Conserving a child mummy

Posted on May 15, 2013 by mollygleeson

A couple weeks ago, I introduced you to our child mummy Tanwa, and now I’m happy to report that I’ve completed her conservation treatment.

Tanwa before conservation treatment

Tanwa has been in our collection since 1898; she was collected through the American Exploration Society, an organization founded by Sarah Yorke Stevenson, the museum’s first curator of the Egyptian section.

Tanwa was exhibited in the museum early on, but she has not been on display for a long time. When she came up to the Artifact Lab, we could see that she was generally in good condition, expect for the fact that some of the narrow bandages wrapped around her body, especially those around her feet, were fragile, torn, and partially detached. Many of the strips on the underside of her body were also damaged – although these aren’t usually visible since Tanwa is always lying on her back, they are at risk of detaching with any movement or handling.

Details of damaged linen around the feet (left) and on Tanwa's back (right)

Details of damaged linen around Tanwa’s feet (left) and on her back (right)

After fully documenting Tanwa’s condition, I first removed excess dust and grime from the surface of her wrappings using a soft-bristled brush and a HEPA-filtered vacuum. Cleaning the exterior surface significantly brightened the linen, and I think at this point Tanwa was already looking much better.

Tanwa had a few straight pins stuck into her wrappings in areas, apparently as a measure to temporarily secure some of the fragile linen. I removed all of these pins and adhered the linen in place as necessary with small amounts of methyl cellulose adhesive.

A pin stuck into the bandages on Tanwa’s head (left, indicated by red arrow) was removed and the linen was secured to prevent further loss (right, after treatment)

I then proceeded to repair the linen around her feet and in all other places where the linen was fragile and at risk of detaching or becoming further damaged. All repairs were carried out using similar materials and methods to those I used to repair our falcon mummy. Distorted linen was relaxed and reshaped by humidification with either a damp blotter and Gore-tex sandwich, or using the Preservation Pencil. Detached linen was tacked down using a 6% solution of methyl cellulose adhesive, and fragile areas of linen were backed/supporting using Japanese tissue paper toned with acrylic paints.

Backing a fragile area of linen with toned Japanese tissue paper – the blue clamp is holding everything in place while the adhesive dries

Here are some after treatment details to compare to the before treatment shots seen in the second image on this post:

After treatment details of the linen around Tanwa’s feet (left) and on her back (right)

All of Tanwa’s linen wrappings are now fully stabilized and she is ready to be exhibited for the first time in decades!

An overall view of Tanwa, after treatment

Tawahibre all tied up

Posted on April 13, 2013 by mollygleeson

When I wrote about the fantastic image we retrieved from our Archives a couple weeks ago showing our Mummy Gallery in 1935, I promised to provide an update on the treatment progress on Tawahibre’s coffin.

Well, why don’t I start with this:

A view of Tawahibre’s coffin from above

While you may not be sure what you’re looking at here, this looks like progress, doesn’t it? I’ll tell you what you are seeing – the coffin is tied in several places with cotton twill tape, holding small pieces of white Volara foam and blueboard (acid-free, lignin-free corrugated board) in place against the coffin surface.

A detail of the Volara foam and blueboard held in place with cotton twill tape

The purpose of this system, other than looking kind of intriguing, is to place select pressure in areas on the coffin (whenever I say this I always think of the useful book The Gentle Art of Applied Pressure-the title speaks for itself). As I have described previously, the coffin is pretty distorted in areas, due to the fact that many of the individual wood elements have separated and moved apart and that the plaster has separated from the wood substrate. We are trying to realign these pieces as much as possible using humidification with a Preservation Pencil, which allows us to direct a small stream of warm humidified air in select areas, which helps the plaster and wood relax a bit and encourages movement. Once we get an area to move sufficiently, we then apply pressure to the area to hold everything in place.

Here Nina is directing a stream of humidified air with the Preservation Pencil and I am applying pressure with my hands.

