repair: I repaired the tears using paper pulp combined with methyl cellulose and powdered pigments. Before applying the wet pulp, I lined part of the areas with a thin sheet of dried paper pulp mixture to achieve an even fill.

Left: lining the area with dried paper pulp and methyl cellulose. Right: After filling tear repair with additional paper pulp mixed with methyl cellulose.

Left: Lining the area with dried paper pulp and methyl cellulose. Right: After filling with additional paper pulp/methyl cellulose mixture.

5.  Edging: Many areas of the paint were adjacent to areas of loss and were cracked and cupped. I stabilized these areas by edging the paint with paper pulp combined with methyl cellulose and powdered pigments.

Side of the mask after edging the areas of unstable paint

Details of the side of the mask after edging the areas of unstable paint

6.  Loss Compensation: Large areas of loss on the edges of the mask also had to be filled for the mask to be structurally stable. I filled the areas of loss by applying pigmented paper pulp mixed with methyl cellulose across the areas of loss using a backing support of silicone-coated Mylar. The coating on the Mylar allows it to be removed once the paper pulp mixture had dried.

Left: During loss compensation.  The square rare earth magnet at the bottom of the image was being used to keep the Mylar in tight with the shape of the mask. Right: After the fill was done and had dried.

Left: Detail during loss compensation. The square rare earth magnet at the bottom of the image was used to align the Mylar along the contours of the mask. Right: After the fill was complete and had dried.

7.  In-painting: Although I had pre-toned the fill material, the fills still needed just a bit of in-painting to adjust the color so that it would blend in better with the mask.

Left: Tear on the head after treatment. Right: Area of loss on the side of the mask after treatment.

Left: Tear on the head after treatment. Right: Area of loss on the side of the mask after treatment.

All of this work allowed Nefrina’s Funerary mask to travel for exhibition in the Reading Public Museum, and to be exhibited here at the museum, In the Artifact Lab – visit us to take a closer look at the mask for yourself, and to see several other objects that have recently been conserved.

- posted by Tessa de Alarcon