High tech/low tech

We often talk about how we try to take advantage of new technologies whenever possible as part of the conservation examination and treatment of objects. It’s those new technologies that help us continue to learn and do more with objects that we have had for 100+ years. For example, even though x-ray radiography has been around since the late 19th century (see this image of the first radiograph ever captured in 1895) there have been major advances since then, including the development of computed tomography (CT-scanning) and digital radiography, so we frequently re-image objects that were x-rayed in the past to capture even more details (see this blogpost to see the recent radiographs we captured of our mummy Nespekashuti).

There are also many other new technologies that we use on a regular basis (at least in some instances), including our portable x-ray fluorescence analyzer (pXRF), our Mini-Crimescope, our Lynton laser cleaner, just to name a few.

Ron Almagno, a Forensic Instruments Specialist, shows our department some of the features of our Mini-Crimescope.

Ron Almagno, a Forensic Instruments Specialist, shows our department some of the features of our Mini-Crimescope.

But there are just as many, if not more, instances when the low-tech method or solution makes the most sense and gives the best, or just as satisfactory, results. I can provide many examples of this, but the latest low-tech approach that I’m taking in the Artifact Lab is figuring out how to examine and work on Nespekashuti and his coffin base.

I decided to tackle the treatment of Nespekashuti’s coffin before dealing with his remains. After working on all of the areas I could reach while it was sitting on a table, I realized that I needed access to the underside of the coffin. When I’ve worked on the back of other coffins, I first work on the exposed side and then flip the coffin over and work on the back (see a previous blogpost (including video footage!) Flippin’ coffins). The only problem with Nespekashuti and his coffin is that he is still inside, and I’m not ready to take him out yet (or ever…more on what I’m thinking about how to best preserve his remains in a future post). So, the best way to get at the underside was to put the coffin up on sawhorses, padded with Volara polyethylene foam.

Nespekashuti in his coffin up on sawhorses in the Artifact Lab.

Nespekashuti in his coffin up on sawhorses in the Artifact Lab.

This immediately allowed me to see some of the painted decoration on the underside, which I had never seen before:

Detail of the back of Nespekashuti's coffin

Detail of the back of Nespekashuti’s coffin

I’ll work on the areas that are exposed and then I can move the sawhorses around to document and work on the areas that are obscured at the moment.

I’ve started to stabilize the flaking gesso, lifting linen, and paint in the areas I can access, and I’m securing these areas while they dry with plastic wrap, silicone-release Mylar, pieces of Volara foam, archival board, and weights.

Detail of an area being secured with plastic wrap, foam, archival board, and weights.

Detail of an area being secured with plastic wrap, foam, archival board, and weights.

So there is nothing high-tech about what I’m doing with Nespekashuti in the lab at the moment, BUT the treatment will eventually allow us to do more high-tech things with him, like CT-scanning, multispectral imaging…and anything else that we can gain access to that may help us learn more about him.

 

A closer look at our stola coffin lid

In my last post about this late 21st/early 22nd stola coffin lid, I referred to it as eye candy.

Overall before treatment image of the stola coffin lid, L-55-16B

Overall before treatment image of the stola coffin lid, L-55-16B.

This coffin is beautiful, and we could discuss how nice it is to look at all day. But in this post, I’m going to focus on some of the more subtle, somewhat less-attractive (but perhaps even more interesting) features that I’ve discovered about this coffin lid as I’ve begun to work on it. In fact, on Friday I spent awhile discussing some of these details with a group of conservators and interns from the Philadelphia Museum of Art (PMA). As I mentioned in my last post, although this coffin has been on long-term loan to us since the 1930s, it still technically belongs to the PMA, so I am carrying out my treatment in close consultation with one of their objects conservators.

Penn Museum conservator Alexis North (far right) discusses a cat mummy with the PMA conservators and interns.

Penn Museum conservator Alexis North (far right) discusses a cat mummy with the PMA conservators and interns.

