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.

 

Unwrapping mummies?

If there is one thing that I try to emphasize to visitors to the Artifact Lab, it is that we are NOT unwrapping or cutting open mummies. While this type of examination may have been appropriate and acceptable in the past (think PUM I) we don’t do this anymore. As you may gather from the title of this blog and our project, we are focusing on the conservation of our mummies, and we do this by aiming to use non-invasive and reversible examination and treatment techniques as much as possible. Our ability to carry out our work with much less interventive procedures than those used in the past is due in part to advances in technology. And when you see what is possible with new technology, you can see why autopsying mummies just doesn’t, errr…cut it.

Take, for example, one of our mummies that was CT-scanned back in 2009.

Hapi-Men on display in the Secrets and Science exhibit

Hapi-Men on display in the Secrets and Science exhibit (Hapi-Puppy is by his feet!)

As part of a larger CT-scanning project funded by the National Science Foundation, Hapi-Men, along with his puppy (Hapi-Puppy) was CT-scanned at the Department of Radiology at the Hospital of the University of Pennsylvania (HUP) (a special thanks to Felicia Williams and Erica Durham for this work!).

Although Hapi-Men had been x-rayed in the past, this type of examination is limited in that it does not provide much detail of any of the preserved soft tissue and other materials (like amulets) included in the mummy’s wrappings. But CT-scans can help reveal these details, and they also allow for 3D reconstructions, like the one you can see below, created by Penn graduate Samantha Cox under the supervision of Dr. Janet Monge.

CT-scanning, combined with other imaging techniques such as photogrammetry and laser scanning, leads to some pretty amazing virtual representations of mummies. Most recently, such work has been carried out in a collaborative effort between The Museum of Mediterranean and Near Eastern Antiquities in Stockholm, a group of Swedish visualization researchers, FARO (a 3D technology company) and Autodesk (a software company focusing on 3D design). This collaboration has resulted not only in the capture of new information for researchers, but the creation of an interactive exhibition for museum visitors, scheduled to open in Stockholm in February 2014. The interactive part of the exhibit, created using Inside Explorer will allow both museum staff and visitors to use simple gestures to virtually unwrap the mummies and to explore their multiple burial components.

You can read more about this exciting project, and see several images and videos of the process by following this link.

Our current work to conserve the mummies and funerary items In the Artifact Lab will stabilize some of these fragile objects enough to allow us to CT-scan them, and hopefully so that we can create some of our very own interactive exhibition features in the future.

 

An introduction to our child mummy Tanwa

In my recent post about the Philadelphia Science Festival, I put in a little teaser photograph of one of our child mummies currently in the lab:

child mummy overallNow, all of our mummies are special, but this child mummy has several qualities that make her particularly endearing. One of the things that we really love is that her name is written on her wrappings, near her feet.

Child mummy detailHer name is actually written in both Greek and Demotic – Demotic is the language/script that developed in later periods in Egypt (and is one of the languages inscribed on the Rosetta Stone, along with Greek and hieroglyphic Egyptian). In Greek, this┬áinscription┬áreads: “Tanous (daughter of) Hermodorus”. In Demotic her name reads as “Tanwa”.

So, based on this inscription, we know that she dates to the Ptolemaic Period, and that she is a girl. According to our Egyptologists, what is interesting about the names is that they give a good indication of the multi-cultural nature of this time period. Not only in the fact that 2 languages are represented, but that the girl’s name incorporates the name of an Egyptian goddess, Iwnyt, while her father’s name includes the name of a Greek god, Hermes.

Tanwa has been CT-scanned, which has confirmed the fact that she is a girl, and was likely right around the age of 5 when she died.

Here is a still from the CT scan showing a detail of Tanus' skull. Based on her teeth it has been estimated that she was right around 5 years old when she died.

Here is a still from the CT scan showing a detail of Tanwa’s skull. Based on her teeth it has been estimated that she was about 5 years old when she died. That pin you can see near the top of her skull is modern and not actually in her skull-it was used to secure the outermost layers of linen in that area.

One of my favorite things that CT scanning has shown is that she is wearing 2 bracelets on her left wrist. We are guessing that these might be gold.

Two bangle bracelets on the left wrist show up clearly on the CT scan.

Two bangle bracelets on the left wrist show up clearly on the CT scan.

She also has a small metal ball included in her wrappings just over her right tibia. Exactly what this is and why it was placed there is a bit of a mystery.

A detail shot of the metal ball near her right tibia.

A detail shot of the metal ball near her right tibia.

