Ungluing, re-gluing and filling the jar.

Posted on March 3, 2014 by lauragalicier

Statuette of an egyptian potter at work (beginning of the 2nd mill. B.C).

The next step for the Egyptian jar was un-gluing all the fragments …to glue them together again.

We had two different cases: fragments that remained adhered together and fragments that were already separated, bearing remains of an old adhesive on their edges. The old adhesive had to be removed since it had many negative issues. First, it prevented the fragments from being joined back together by creating an unnecessary thickness at their junction. Moreover, when reconstructing the ceramic, the old adhesive prevents the fragments from fitting together well.

This old adhesive had a light brown color and after a few tests, it was found to swell when warm water was applied on it.

Here is what it looked like:

Detail of the break edge of one of the fragments, after applying water steam.

To remove the adhesive from the break edges, we used a Preservation Pencil, a tool looking like a pen and emitting water steam. Once softened, the adhesive was very easily removed with a scalpel or a brush.

And here is the result :

The same fragment edge after the removal of the old adhesive.

For the fragments still adhered together, it was a little more difficult since the water had to penetrate inside the jar but not too much because of the water-soluble ink on the surface. Compresses, or poultices, of water were applied on the interior of the ceramic, to cover the breaks. Most of the fragments fell apart quite quickly contrary to areas where the jar was very thick.

Now the building could begin ! … well almost since it was necessary to plan precisely how to proceed and in which order to arrange the fragments. First, we had to find where each of them was going, to estimate the losses. For that purpose every fragment was given a number and they were located on a map so as to keep track of their location.

The map; the numbers were indicated on the fragments with blue scotch tape.

Then the gluing really began, using the conservator’s favorite adhesive: Paraloid B72, diluted in acetone.

First steps of the gluing.

The more the jar grew, the more it needed a support, first on the outside, since its bottom is rounded….

A good support was provided by this bucket filled with glass balloons, heavy enough to stabilize the jar.

…then on the inside to prevent it from collapsing on itself because of some particularly heavy fragments.

The jar was growing and needed internal support; the white material inside is a plastic bag filled with polyethylene fiber.

Losses in the ceramic had to be filled at the same time as the gluing to provide structural support to the jar and prevent it from collapsing. Moreover those areas to fill would have been difficult to reach once the gluing was complete.

There was one large loss that definitely needed to be filled since one of the surrounding fragments was holding by only a few millimeters to another one.

Filling this area was a bit tricky. The fill material needed a support to be applied on the jar. Japanese tissue paper was glued inside of it and strengthened by applying several layers of Paraloid B72. It also needed to be shaped according to the curve of the jar.

On the left: The area to be filled. On the right: Japanese tissue paper used as a support to hold the fill material.

On the left: The inside of the jar with the “tricky fragment” held in place by the japanese tissue paper. On the right: Applying the fill material.

The fill material used is a mixture of Paraloid B72 and glass micro-balloons, looking like a very light white powder; plaster is also traditionally used to fill losses, but glass micro-balloons are lighter and don’t bring any salts to the ceramic. That kind of fill is also reversible and completely neutral towards the ceramic.

Here’s the fill once finished and polished with a heat spatula, ready to be painted.

The fill almost finished: the building can go on.

More fills and building to come in a next post !

Cleaning the jar

Posted on January 27, 2014 by lauragalicier

A previous post introduced you to this demotic jar, currently on view in the Lab. The first step in its treatment was to clean the surface, which was very black due to dust.

It was necessary to make some tests on the ceramic to determine which way to clean was the best, meaning the safest for the object. Indeed, the black inscription on the jar is fragile and water sensitive. The first rule was to choose a non -aqueous method, that’s why I first thought about…erasers !

Image showing cleaning tests on a fragment of the jar.

Test 1 : Sanford Magic Rub Eraser. Test 2: Staedtler stick eraser.Test 3 : Latex eraser.

Test 4: Ethanol

Test 5: Wishab eraser.

As you can see on the picture, the erasers seem to be the best choice, especially the n.2. Indeed, it can be applied with different levels of strength according to the amount of dust to remove.

Ethanol was also to be tried, being a “light” solvent; but the issue with a solvent is that you can’t control how it penetrates in the material, especially with a porous ceramic. So the best choice seemed to be the Staedler eraser.