We’re also continuing to consolidate the painted surface and readhere loose pieces of plaster and wood.

We don't usually work in teams, but yesterday we had a little group humidification and consolidation party!

This treatment has been a team effort, and yesterday we had a little group humidification and consolidation party!

While we’re making progress and becoming pretty comfortable with the coffin and the treatment, there are still some scary areas to deal with. This is an area that I’ll be tackling next:

A detail of a badly damaged area on the coffin, showing significant cracking and flaking and detached and displaced fragments

Wish us luck as we continue this work!

Salvaging PUM I’s chest wrappings

Posted on April 6, 2013 by mollygleeson

This week, I started to work on the treatment of our mummy PUM I‘s linen wrappings. Poor PUM I – not only is his body quite deteriorated and in multiple pieces, but his linen wrappings are also fragmentary and very fragile. Some of linen in the worst condition are the pieces that once covered his chest, which were cut off during the 1972 autopsy.

This rectangular section of textiles was cut away as a single unit during the 1972 autopsy.

In addition to the mechanical damage caused by the autopsy, the linen has suffered from insect damage and it is significantly stained and embrittled in areas, likely due in part to deterioration of the human remains they were once in contact with.

Removing the wrappings (left) and the chest wrappings after removal (right)

While this linen is in poor condition, it can be moved as a single unit, so we removed it for treatment. The goal of the current treatment is to keep the linen layers in this section together; to prevent them from slipping out of alignment and to prevent the linen from continuing to tear and deteriorate even more.

After vacuuming the linen thoroughly, I got to work relaxing distorted areas and realigning tears.

Local humidification of the linen in progress, using damp blotter and Gore-Tex

To realign tears, I bridged these areas from behind with small pieces of Japanese tissue paper, adhered in place with methylcellulose adhesive. The methylcellulose works well because it sets very quickly with only a small amount of pressure from my finger or a spatula.

One side of the wrappings before (left) and after (right) humidification and tear repair

The other side of the chest wrappings before (left) and after (right) tear repair

This is only the beginning of the treatment on PUM I’s wrappings, but I think they are already looking better!

From the Archives

Posted on April 3, 2013 by mollygleeson

The Penn Museum Archives is an incredible resource for us here at the museum.

A view into the Penn Museum Archives

When we begin working on objects in the conservation lab, we carry out preliminary research, which often includes searching for related materials in the Archives. Among the materials we may be interested in are archaeological field notes, letters between curators and archaeologists or collectors about the acquisition of specific artifacts, and old photographs.

Recently, Senior Archivist Alex Pezzati scanned some images for me, including this one, a shot of the Egyptian “Mummy Gallery” in 1935.

I was excited to see some of the artifacts we’re working on in the Artifact Lab right now in this photo. Can you pick some of them out? In the image below I’ve circled some of them in red.

The objects circled in red above are either being worked on in the Artifact lab or are on display in our accompanying exhibit

These old exhibition photographs can be extremely valuable to conservators. Not only does this particular image tell us that certain artifacts were definitely on display, and when (which may not be recorded elsewhere), but it also shows us how they were displayed. In some cases, seeing the way that artifacts were previously displayed may help to explain damage, such as excessive fading on one side or adhesive residues left behind by an old mount. We can often make good guesses about this type of damage, but it’s always nice to have some proof!

What particularly excited me about this photograph is that it shows the coffin of Tawahibre in the gallery. We are currently working on this coffin in the lab, but it is still too fragile to separate the lid from the base to allow for examination of both pieces individually.

The coffin of Tawahibre in the Artifact Lab.

Just recently, Curator Dr. Jen Wegner was up in the lab and we were discussing the coffin and some of my observations, and she wondered out loud if the back had any text written on it. I had wondered the same thing myself but I knew that until we carried out further work, we wouldn’t be able to know.

BUT, since this 1935 photograph shows both the lid and the base of the coffin on display, we don’t have to wait any longer!