I always appreciate the opportunity for professional exchange, and I was happy to be able to discuss my plan, including materials and approaches with them. This discussion energized me to get started with the treatment, and that is exactly what I did, almost as soon as they left.

One thing that I noticed in my initial examination is that this coffin lid has been worked on before. There are residues of old adhesives in areas, including an adhesive mixed with a sawdust-like material, especially around the foot of the coffin.

Adhesive residues on an area of exposed wood.

Adhesive residues on an area of exposed wood near the foot.

I have seen these same types of repairs on at least one other coffin in our collection, and while there is no documentation of them, I am suspicious that this treatment was carried out in our museum soon after we acquired this coffin, but long before our conservation lab was established 49 years ago.

The foot of the coffin has another type of repair as well – there are 2 brackets that are held on with screws on the underside of the foot, apparently to secure some of the wood components. This whole area moves when handled, so the brackets and screws will have to come off so that I can better assess what is going on.

Detail of the foot of the coffin, showing the brackets used in an old repair.

Detail of the foot of the coffin, showing the brackets used in an old repair.

There is some very powdery material associated with areas of damage, especially on the face, which appears to be partially due to deterioration of the mud plaster, but also may be due to insect activity. I’ll have to investigate this further over the course of the treatment.

Detail of the powdery material near the left eye.

Detail of the powdery material near the left eye.

And then there are some materials included in the mud plaster, including some course linen threads and even a leaf, which I am documenting as I work to clean the surface.

Detail of a detached piece of mud plaster with linen thread inclusions.

Detail of a detached piece of mud plaster with coarse linen thread inclusions.

L-55-16B_detail7

Detail of an area of damage, which exposes a small corner of what appears to be a leaf caught in the mud plaster.

The next time I post images of this coffin lid, it should be a lot cleaner, as I plan to complete the initial surface cleaning within the next week. More soon about this, and other observations and developments in the treatment.

 

Treating Nespekashuti’s coffin

Many of you may be wondering about Nespekashuti, our New Kingdom mummy whose remains are quite a jumble under his wrappings. As you can imagine, Nespekashuti is presenting some interesting conservation challenges for us. So far I have focused on surface cleaning and trying to understand the extent to which his linen wrappings are damaged. I decided that before I can deal with stabilizing Nespekashuti any further (and making the decisions necessary to do this), I need to address the damage to his coffin.

Overall view of the proper left side of Nespekashuti's coffin (before treatment)

Overall view of the proper left side of Nespekashuti’s coffin (before treatment)

Nespekashuti’s coffin is quite interesting. I’ve only been able to examine the lower half (which he is contained in) so far. It is made of several pieces of wood doweled together, followed by coating with gesso in areas, then the exterior surface is entirely covered with a single layer of linen, which was coated with gesso and painted, and then finally varnished, likely with pistacia resin. Overall, the painted surface of the coffin is in great condition. But there are some structural concerns, including breaks in the wood, separation and movement between different pieces of wood, and separation of the linen, gesso, and paint from the wood substrate.

Detail of the exterior foot of the coffin, showing separation of the linen, plaster, and paint from the wood.

Detail of the exterior foot of the coffin, showing separation of the linen, plaster, and paint from the wood.

Detail of damage on the proper left side of the coffin.

Detail of damage on the proper left side of the coffin.

I’m starting out my treatment by readhering areas where the linen is lifting away from the wood and plaster below. To repair these areas, I’m using a tried-and-true combination of methyl cellulose, methyl cellulose bulked with glass microballoons, and Japanese tissue paper.

Treatment in progress - I'm using clamps to hold areas in place while the adhesive dries.

Treatment in progress – I’m using clamps to hold areas in place while the adhesive dries.

During treatment - image detail showing the same area at the foot of the coffin (seen before treatment in the second image in this post).

During treatment – image detail showing the same area at the foot of the coffin (seen before treatment in the second image in this post).

