Many new faces in the lab…

by Williams Project Conservator Alexis North

Yesterday, I was able to make several new friends, when the American section brought these objects up to the lab, in preparation for the reinstallation of our Mexico and Central America gallery:

 These are a group of Zapotec ceramic effigy vessels from Mexico. These types of vessels are usually found in tombs, and their meaning depends on where and how they were buried. They are often found in groups, and with other associated burial materials.

Each of these effigy vessels is elaborately and uniquely decorated. Some have human faces, some are wearing masks, and some even have animal features.

These two vessels (NA6361; 29-41-707) depict humans wearing masks.

Most of these vessels are in good condition, intact or with only small losses. At least two, however, will need a little more conservation to get them ready to display. This vessel was originally covered with a white stucco coating:

Vessel 29-41-702, depicting a masked seated figure.

The stucco is now starting to lift from the surface, and any handling can cause small pieces of the stucco to fall off. It will need to be carefully stabilized before the vessel can go on display.

Detail of the headdress of 29-41-702. The red arrows show areas where the stucco is lifting off the surface of the ceramic.

And this vessel shown below has some loose fragments which will need to be rejoined. Thankfully the amazing duck bill on his face is still intact!

Before treatment photo of 31-26-1.

For (a lot) more information and other examples of these types of vessels, check out the Foundation for the Advancement of Mesoamerican Studies, Inc., and their database on Zapotec effigy vessels.

#Transformation Tuesday: New Year’s Edition

By: Céline Wachsmuth

It’s Tuesday and that means it’s time for another transformation story. This one comes from an object going into the Middle East Galleries (click here for more information on the exciting new galleries, opening this April!).

It’s hard to believe the first month of January is almost over! Many people make resolutions for the New Year, hoping to make an improvement, big or small (myself included, I have a Google doc with a list of resolutions). Most resolutions are easier said than done, including the prevalent resolution to shave a few pounds. This bowl had similar thoughts, but made losing some weight look like a piece of cake!

Bowl before treatment (left) and after treatment (right)

This bowl had been repaired in the past, but the joins needed to be taken down because the old adhesive was failing. The bowl was pretty clean when it came into the lab so it wasn’t long before I began solvent testing the adhesive in order to make a vapor chamber. The adhesive was soluble in acetone and most of the sherds separated with gentle prodding after eight days in a vapor chamber. The old fills (made of plaster), however, did not budge. This was probably due to the likelihood that they had been cast in place.

Outlines of Old Fills
Fill outlined in dark blue was dremeled out
Fills outlined in light blue were softened with deionized water and then removed

These ounces had to go! When a fill resists detachment by solvent, other, usually mechanical, methods have to be implemented. One mechanical treatment is to use a dremel, just like the one you might use at home for some smaller detailed work, to carve away the fill. This is tricky because the dremel can put the object at risk if used improperly. Once I was all set up and had been shown the proper technique, I slowly moved around the entire area of the fill.

using the dremel to remove the fill

two of the sherds sitting in a bed of glass beads while the adhesive sets

Once the large fill was removed and those ounces had been shed, it was time for some TLC. I cleaned the break edges on each sherd with acetone (for the sherds previously joined with adhesive) or deionized water (for the sherds adjacent to the old fills). All the break edges were then coated with a dilute solution of Paraloid B-72 (ethyl methacrylate methyl acrylate copolymer) and the sherds were put back together with a 50% solution of Paraloid B-72 in 1:1 acetone:ethanol. Two small areas of the bowl had some gaps that needed to be filled; one for added structural stability and one to help complete the shape. This was done using a mixture of 3M microballoons, Paraloid B-72 in 1:1 acetone:ethanol, acetone, and some dry pigment to approximately color match the fill to the bowl. The fills needed some additional color to help blend in more and they were painted with light washes of acrylics.

This bowl made losing a couple ounces look easy even though we all know how much work really has to go in to something transformative! Thankfully, it’s only the beginning of the year and there is plenty of time to make your own transformations. Just like there’s plenty of time for another transformation to happen in the labs before our next Transformation Tuesday post – stay tuned!

PS – If you’re looking for some “ancient workout tips” check out these fun suggestions

Conserving Egyptian mummies…and more

Recent visitors to the Artifact Lab may have noticed this new sign posted on one of the lab windows:

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Since we opened in fall 2012, you might have occasionally caught us working on non-Egyptian things, but if you visit us now, you will definitely see us working on things from other parts of the collection, especially artifacts that we are preparing for our new Middle East Galleries. Right now, we are focusing a lot of our efforts on treating ceramics and lithics, most from Iraq and Iran.

We have tens of thousands of ceramics and lithics in this museum’s collection, but somehow, in my over 4 years here, I have gotten away with working on only a handful.

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Conservator Tessa de Alarcon reconstructing a ceramic vessel. This is a common sight in our main lab (behind the scenes) but not so much in the Artifact Lab…until now.

So this is how, after spending over 4 years working on mummies and coffins, working on a small ceramic vessel becomes a novelty. And that is why I am going to walk you through some of the fairly routine steps of treating a ceramic, because I’ve never gotten a chance to write about it on this blog before, and honestly, I’m excited about it.