The lid and the base of Tawahibre’s coffin, side by side in the Mummy Gallery in 1935.

As you can see in the above image, there is writing on the back! Now only if we could just hasten the conservation treatment so we can examine it for ourselves…

Another thing that is useful about this image is that is shows that much of the damage we’re seeing on the coffin today was present in 1935. This includes both major structural damage and extensive paint loss in areas. It is likely that the coffin came into our collection with this damage, which is somehow reassuring to me. I will also note this in my documentation.

Tawahibre’s coffin in 1935 (left) and today (right). Much of the major damage we see today had already occurred by 1935. To highlight this, I’ve circled some of the damaged areas in red in both images.

We continue to plug away on the treatment of the coffin and we are hoping to soon reach the point where we can separate the lid. I will provide an update shortly about some of the more recent work we have been carrying out on this artifact!

New discoveries

Posted on March 22, 2013 by mollygleeson

When “In the Artifact Lab: Conservation of Egyptian Mummies” was envisioned, we knew that there were a lot of unknowns – the idea was that this would be a working lab, so we would be carrying out much of the work that normally goes on behind-the-scenes to prepare objects for exhibition, in full public view. Many of the artifacts selected for examination and conservation in the lab had not been examined very closely for a long time. What we did know is that we needed to do a whole lot more research, documentation, and conservation on these pieces before they would be ready for display.

We’re not just trying to look good-we’re actually working!

Anyone who has been following this blog knows that we have made several discoveries about some of these artifacts – the discovery of the fact that our mummy PUM I had a beaded shroud, for instance. Another artifact, or assemblage of artifacts actually, that we knew we’d be learning much more about is the outer coffin of Ahanakht.

One of the boards from Ahanakht’s outer coffin, showing the side covered with columns of Hieratic inscriptions.

We currently have 15 pieces (all dissembled) from this coffin up in the Artifact Lab, and 2 more are on exhibit. We also have Ahanakht’s inner coffin, which is assembled and on exhibit here on the 3rd floor of the museum as well.

Ahanakht’s inner coffin on exhibit in the museum

Previously on this blog we posted some photos of some of the smaller “coffin boards” – or at least, that’s what we thought they were. There are 4 of these smaller boards and they were acquired with the other pieces of the outer and inner coffins. They are made of the same wood, have similar bands of hieroglyphs on one side, and have similar construction methods as the larger boards.

3 smaller pieces previously thought to be part of the outer coffin

These boards haven’t required extensive conservation – so other than some examination and very minor treatment, most of the work on them so far has been curatorial.

Curator Dr. David Silverman has been working with Penn graduate student Leah Humphrey to transcribe and translate all of the inscribed text on the coffin boards. Dr. Silverman has determined from the text on 3 of the smaller boards that they are actually a part of a canopic box, not a coffin. These wooden containers usually were square in shape and held 4 jars, each of which had one of the 4 mummified parts of the deceased: the lungs, liver, stomach, and intestines. The 4th small board, however, remains problematic since its dimensions make it clear that it does not belong to either of the 2 coffins of Ahanakht. In addition, its size and the nature of the text inscribed on it, make it also clear that it is not part of the canopic box. Its text indicates that it is part of yet another coffin.

Examination of one of the canopic box pieces and the “mystery” board underway

Research progresses in the hopes that we can figure out where/what the 4th mystery piece is from. This particular project is a good example of how “In the Artifact Lab” is an exciting and sometimes perplexing work-in-progress.

Bobblehead no more: finishing the falcon mummy treatment

Posted on March 16, 2013 by mollygleeson

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!

Special visitor to the Artifact Lab

Posted on March 13, 2013 by mollygleeson

Last week, we had a special visitor in the Artifact Lab. We recently managed to track down the person who performed PUM I’s autopsy – Dr. Michael Zimmerman. Back in 1972, Dr. Zimmerman was head of pathology at the University Hospital, and PUM I was the first mummy he helped autopsy at the Penn Museum (and one of the first mummies to be autopsied in this way in the world). Dr. Zimmerman went on to receive a PhD in anthropology and is now well known as a paleopathologist who has studied over 200 mummies from around the world.