This is just the beginning! Once I finish working on the areas I can access, I’ll have to move the coffin to a support that allows me to access the underside/back, so that I can better evaluate and treat those areas as well.

Exploring the painted surface of three coffin fragments

Last week, I wrote about x-raying the fragments of a painted wooden coffin, as part of the conservation treatment. The radiographs helped us see what is under the painted surface. We then turned to the painted surface itself. Through cleaning, we revealed how beautiful and well-preserved the decoration is. I described the cleaning process (and linked to a short video showing the process!) in a previous post.

E12617beforeaftercleaning

E12617A-C coffin fragments before (left) and after (right) cleaning

While it was impossible to see the full range of colors on the boards before cleaning, after cleaning we could see that there were several different colors used to decorate the surface, including two different yellows, red, green, black, and paint that appears black but where it is abraded/damaged looks blue. After much experience working on ancient Egyptian painted wooden artifacts, I knew enough to suspect that some of the paint that appears black is actually Egyptian blue.

It appears that there is a lot of black paint here, but not all of this paint was originally black. The yellow arrows point to black paint while the red arrows point to areas that I believe were originally blue.

It appears that there is a lot of black paint here, but not all of this paint was originally black. The yellow arrows point to black paint while the red arrows point to areas that were originally blue.

If you’ve been reading our blog, you are probably very familiar with one of our favorite photography techniques for Egyptian material, visible-induced infrared luminescence imaging. I have written about it previously, where I explain the process and the equipment we use (follow this link to the post).

Sure enough, it worked beautifully to confirm, and to allow us to see the Egyptian blue on this object:

E12617normaIRfalsecolor

Image of the coffin boards in normal light (left), Visible-induced infrared luminescence image (center), False color image (right). Click on the image to see a full-screen version.

All of the darkened/altered Egyptian blue shows up as bright white in the center image above, and the red areas in the false color image on the right help to further visualize where the blue is in relation to the rest of the painted design. Gotta love this technique!

So that’s great for determining the presence and location of Egyptian blue. But what about some of the other colors? I was particularly curious about the two different yellows and the green. In the case of the yellows, are they two different pigments? And as for the green, which pigment(s) were used to produce this color? Without (for the moment – more about that later) knowing the exact time period of this object, I knew there could be at least a couple different options, including Egyptian green (or green frit), and green earth.

To gather more information about these pigments, I carried out portable x-ray fluorescence analysis (pXRF) in select areas on the boards. I collected data from the following areas, marked with colored X’s in the image below:

pXRF analysis locations, with elements detected listed in order of peak height, from large to small

pXRF analysis locations, with elements detected listed in order of relative peak height, from large to small

As you can see, I labeled the image with the findings from the pXRF analysis. It looks like the two different yellows are indeed two different pigments: the darker, more orange-yellow paint contains primarily calcium and iron, suggesting that this is an ochre, while the brighter yellow paint contains calcium, arsenic, and iron. The relatively large amount of arsenic suggests that this yellow was produced using orpiment (arsenic sulfide).

The green paint also contains arsenic, as well as calcium, copper, and iron. So it appears that the green was produced by mixing an arsenic-containing material (orpiment?) with a copper-containing pigment. Due to the lack of any visible-induced IR luminescence in the green areas, I don’t think that these areas could contain any Egyptian blue, so perhaps the green was made by mixing orpiment with Egyptian green. And as you can see, the blue paint does not contain any arsenic, but does contain calcium, copper, and iron, which we expect to find in areas painted with Egyptian blue. Further analysis will be necessary to determine exactly which pigments were used in the yellow and green areas, but we have discovered a lot using these completely non-invasive techniques!

