Slowly, but surely

Posted on June 5, 2013 by mollygleeson

Sometimes when working on a large, complex project, it can be hard to see progress – once certain areas are addressed/stabilized I just start focusing on all of the other problems. In these cases, I find it really helpful to write about the work, to go through the photos I’ve taken so far, and to reflect on how far we’ve come. One of the more complex treatments we’re working on in the Artifact Lab is Tawahibre’s coffin.

The last time you saw Tawahibre on the blog, she was all tied up, Lilliputian-style.

Since that last post, we actually have made quite a bit of progress, and have started realigning and filling areas where the gesso and smaller wood components have cracked and separated from the wood ground below.

One very precarious area has been a large section on the lower proper left side of the coffin – when the coffin came into the lab for treatment, this section was only just barely attached along the top, with the help of two wooden dowels as well. In addition to being just about ready to detach, this section was also very distorted and misaligned, with areas of the painted surface overlapping and abrading each other.

Before treatment detail of this large partially detached section. It was just barely attached along the top (indicated by red arrows) and by 2 wooden dowels (circled in green).

Here is a view of this section, before treatment, from above (the red arrows are just pointing out the area that I’m talking about, for clarity).

After working to humidify and realign this area as much as possible, I prepared it for filling and stabilizing by lining the wood support below and the inside surface of the detached section as possible with Japanese tissue paper, adhered with methyl cellulose adhesive. The Japanese tissue paper will serve to make these fills more easily reversible in the future.

Preparing this section for stabilization and filling. The red arrows are indicating the Japanese tissue paper used to line the inner surfaces of the coffin before filling.

To secure this section to the rest of the coffin, I applied a fill mixture between the large partially detached section and the wood support below. The fill mixture was made using 5% methyl cellulose adhesive in 1:1 water/ethanol bulked with a 1:1 ratio of alpha cellulose and 3M glass microballoons. The alpha cellulose and microballoons were chosen to create a lightweight, relatively dry, and easily moldable fill – they also make this mixture a bright white color. After applying the fill material, this section was again bound with the twill tape and ethafoam blocks to hold everything together while the fill dried.

Detail of this section after filling.

And here is a detail showing this section from above – I think it makes a nice comparison with the before treatment shot from a similar angle, above.

So far this has been a successful course of treatment and we have filled several areas on the coffin. Our current goal is to get the lid stabilized enough so that we can separate it from the base, so that we can continue to work on both sections with better access to some of the very unstable, fragile areas.

Special thanks to my conservation colleagues for their help with brainstorming, problem-solving, and carrying out this treatment!

The New Guy

Posted on May 29, 2013 by artifactlab

by Lynn Grant

Molly Gleeson, the Project Conservator for In the Artifact Lab has been very busy over the last nine months, conserving lots of Egyptian artifacts and she’s finished treatments on a human mummy, an animal mummy and has done a lot of work on PUM I. So, as these projects finish up, it’s time to start some new ones – there’s never any shortage of projects for the Museum conservators. Earlier this month, we brought another of our human mummies out of storage and into the Artifact Lab. And what a mummy he is:

E 16229, a Predynastic mummy.

Not what you were expecting, right? No stiff upright form tightly wrapped in bandages. That’s because this is a very early mummy, probably dating to “4000-3600 BCE (or from the Badarian Period to Naqada IIB to use Egyptological time periods”, to quote Dr. Jane Hill, an Assistant Professor at Rowan University, who’s been studying this mummy. Dr. Hill will be presenting some of her initial findings at a mini seminar hosted by ARCE-PA (American Research Center in Egypt – Pennsylvania Chapter) and held at Penn Museum this Saturday, June 1st, open to the public.

Because Molly is going to be away at a conference this week, I’ve begun familiarizing myself with this ‘new’ mummy so I can talk about him to the seminar attendees and our other visitors. When I say ‘new’, he’s only new to the Artifact Lab. Not only is he at least 5600 years old, he’s been in our collections since 1898. He was donated to the Museum by Ethelbert Watts, a prominent Philadelphian who was serving as an Assistant American Consul in Cairo. His history in our collections is a little unclear: we know he was x-radiographed in 1932 and we have this undated early photograph from the Archives. Since this image comes from a glass plate negative, it could date anytime between 1898 and the early 1930s, when the Museum finally switched to film based photography.