This small ceramic vessel with a simple striped pattern was excavated in 1931 in Ur, which is a site in modern day Iraq. It dates to the Ubaid Period, so is at least 6000 years old.

31-17-318

31-17-318, before treatment (BT)

As you can see in the above BT image, it was previously broken and repaired. In order to get it ready for exhibition, those old repairs need to be removed. We don’t always remove old repairs (and we never remove repairs that date to when the objects were still in use), but based on observations of the vessel and referencing an old conservation treatment report, I knew that the repairs had to be undone –  if left in place those old materials are likely to fail and possibly cause more damage to the object. Another goal of the conservation treatment is to improve the appearance of the vessel, as there was excess adhesive and overpaint in areas and many of the joins were not well aligned.

Based on that old treatment report and tests in the lab, I knew that the old adhesive is soluble in acetone and that the material used to fill missing areas would soften in acetone enough to allow it to be removed. So the first treatment step, after documenting the piece fully, was to put it in an acetone vapor chamber:

cup-dtdsc_0042

An acetone vapor chamber isn’t anything fancy – in this case it was created with a plastic bag. I placed the vessel and 2 small containers of acetone in the bag and then clamped the open end to prevent the acetone from leaking out. Sometimes an object only needs a few hours in a vapor chamber before it can be taken apart. This little vessel required 24 hours before even one piece could be taken off. The whole thing was finally deconstructed after a week of sitting in the chamber on-and-off and poulticing and swabbing the joins with acetone.

During treatment, after the first piece detached

During treatment, after the first piece detached

During treatment, after about half the vessel was taken down

During treatment, after more than half the vessel was taken down

Success! All the pieces are finally apart, placed on images of the vessel in order to keep track of everything.

Success! All the pieces are finally apart, placed on images of the vessel in order to keep track of everything.

Once the pieces came apart, I had to swab all the joins with acetone to remove excess adhesive and fill material. I’m now at the point where I will start joining the pieces together again.

Swabbing a break edge of a ceramic to remove excess old adhesive

Swabbing a break edge of a ceramic to remove old adhesive

Stay tuned for more posts about our work on these objects, and our continued work on the Egyptian collection and other projects!

Hello, goodbye

We have had a very special object in the Artifact Lab for a few weeks – this Predynastic ritual vessel in the shape of a woman:

E12281_at01_compressed

E12281, after treatment

This vessel was excavated at Abydos, and we estimate that it is at least 5000 years old.
Here is a view of the vessel from the top:

E12281_at06_compressedI have worked almost exclusively on organic materials in the Artifact Lab, so getting to work on this ceramic was a nice diversion. Conservation treatment, which involved some light surface cleaning and minor mending, was requested because this object will be featured in an upcoming publication. It will leave the lab today, but I didn’t want it to leave without posting an image of it on the blog! Once the publication comes out, I’ll be sure to include a link to it.

In the meantime, to learn more, follow this link to check out a video discussion of a similar vessel, in the collection at the Brooklyn Museum:

Brooklyn Museum female figure

 

A demotic jar

A pottery workshop (from LICHTHEIM Miriam, Ancient Egyptian literature, 1973)

A pottery workshop (from LICHTHEIM Miriam, Ancient Egyptian literature, 1973)

Among the objects that an archaeological conservator treats, a very important one regarding the quantity is ceramic. Ceramic artifacts are widespread on time and many very different places; a lot of (if not all) civilizations on Earth made ceramics, so if you haven’t met one of those yet in a museum, it’s only a matter of time!

The one we have in the Artifact Lab is an Egyptian jar, from one of the past Penn Museum’s excavations on this site. Jars were used to contain fluids and are covered inside with a mixture of water and clay, to make it waterproof.

Here is a picture of the fragments before any intervention:

The jar before treatment.

This ceramic is covered with inscriptions painted in black ink (most likely a carbon ink) and the writing appears to be demotic. The Egyptian writing knew three different forms: hieroglyphic, which is the one you’re used to see on monuments; hieratic, which is a simplification of hieroglyphs, allowing the scribes to write faster for their administrative work on papyrus or pottery and rock fragments; and the demotic is a simplification of the hieratic, used from the VIIth century B.C. It is one of the writing that you can see on the Rosetta Stone.

rosetta stone

Demotic writing on the Rosetta Stone.

Detail of the black inscription covering the jar.

Detail of the black inscription covering the jar.

This black ink is water soluble, meaning that water is highly prohibited to clean the inscribed areas !

Concerning its condition, the main problem of course is that the jar is broken into about 50 fragments. It was restored in the past so it still bears remains of an old adhesive on the edges and many fragments are still glued together. Moreover, the surface and the inscription are covered with dust and need to be cleaned.

P1050012

Example of a particularly dirty fragment. The inscription is barely visible.

The next step will be to remove the old adhesive and to put the fragments together again. Eventually, we may have to fill some gaps in the ceramic, so as its handling could be easier and safer.

Those steps will be more detailed in several blogposts to come !