In my next post about this object, I hope to write about the translation and interpretation, for which I’ll need to consult with the museum’s Egyptologists. In the meantime, if you’d like to learn more about green pigments on ancient Egyptian objects, and more applications of multispectral imaging on Egyptian objects, check out this really great video presentation by Kelsey Museum Conservator Carrie Roberts (originally presented at the 2014 ASOR Annual Meeting):

Green Pigments: Exploring Changing in the Egyptian Pigment Palette from the Late to Roman Periods through Multispectral Imaging and Technical Analysis

X-raying fragments of a painted wooden coffin

I recently completed the treatment of these coffin board fragments.

E12617A-C, boards from a painted wooden coffin, before treatment

E12617A-C, boards from a painted wooden coffin, before treatment

In addition to the cleaning, which I blogged about before, the treatment involved stabilization of loose and powdery gesso and paint, filling losses where needed for structural support, and x-radiography, multispectral imaging, and portable X-ray fluorescence (pXRF) analysis. It has also enabled a translation of the text. I’m going to write a few shorter posts to highlight the different components of this project, starting with the x-radiography.

During my initial examination of the boards, I could see that the boards represent just a portion of the front, head end of the coffin. The rest of this side of the coffin would have continued much further to the left, but at some point these pieces were cut down and finished off on the left side to a smooth edge. This is most evident when you look at the hieroglyphic text, which obviously should continue to the left.

I could see that these 3 boards were originally joined with wooden dowels, because there are wooden dowels protruding from the join edges. I also noted some large cracks in the painted surface of the largest (center) piece in the image above, which led me to realize that this central piece was made of more than 1 piece of wood. I turned to x-radiography to get a better understanding of what is going on below the surface.

Here is a composite image showing the radiographs of the 3 boards:

E12617A-C x-ray image

E12617A-C x-ray image

The dowels joining the 3 pieces together are very clear in the x-ray image above. There are some darker (almost black) areas, which represent the holes that were drilled out for inserting the dowels. The denser (whiter) areas within those voids are the wooden dowels themselves. I’ve outlined these areas in green in the image below.

E12617xraymapped-1The x-ray image also helps clarify how the center piece is constructed, with 3 pieces of wood, which I’ve outlined in red above. Where those 3 pieces of wood join correspond directly with the cracks observed in the painted surface on the exterior.

Also visible in the x-ray image are two small nails driven into the lower edge of the bottom board. These nails are historic additions, likely added at the time when the boards were cut down and modified, although their purpose is unknown.

In my next post, I’ll focus on what cleaning, pXRF, and multispectral imaging has revealed about the painted surface, and I’ll include some after-treatment images.

 

We love ugly objects too!

Last week, I posted some photos of a beautiful stola coffin lid that I’m working on at the moment, and I mentioned that this lid might be my new favorite object. I now somehow feel a need to post images of some objects that aren’t necessarily as pretty, but I want to assure you that we’ll give them just as much lovin’ here in the conservation lab.

A Nubian jar, ca. 100 BCE-300 CE and ivory horn protectors from Kerma (Sudan), ca. 1650-1550 BC

A Nubian jar, ca. 100 BCE-300 CE and ivory horn protectors, Kerma (Sudan), ca. 1650-1550 BCE

A cat mummy head, unwrapped, Thebes, ca. 664-332 BCE

Cat mummy head, unwrapped, Thebes,                 ca. 664-332 BCE

Sections of a beaded mummy shroud covered in wax

Sections of a beaded mummy shroud covered in wax, Egypt, exact site and date unknown

I also feel the need to mention that I don’t just love pretty objects. My most favorite “object” that I’ve worked on here in this lab in not an object at all, but a mummy – our Predynastic mummy Bruce, and I don’t think anyone would call him pretty. But please don’t take that the wrong way (I don’t think he would be offended either). My interest in him goes way beyond his looks.

I promise to post photos of what the objects in the images above look like before they leave the conservation lab. Conservator Alexis North will be working on these pieces (along with some help from our interns) in the upcoming weeks.

This post was inspired in part by a great blogpost on the Kelsey Museum of Archaeology’s blog, “Ugly Object of the Month“. Enjoy!