Dr. Michael Zimmerman performing the autopsy in 1972 (left image, on left) and just last week, visiting PUM I in the Artifact Lab

We posted more information about this on the Museum blog last week. For those of you who didn’t see this article, please check it out! You can access it by following this link.

Outside of the box: freeing a wall painting fragment from its frame

Posted on March 1, 2013 by mollygleeson

Exciting day in the Artifact Lab! We finally freed this wall painting fragment from its old frame-a frame that it has been in since before coming into our collection in 1925.

Wall painting fragment from Deir el-Medina, before treatment

You can read a bit more about this object in a previous post by following this link.

For the last several weeks I have been preparing for this task – I have spent a lot of time examining the painting, documenting its condition, and analyzing the materials used in its construction. I have carried out some cleaning tests and consolidated much of the painted surface. I also dug out a lot of the cracked and loose plaster surrounding the painting, so that I could fully understand how the painting was set into the frame.

A detail of the bottom of the wall painting with most of the surrounding (modern) plaster removed

All of this was necessary in order to carry out the somewhat daunting task of removing the painting from a frame that has done a great job of protecting it for close to 100 years. It had decidedly reached its useful lifespan though, which is why it needed to be removed. Removing the frame was also going to be the only way for me to evaluate the stability of the wall painting and its more recently applied (modern) plaster backing, and also offered the opportunity to do a more thorough examination of the mud plaster substrate.

When I decided that I was ready to try to remove the frame, I still wanted some moral support (and an extra set of hands and eyes), so I asked my co-worker, Penn Museum conservator Nina Owczarek, to come up and help me. And boy, was Nina more than ready for this-apparently she couldn’t wait to do a little destruction.

“This is why I am a conservator” Nina said as she pried off one of the frame elements with a twinkle in her eye.

After weeks of careful preparation-any guesses as to how long it took us to get the frame apart? Armed with just a screwdriver and a metal spatula, we managed to get it off with relative ease in less than 15 minutes. That frame was ready to come apart, and we didn’t need to use a saw to do it (thank goodness) which is what I had been expecting.

Here is the final result:

The wall painting lying next to its frame-bits of the paper and modern plaster from the side of the frame have fallen off to one side

And here are a couple views from the side, showing the thickness of the original mud plaster, and the plaster backing underneath, set onto a piece of plywood.

Two views of the wall painting, with bits of plaster and paper still partially adhered to one side

In the end, even though it got my heart pumping a little bit, it wasn’t really that nerve-racking after all – all of that preparation paid off! And Nina and I deemed it totally high-five worthy. I’m looking forward to working on this tomorrow, and to moving forward with this treatment.

Mystery fiber

Posted on February 23, 2013 by mollygleeson

In a recent blog post I mentioned that I am working on the painted coffin of Tawahibre, which has fibers mixed into the ground layer (gesso). In my examination prior to starting treatment, I had noted these fibers, and observed that they are present all over the coffin lid, mixed into the ground layer just below the painted surface. They are exposed in many places where there are losses-here is an image of one area where the surface of the coffin is badly damaged, revealing these fibers:

Fibers visible in the ground layer of the painted coffin lid

There are quite a lot of these fibers in some areas (as seen in the photo above), and then in others, there are very few. They are found in areas where the ground is thick and also where it is applied very thinly. They are not arranged in any particular way-they appear to have been mixed haphazardly into the ground. The fibers are light brown in color, and while most of them are very stiff, they react almost immediately to moisture, becoming very flexible when wet. I had initially assumed that these were plant fibers-possibly flax-but they always seemed a bit odd, and to be honest, these fibers remind me a little bit of sinew (animal tendon).