An early photograph of the mummy from a glass plate negative

We think he may have been on exhibition some time in the past but we haven’t tracked down those records yet. For at least the past few decades, he languished in a box in the Egyptian storerooms until Dr. Hill and Dr. Joe Wegner ‘excavated’ the box in 2011. Since then he’s been the subject of quite a lot of interest – Dr. Hill and her Rowan colleague Dr. Maria Rosado have been examining samples of materials associated with the mummy and sent samples for AMS/C14 dating.

Cool stuff about this mummy: he was buried in the flexed or contracted position, like many Predynastic mummies but he was also buried inside an animal skin bag, which had the animal’s hair left on the inside. He has a small, finely woven basket by his side and an animal skin cap covered by a basketry framework on his head.

Details of some of the items buried with the mummy

Clearly, this guy has a lot to tell us and we’ll keep you posted on what’s up with Bruce (yes, Bruce – it gets hard to refer to the mummies by their accession number and so many get nicknames. This guy has been Bruce to us pretty much since he came out of his box. No disrespect meant; he’s a fascinating individual and I look forward to getting to know him better).

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!

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!

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.

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!

A sticky issue: choosing a consolidant for our painted coffin

Posted on February 9, 2013 by mollygleeson

In a previous post, I described some of the issues we’re facing in the treatment of our painted coffin of Tawahibre.

The top of the coffin before treatment – note the large losses and areas where the paint and gesso are just barely hanging on by a (plant fiber) thread

We’ve managed to clean much of the painted surface, but there are many areas of the paint and gesso that are so fragile, you get the feeling that a deep exhale – not to mention a sneeze – would send fragments flying. (And when I say gesso, I’m referring to the calcium carbonate preparatory layer/ground, which has plant fiber inclusions, that I’d like to investigate further).

Such areas require consolidation. We use this word, consolidation, a lot in conservation, and many of our treatments involve this process. Consolidation is essentially the reunification/reinforcement of a weak or powdery substance through the application of a material that we refer to as a consolidant. Consolidants often consist of dilute adhesive solutions, and they may be applied directly to artifacts with a brush or syringe, by spraying onto the surface, and in some instances, it may be appropriate to immerse an artifact in a consolidant solution. Ideally, a good consolidant must be stable (good aging properties), reversible (can be removed if necessary), and should not change the appearance of the artifact.

We have mixed up a variety of consolidant solutions to have on hand in the Artifact Lab – here are a few, along with some brushes, a plastic pipette, and syringes

Choosing an appropriate consolidant requires testing ahead of time. To start, it is important to test a variety of solvents (such as water, acetone, ethanol) – knowing which solvents can be used safely on a particular artifact will likely narrow down the range of adhesives that can be used (due to the fact that many adhesives are only soluble in a select number of solvents). In the case of our painted coffin, this involved testing all of the colors of the painted surface as well as the gesso substrate. Testing was carried out by rolling a swab dampened with each solvent over a discreet area and then observing the area for changes.

Solvent testing on an area of blue paint

After carrying out these tests, I did some research into what other conservators have used successfully for similar treatments on similar artifacts. In our field, we are fortunate to have a good body of published literature, and there is increasingly more information that can be found on the web as well. The sources I referred to included articles in the Journal of the American Institute for Conservation (JAIC), and a variety of books that have been published on the subject of conservation of Egyptian collections. Websites/blogs that I have found really useful include Inside the Conservator’s Art: A behind-the-scenes look at conserving Egyptian artifacts at the Phoebe A. Hearst Museum of Anthropology, conservator’s entries on the Brooklyn Museum blog, and the British Museum’s online collections database, which has many records with detailed conservation treatment information. There are actually lots of great blogs and websites out there, and I am grateful to my colleagues for actively sharing information in this way.