 

Observations of a stola coffin lid

As if there is not enough up here (see our recent post about the Egyptian storage move and associated conservation work), this week we brought another quite large object into the lab, and it might be my new favorite object up here.

The lid of our yellow stola coffin

The lid of our* yellow stola coffin

This is the lid that belongs to the late 21st/22nd Dynasty yellow coffin base which we recently treated here in the Artifact Lab. Due to its previous location in storage, I hadn’t been able to take a close look at it until this week. Now that I’ve gotten to spend a few days with the lid, I’ll tell you that it’s total eye candy. If you were impressed by the painted decoration on the base, the lid will give you even more to get excited about.

I only just started to examine and document the lid and I will continue to update the blog as I work on this object, so today I’m just going to mention a few things about it, and some of my favorite details so far.

First of all, you may have noticed that I referred to this as a “stola” coffin in the image caption above. The term “stola” refers to the narrow red band depicted on the coffin that encircles the neck and crosses over the chest and over the oversize collar. Both the presence of the stola and the oversize collar have been recognized as distinctive of the late 21st/early 22nd Dynasty (see other examples and explanations here and here, and special thanks to Dr. Kara Cooney at UCLA for information as well).

The figure depicted on this coffin used to have a beard, which is now missing, but there is a hole in the chin indicating that it was once there.

Detail of the hole in the chin

Detail of the hole in the chin

The arms are depicted as being crossed over the chest and the hands are made of separate pieces of wood. The hands on this coffin are clenched and I have read that this is reserved for male coffins while females are depicted with hands open and lying on their chests. I’m assuming the fisted hands mean that this coffin belonged to a man, but I’ll have to check with our Egyptologists to confirm, since I cannot translate any of the text myself. I also really like the fact that the thumbnails are painted in:

Detail of the left hand

Detail of the left hand and thumb

What else can I say about it? Well, it is beautifully painted and also varnished just like the base with a yellow-colored pistacia resin. This pistacia resin causes many of the areas painted blue to appear green:

Much of the blue lines on the wig appear green, but in areas where there is no varnish, you can see the blue color of the paint.

Many of the lines on the wig appear green, but in areas where there is no varnish you can see the blue color of the paint.

There is a thick layer of dust on the surface of the coffin, but I can tell it’s going to clean up well. Check out the embossed details in this raking light image, which were built up with gesso:

Detail of the embossed designs on the central part of the lid

Detail of the embossed designs on the central part of the lid

This is going to be a fun object to work on! I’m looking forward to getting started with the treatment.

* I should clarify that this coffin technically belongs to the Philadelphia Museum of Art (PMA) but has been on long-term loan to us for nearly a century. We received this coffin as part of an exchange of objects between our 2 institutions in the 1930s. I am carrying out the treatment in close consultation with the conservators at the PMA.

Wax on, wax off

In my last post, I briefly described the Egyptian storage move project currently underway. And I also promised to feature some of the objects that are in the lab as a part of this project. As conservators, we get excited by lots of things, so I really can’t post images of every single object that comes into the lab, but we will try to post as much as we can here, on Twitter, and on the museum’s Facebook page.

Earlier this week, Alexis brought a drawer of beadwork up to the lab, and this is one of the pieces she found in that drawer:

A piece of beaded fringe that recently came to the Artifact Lab for conservation/re-housing.

A piece of beaded fringe that recently came to the Artifact Lab for conservation/re-housing.

Huh. Not the prettiest object I’ve ever seen. But just wait…

Partially cleaned beadwork

Partially cleaned beadwork

Under that dark material (which is wax) the beadwork is beautiful! We actually see a lot of beadwork in our collection that has been coated with wax, which has now discolored to a dark brown, completely obscuring the colors of the beads. Coating beads with wax was a method used by archaeologists to remove beadwork from mummies during excavation, in order to maintain the correct arrangement of the beads, since the original linen threads were usually mostly deteriorated. In the case of this beadwork, shown above, it was not only waxed, but affixed to a piece of cardboard. Alexis is currently cleaning the wax off the beads and she will eventually re-house this piece for safe transport to the off-site storage location.