There is a lot more we can learn from these CT scans, which I will describe in a future post.

Fortunately, Tanwa is in fairly good condition; one of the main issues that we need to address here in the conservation lab is that many of the narrow linen bands wrapped around her body are fragile, torn and partially detaching. I am currently more than halfway through the conservation treatment, and I will provide a thorough report on what we are doing to stabilize her wrappings next. Stay tuned!

 

Bobblehead no more: finishing the falcon mummy treatment

As you’ve seen in one of my latest posts, I have been working on the treatment of our falcon mummy, but of course I saved one of the most challenging parts for last. I couldn’t capture a great photo of this, but one of the biggest condition problems with the falcon is that he had a seriously floppy head. This was caused by tears, breaks and losses of the linen fabric in both the front and the back of the body, just below the neck.

Two detail shots of the falcon mummy before treatment, showing breaks and separation of the textile near the neck

Actually, one of the best images showing this is in our online collections database found by following this link. It is evident that there was nothing supporting the falcon’s head in this photo, allowing it to fall backward.

To stabilize this area, I filled the gaps using Japanese tissue paper and methyl cellulose, the same adhesive I used to repair the textile on the feet of this mummy. Japanese paper is commonly used in conservation for the repair of artifacts and paper-based materials. As the name implies, this is paper made in Japan, usually from kozo fibers, which come from the inner bark of the Kozo, or Paper Mulberry tree.

Gap in back of the falcon’s neck during (left) and after (right) filling and mending with Japanese tissue paper.

In areas where the Japanese tissue paper would be visible, I toned the paper beforehand using Golden acrylic paints. I made most of the fills from the back, which allowed the separated area in the front to join together nicely, requiring little additions in this area.

Two views of the falcon mummy after treatment

Many of the dark-brown dyed linen elements were also very fragile and actively detaching, so I consolidated them using a 2.5% solution of Acryloid B-72 in a 50:50 solution of acetone/ethanol. Finally, I created a storage support for the falcon – even though the head is no longer floppy, this will provide important support under the head to reduce stress in this area and to avoid continued damage or failure of the repair.

Falcon mummy after treatment, with new storage tray

The falcon mummy is now ready for transport over to the hospital later this year for CT scanning. CT scanning will be able to tell us if there is a falcon inside the wrappings, and will also provide important information about how these animal mummies were made. Additionally, the CT images will be an important part of my conservation documentation – I will be able to annotate which materials I added as part of the treatment process, to eliminate confusion over what is original and what is not.

Our falcon mummy will also be going on display later this year – and you can visit him anytime by stopping by the Artifact Lab!

 

The mystery of the mummified heads

Another frequently asked question In the Artifact Lab is, “what’s the story with those mummified heads, and where are their bodies?”.

A disembodied, but completely wrapped mummified head in the Artifact Lab

Well, it is a bit of a mystery, and we don’t know why these heads are detached from their bodies, exactly.

We have 5 heads in the lab right now, all without any other remains. While two came in as gifts to the museum, the other three were collected by excavation, and all have been in the collection since the beginning of the 20th century. One, the head above, is still completely wrapped. The others are mostly, if not completely, missing their bandages but still have impressions of their linen wrappings and other residues from the mummification process remaining on the preserved skin, hair, and bones.

One of the unwrapped heads, showing evidence of the mummification process. In the Graeco-Roman Period, gold leaf was used to decorate parts of the body, as seen on this man’s head.

Close examination of these heads can provide some clues as to how they became detached. The head in the first image above, for instance, is still wrapped and there is a clean cut through the wrappings-this could not have happened by mistake or through deterioration-it had to have been cut off. Cut marks are also visible on another head-on both the bone and the preserved skin.

The wrapped head, showing the cross-section of the cut linen bandages around the neck. Human remains are preserved inside.

Why were these heads cut off? That’s also unclear, but it is very possible that the heads were severed as a result of looting. Bodiless heads have been excavated from tombs that clearly have been robbed and looting has been cited as the cause of these disturbed remains.┬áInvestigations in our archives may also reveal other clues-if we find anything we will provide an update!

While we may never be able to find out who these people were, there are things to discover from their remains-the heads can be CT-scanned in order to understand more about the mummification process (as seen in this study done at the MFA in Boston), determining sex if unclear, and possibly help in figuring out cause of death. DNA analysis may also be possible. Again, we will provide updates as we learn more. To read more about previous CT-scanning done at our museum on other Egyptian mummies, follow this link.