As I have been working on the coffin, several of these fibers “presented themselves to me” for sampling-meaning, as I’ve been working to stabilize some of the areas with these fibers, a couple became detached, allowing me to investigate them further using PLM. So far I have looked at 2 samples, and both look the same. I prepared the fibers by mounting each one on a glass slide with water. When looking at them in plane-polarized light, they look like this:

Two different fibers from the coffin ground layer viewed at 50X magnification

I didn’t really know what I was seeing-it was difficult to pick out any really distinguishable features, so I then viewed both fibers under crossed polars. This is what I saw:

Same two fibers viewed under crossed polars at 50X magnification

What the heck is that? I’ve never seen anything like this before. When I showed this to a few other people, the first reaction has been-it looks like a worm! And it totally does. This very regular banding pattern has got to be characteristic of something-I just don’t know what.

I thought I had a lead last week-I found this image in a book, showing a bundle of sisal fibers with a commonly-seen spiral element:

Sisal sample showing a characteristic spiral element. Image from “Color Atlas and Manual of Microscopy for Criminalists, Chemists, and Conservators” by Nicholas Petraco and Thomas Kubic, p. 94.

However, just last week I obtained a sisal sample from one of the Winterthur art conservation graduate students and I’m pretty sure that’s not what I have. The sisal sample looks distinctly different to me-here it is in both plane polarized light and under crossed polars:

Sisal reference viewed at 400X magnification in plane polarized light (left) and crossed polars (right). Also, note the difference in magnification between these fibers, viewed at 400X, as opposed to the coffin mystery fibers above, viewed at 50X.

For the moment, I’m stumped. But I’m continuing to investigate this and to get input from colleagues, and I’m open to suggestions/ideas! I’ll also certainly provide more information when I know more. To be continued…

Giving our falcon a little love

Posted on February 12, 2013 by mollygleeson

One of my favorite artifacts in the lab is a falcon mummy, which I described in an earlier post. While he is a fascinating object, this poor little guy hasn’t been able to be exhibited, or even handled very much, because some of his linen wrappings are quite deteriorated, brittle, and breaking apart, causing serious structural issues.

Overall shot of our falcon mummy

Recently, I worked to stabilize the linen wrappings on his feet, which were partially detached, and in some areas, barely hanging on by a few threads.

Side view of the falcon’s “feet” showing the fragile, partially detached linen wrappings

Before carrying out any treatment, I did a little bit of research and carried out some testing to determine what materials I might want to use to repair the textile. I knew that a stitched repair would not be possible, as the linen fibers are far too weak and this would likely cause further damage, so I started investigating different adhesives and support materials to use instead. As part of this process, I consulted with Nancy Love, a local conservator in private practice who specializes in textiles. Nancy recently visited me in the Artifact Lab, and among the other materials I was trying, she suggested that I experiment with nylon bobbinett, a heatset nylon net.

I did some experimentation with it, and I really liked how it behaves, both as a support fabric and as an overlay to protect fragile areas-it drapes well and can be toned easily with dyes or paint. After feeling satisfied with the results of some of my tests, I set out to repair the damaged linen over the falcon’s feet.

I started by toning the bobbinett with Golden acrylic paint. Then I backed the fabric that was dangling off the back of the foot with the toned bobbinett lightly coated with 10% methylcellulose in water. I then used the bobbinett support fabric to raise the partially detached fabric up into place, secured temporarily with pins.

After positioning the linen, I covered the entire back of the foot area with another piece of toned nylon bobbinett.

The back of the foot area with an overlay of the toned nylon bobbinett, after treatment

Finally, I tacked down the strip of linen over the top of the feet, which was also partially detached but otherwise fairly stable, using small beads of methylcellulose. Reattaching the linen over this area also hid the edge of the nylon bobbinett overlay.

View of the front of the foot wrappings, after treatment

I’m pleased with the results, and I can now breathe a sigh of relief that we’re not going to lose any more of the linen from this area. My next task will be to address the falcon’s partially detached head/neck area. Hang in there, little guy!