After this work, I selected several consolidants, and conducted another round of testing. During my testing I discovered that water was the key to getting the paint and the gesso to relax. Unfortunately, the painted surface is sensitive to water, but I found that a 50:50 mixture of water and ethanol is acceptable for use, especially when applied in a solution behind the lifting paint. In the end, we’ve chosen to consolidate the very fragile paint with a solution of methyl cellulose (a water-soluble cellulose ether) in a 50:50 water/ethanol mixture. To re-adhere larger flakes and chunks of gesso, we are experimenting using higher concentrations of methyl cellulose alone, and in combination with other adhesives, including Lascaux, a water-based acrylic resin.

An area near the foot of the coffin, before (left) and after (right) readhering detached gesso and consolidating paint

As I’ve stated before, this will be an ongoing project in the Artifact Lab – we will continue to report on our treatment progress, and any interesting discoveries made along the way (which is inevitable!).

Don’t just DO SOMETHING, SIT THERE!

Posted on February 3, 2013 by artifactlab

Artifact Lab Conservator Molly Gleeson, just sitting there (with laptop)

by Lynn Grant
Last month, Artifact Lab Conservator Molly Gleeson was talking about her experiences being the public face (and hands, and body) of Conservation at the Penn Museum to PACA, a group of Philadelphia Area conservators. She said that one of the occasionally difficult things about work in the ‘fishbowl’ is that visitors expect to see her “doing something” (ie., interacting directly with the mummies or other artifacts in the lab) and she worries about disappointing them when she’s just sitting at the computer or thinking quietly. I’ve noticed the same thing on my stints in the Artifact Lab (although Molly is the Main Attraction, the other Penn Museum conservators all spend time in the lab when Molly’s off).

Assistant Conservator Nina Owczarek, hard at work on the Artifact Lab computer, as seen through the glass enclosure.

But In the Artifact Lab: Conserving Egyptian Mummies isn’t meant as performance art; we want to give our visitors a real look at how conservation happens and that includes the fact that we don’t spend 100% of our time actually laying hands on ancient artifacts. Before a conservator does touch any object she’s working on, she’ll spend a lot of time:
• Examining the object carefully to see how is was made, how it was used, what’s happened to it over time, what needs fixing and (as importantly) what doesn’t.
• Writing up her findings. Conservators document everything we see, think, or do with regards to an object. This is essential for various reasons: other researchers may be interested in our observations; if the treatment doesn’t go as planned, knowing what was done will make it possible to undo; if the treatment is a success, knowing what was done makes it possible to apply the same knowledge to other objects. I often find that this process really helps clarify treatment issues in my own mind.
• Researching the artifact’s past and conservation research and treatments on other, similar artifacts. If you look at the books, blue binders in the seating corner of the Artifact Lab space or at some of these sites shown on the right sidebar, you’ll see examples of the kinds of resources we use every day. The Internet is a wonderful tool, as well. There are many online resources for conservators, especially a series of discussion groups where conservators all over the world pool their information about materials, treatment options, experience, etc.

And the ‘sitting time’ doesn’t end there. With a whole host of options for treatment at her fingertips, the conservators needs to spend time just thinking through all the possible results and repercussions of her active treatments. Many of the treatments carried out by conservators are not that difficult or complex (rolling a cotton swab across a surface isn’t rocket science) but the decision-making process behind choosing the treatment is why we need to spend years preparing to get into conservation training, years in that training, and continuing to learn every day of our working lives.

Conservators Julie Lawson (left) and Nina Owczarek, with intern Naomi Shohami (foreground) consulting over a laptop in the Artifact Lab.

So
• if you see the Artifact Lab conservator at the computer, she is probably still doing conservation. She could be: documenting her work; consulting other experts; researching web resources; writing a blog post(!); or even answering a question on our blog. Got a question? Post it here.
• If you see her talking to someone, she is probably still doing conservation. She could be: seeking advice or information from a colleague; teaching an intern; communicating a cool new finding; or asking them to contribute a blog post.
• If you see her just sitting or standing looking into thin air, she is probably still doing conservation. She could be: thinking about treatment options; deciding to consult a resource; considering the results of a recent treatment; or planning a blog post.

Of course, she could also be checking her Facebook page; calling a friend; making plans for lunch; or even just taking a rest because conservators are real people too and, even in the Artifact Lab, no-one is ‘on’ 100% of the time!