Another cool detail – she found this, written on the back of the cardboard:

HapimenbeadsIt says: “E16220B. Bead fringe of Hapi-men, Pl. LXXIX Abydos. From mummy buried with his dog.” This small piece of beadwork belongs to our mummy Hapi-Men, who is currently on exhibit with his dog! Hapi-Men and Hapi-puppy were excavated by Sir Flinders Petrie from Abydos in 1902. You can read more about Hapi-Men and some of our research about him here and here.

 

Treasures from Egyptian storage

If you have visited the Artifact Lab in the last couple weeks, you may have noticed that we have a few more objects out than usual, and often, an additional conservator working in here.

A few objects that were brought to the Artifact Lab recently for conservation treatment before they are moved off-site.

A few objects (stone, cartonnage, ceramics) that were brought to the Artifact Lab recently for conservation treatment before they are moved off-site.

The new objects were recently brought up from Egyptian storage by conservator Alexis North, who was previously here as a graduate intern, and now is working as the new Project Conservator for the inventory and move of our Egyptian collections to an off-site facility.

Due to construction that will be happening at the Hospital of the University of Pennsylvania (HUP), which is adjacent to the museum, certain storerooms and galleries will be affected and as a result, the entire Egyptian collection in storage (with some exceptions) must be moved off-site for the duration of the project. This move requires a new inventory of the collection and also that everything be examined and stabilized, through conservation treatment and/or packing solutions, which will benefit the collection greatly. In addition, emptying the Egyptian storerooms will allow us to carry out a much-needed renovation of these areas, so that when the collections return, they will be housed in a much better protective environment.

We will try to feature some of the more interesting objects that come up to the lab as a part of this project on the blog, but if you do have a chance to stop by the Artifact lab this summer, you’ll be in for a treat, I assure you, because we will be working on some pretty amazing things.

This faience beaded collar is just one of the beautiful beaded objects that came into the lab recently as part of the move project.

This faience beaded collar is just one of the beautiful beaded objects that came into the lab recently as part of the move project.

 

The treatment of (half of) a yellow coffin

This week, we finally finished the treatment of the lower half of our 21st/early 22nd Dynasty yellow coffin.

A view of the interior of the coffin before (left) and after (right) conservation treatment.

A view of the interior of the coffin before (left) and after (right) conservation treatment.

The treatment mostly involved cleaning the interior surfaces to remove dust using a soft brush and HEPA-filtered vacuum, and cosmetic sponges. Here’s another view to give you a better sense of just how much grime had accumulated in the interior of the coffin:

A detail of the head of the interior of the coffin before (left) and after (right) conservation treatment.

A detail of the head of the interior of the coffin before (left) and after (right) conservation treatment.

There was also a fair amount of flaking and lifting paint, which needed to be stabilized. We used 1-2% methylcellulose in 50:50 water/ethanol to consolidate flaking paint, and Japanese tissue paper and 5% methylcellulose to fill gaps.

In the course of the treatment, I have also continued to research the significance of the holes drilled into the bottom of the coffin, which can clearly be seen in the overall images at the top of this post, but here is another look:

An overall shot of the coffin bottom, with a detail of 4 of the holes below.

An overall shot of the coffin bottom, with a detail of 4 of the holes.

I’m anxious to start working on the lid of this coffin, which will inevitably provide more information about this object and it’s history. We should be able to bring the lid from storage up to the lab sometime this summer, and I’ll post images of it as soon as it arrives. In the meantime, I have enjoyed researching these types of coffins and finding images of similar ones in other collections (like this one at the Petrie Museum, this one at the Houston Museum of Natural Science, and this “remuddled” coffin at Stanford University) which is helping me gain a better understanding of these coffins and the contexts in which they were made.