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.

2013 Philadelphia Science Festival Preview

Posted on March 12, 2013 by mollygleeson

Our table at the Science Festival Press Preview night, featuring our portable XRF analyzer and a Proscope. At right, Lynn demos the Proscope, magnifying a piece of linen at 50X.

Last night, Lynn Grant, Penn Museum Public Relations Director Pam Kosty, and I went to the Franklin Institute for a Press Preview for the 2013 Philadelphia Science Festival. Our museum is hosting a signature event for the Science Festival this year, entitled: “Long Live Our Treasures: The Science of Conservation and Preservation.” We have partnered with 17 other organizations for this program, which will spotlight the typically “behind the scenes” work of conservation professionals through demonstrations, exhibits and short talks. All of this will be taking place on Wednesday April 24 from 5-8pm at the museum.

At the preview last night, we got a taste (literally) of some of the other programming that will be taking place at the Science Festival, including a chance to try fruit from a cacao pod, thanks to Mars Chocolate Research Fellow Ed Seguine (who tastes chocolate for a living – how envious am I?) and a sample of chocolate bourbon habanero ice cream made with liquid nitrogen (so delicious and creamy!) made by the evening’s host, the Franklin Institute.

A partially opened cacao pod (left) and the liquid nitrogen-prepared ice cream being served (right)

At our event for the Science Festival on April 24, we are looking forward to sharing our work in the Artifact Lab – we will be open till 8pm that evening and visitors will have a chance to use our Proscopes (like the one in the image above) and learn about how we are conserving mummies and other Egyptian materials. This event also, appropriately, coincides with National Preservation Week. We’re excited to be hosting this program and highlighting the field of conservation, and we hope that those of you in the Philly area can join us for this!

A technical study of a child sarcophagus

Posted on March 6, 2013 by mollygleeson

Casey analyzing the surface of the child sarcophagus using a portable XRF analyzer. Photo by Vanessa Muros

I have a special treat for our readers today – I recently had an interesting discussion with Casey Mallinckrodt, a current graduate student in the UCLA/Getty Program in the Conservation of Archaeological and Ethnographic Materials (which is also my alma mater!).

As part of her graduate studies, Casey has been working on a rare example of an Egyptian child sarcophagus, and instead of recounting the conversation for everyone, I asked her if she’d be willing to answer a few questions for our blog. Read on to hear more about Casey and this fascinating project.

1. First, tell our readers a little more about yourself.

I am a second year MA student in the UCLA/Getty Program in the Conservation of Archaeological and Ethnographic Materials. This is a career shift for me having received an MFA in sculpture in 1988 and having had a career in fine arts and education. I did pre-program internships in conservation at the Museum of Modern Art and the American Museum of Natural History in New York before applying to this program.

I am working on this project with Dr. David A. Scott and Prof. Ellen Pearlstein, both of whom are faculty in our program. Marie Svoboda, a conservator of antiquities at the Getty Villa, and Dr. Kara Cooney, an Egyptologist at UCLA are advisors.

A view of the upper half of the sarcophagus

2. Tell us more about this child sarcophagus that you’re working on and why it is so unusual (that’s assuming that it is!!)

The sarcophagus (or coffin) lid is on loan for this project from the San Diego Museum of Man. It was given to the museum in 2001 and it dates to the Ptolemaic period, 305 – 30 BCE although the exact date of this object is not known. It is unusual because sarcophagi were costly and rarely made for children. This is supposed to be one of only seven from this period known to exist. It seems to have been for a girl, and scholars I consulted suggest she may have been a child wife, which would justify the expense. Many people have asked about the mummy and the base of the coffin but these are unknowns.

It is made of a carved out section of a tree trunk with pieces added to create the chest, face and foot. Wood dowels were used to secure the pieces in place. The exterior is completely covered with a polychrome layer made up of a base of a brown granular paste, then a white “gesso” layer and the paint applied onto that. The interior is unpainted.

A side view of the sarcophagus in the UCLA/Getty labs

3. What is your ultimate goal for this project?

The project is a technical analysis of the structure and materials, and development of a treatment plan. The treatment goal is to stabilize the structure and fragile paint layer, and reduce or removal modern fills that may be damaging the original materials. If the museum approves I will carry out treatment in selective areas to establish a protocol so the museum can continue the work after the coffin returns to San Diego in June.

4. Since I get asked this question almost every day, I’m going to turn around and ask you – what is the most interesting and/or unexpected thing that you’ve found so far in your work on the sarcophagus?

It is a fascinating project in so many ways, but two things come to mind. One involves the manufacture, and the other a mysterious surface condition.

The ancient Egyptians frequently reused parts of coffins and I have found evidence of reuse here. X-rays reveal empty dowel holes that indicate changes in the structure, and there are modern metal screws holding the foot block in place.

X-radiographs of the head (left) and foot (right) of the sarcophagus. Note the modern screws holding the foot together.

Scholars I have consulted find the carving of the face more consistent with earlier periods. I am examining the types of wood and indications of changes in the construction, and analyzing the pigments, gesso, fill materials, and coatings to identify differences that might point to different sources for the different parts.

The most unexpected development was the emergence of small waxy exudates on the lower front of the “torso”. I am doing chemical tests on samples, and FTIR (Fourier transform infrared spectroscopy) is being carried out by Getty Conservation Institute Scientist Herant Khanjian to identify the substance and determine whether it poses a threat to the original materials. This is probably the result of a coating or consolidant that was put on the object, but there is no record of its treatment before SDMM acquired it.

Thanks Casey! This is a terrific project, and a great example of how conservation is often a very collaborative process, involving conservators, scientists, archaeologists, and other specialists.

I will be keeping up with Casey as her work progresses. For more information on the UCLA/Getty Conservation Program and other student projects, follow the links I’ve included in the text above.

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 update

Posted on February 23, 2013 by mollygleeson

A quick update on our mystery fiber (see my previous post for details):

Today I decided to do a chemical spot-test to see if I could determine if the fiber was cellulose or protein-based. Chemical spot tests are inexpensive, generally simple procedures that conservators may use to characterize materials on artifacts. These spot tests are often carried out on small samples removed from artifacts using chemical reagents. In the case of my mystery fiber, I cut a small piece off of one of the fiber samples I previously examined under the microscope-this small piece was enough for a spot test, and there was no need to remove more material from the coffin in order to do this.

The first test I chose to carry out was the Biuret test for protein (according to instructions in Material Characterization Tests for Objects of Art and Archaeology), using copper(II) sulfate. After placing a drop of copper (II) sulfate solution on the sample, I waited for a few minutes, then soaked up the excess solution and added a drop of sodium hydroxide solution to the sample. It immediately turned purple (see below), which indicates the presence of protein (and just in case it’s not clear on your screen, believe me, it is purple!).

Magnified image of the sample used for the protein spot test. The purple hue indicates a positive reaction for presence of protein. 50X magnification

What this means is still unclear, but it’s another clue. It is possible that my earlier comparison of this fiber to sinew was not a bad suggestion! But it’s also possible that this fiber was coated in a protein-based glue before it was incorporated into the gesso (or something like this).

This calls for further investigation!

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…

Art conservation students visit the Artifact Lab

Posted on February 21, 2013 by mollygleeson

Last Saturday, I was pleased to give a special tour of the Artifact Lab to a group of students from the University of Delaware.

Group photo in the Artifact Lab

This group was made up of graduate students in the Winterthur/University of Delaware Graduate Program in Conservation (WUDPAC), a pre-program intern currently working in at Winterthur, and undergraduates majoring in art conservation at the University of Delaware.

Several students gathered for our open window session

They arrived during our open window session, and then we continued the tour afterward, which gave me the opportunity to present some of my ongoing work and experiences working in an open lab. While I speak about my work every day, discussing my work with students who are learning some of the latest treatment techniques and analytical methods, and who have this information fresh in their minds, was incredibly useful for me. Since their visit, I have received some generous offers of sharing material samples and articles. I know that visiting the Artifact Lab must have been a treat for them, but I think it was equally rewarding for me!

A step a- “head”: improving storage for our mummified heads

Posted on February 16, 2013 by mollygleeson

As I mentioned previously, we have several mummified heads in the Artifact Lab. Luckily, all of them are stable and do not require much in the way of conservation treatment – instead we have focused on examination, documentation, and some light surface cleaning, and in one case, the removal of an old exhibit armature.

We have a lot of things going on at the moment, so thankfully, I’ve gotten some help with this work. A couple weeks ago we had a group of 5 undergraduate art conservation students from the University of Delaware in the lab – they spent the month of January interning in our department on a project focused on documenting and cleaning a group of Arctic boats in storage.

Ellen Nigro and Rebecca Selig condition reporting a kayak

They wrapped up that project a day early, and so on the last day of their internship, they got to work on something totally different – and several of them elected to help condition report one of the heads.

Rebecca Cruz, Emily Cummins, and David Brickhouse examining a mummified head

After fully documenting the heads and carrying out any necessary treatment, our main goal is to construct new storage mounts for these remains. Our Egyptian storage areas are fairly packed with artifacts, and because of this, many things are stored in a way that makes them hard to access or see without a lot of handling.

An example of artifacts wrapped nicely in acid-free tissue in a drawer – unfortunately, there is a lot of handling required to see these objects

New storage supports will improve access and provide better protection for these remains. Our plan is to make handling trays for the heads, which can then be housed within custom-made boxes.

An example of a handling tray, made using acid-free corrugated board and Volara polyethylene foam

I’m getting some help with this as well – Artifact Lab intern Melissa Miller has been working on the first tray and box.

Melissa working on creating a custom-made box for one of the heads

We will be sure to post photos once we’ve completed them!