It was then time to test this cleaning method on the inscription.

Cleaning test with the eraser on an inscribed fragment.

The eraser appeared to work well, removing only the black grime and not the inscription. Of course, one has to be careful with this method, and not to press the eraser too hard or the black ink could disappear as well !

So I went on and cleaned all the other fragments.

Fragment before cleaning.

The same fragment after cleaning.

In a general way, cleaning an object is very rewarding for a conservator, because the result can be seen at once. And pictures taken before and after are often impressive.

However, some things could not be improved; many demotic signs are lost due to water damage that occurred in the burial environment so the text isn’t complete. Moreover, a few fragments didn’t change after being cleaned, and still look dusty even if they aren’t.

Here is the general result, after all the fragments were cleaned.

General view of the fragments before cleaning.

General view of the fragments after cleaning.

Next step: de-gluing the fragments !

The heads in color.

Posted on January 12, 2014 by lauragalicier

If you’ve been following the Artifact Lab blog you are now familiar with the two Egyptian wooden heads and the work in progress on them. Those heads are complex since they are composed of several materials that the conservator has to understand to treat them.

So let’s explore an important but now almost lost of their aspects: polychromy. Indeed, 99% of the colors on the heads are lost but some remains allow us to figure out what colors were originally theirs.

Mapping of E17910 red paint layer.

Let’s have a look at the real colors left on the heads:

E17911 – On the left: Detail of red paint on the left ear (x 10 magnification) ; On the right: detail of blue paint on the the wig located on the right of the head (x 10 magnification).

E17911 – On the left: detail of black paint on the the wig located on the right of the head (x 10 magnification) ; On the right: Detail of red paint on the left ear (x 10 magnification).

E17910 – Detail of the red paint above and under left eye and red paint below the right eye (x 10 magnification).

The wig is black (even if it looks blue on the picture !). The red is ochre, produced by reducing iron oxides to powder.

All Egyptian statues (and generally statues from other ancient civilizations) were completely painted. Only a few of them had their polychromy preserved, and it is especially rare on wooden artifacts because of many alteration factors that damaged these objects. The two heads were buried in a grave, several feet underground and the groundwater could rise very irregularly and completely overflow the tomb and its contents. The wood suffers a lot from humidity changes: indeed, this material always tries to keep its own moisture content stable, according to the environment moisture. That involves cycles of giving off and taking moisture; if those cycles occur too many times, the wood can’t follow and breaks generally appear.

If the wood is covered with a polychromy layer, it falls off since it can’t follow the movements of the wood. The wood is also susceptible to damage by other substances, like different types of salts and other alkaline substances whose action is increased by humidity.

That’s what explains that on the heads, the few areas of color left are in a bad condition; let’s try to explain what’s going on under the sediment!

To give you an idea, here is a stratigraphic representation of what a nice and undisturbed polychromy (if that exists!) should look like:

The wood is covered with a preparatory layer; it allows the surface to be even so that the paint layer can stick better to it. That’s it about the theory, let’s see what we have in reality:A lot less pretty and legible ! We can’t say whether the preparatory layer exists or not, and the paint is covered with a modern application of paraffin wax that wasn’t applied correctly on the wood; indeed the white material that covers some areas of the surface and of the polychromy is a paraffin deposit.

White paraffin deposits on the paint and the wood.

E17911 – The paint layer is poorly attached to the surface and termites didn’t spare it.

The paint layer is poorly attached to the wood and the paraffin used to strengthen the heads in the field (during the 19^th century) is the only thing maintaining them.

While we are grateful that there is still some polychromy remaining…paraffin isn’t such a good thing ! It will be the topic of a next post to come.

A demotic jar

Posted on December 17, 2013 by lauragalicier

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.

Demotic writing on the Rosetta Stone.

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.

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 !

First step for the heads

Posted on October 30, 2013 by lauragalicier

Last week I introduced you to two wooden statue heads that I’m working on and promised to share the step by step process of their conservation.

A first step in understanding these objects is gathering information about their past. As we said in the previous post, they are from Dendera and were discovered in 1898. The other questions were: Who discovered them? How and when did they arrive in Philadelphia? And more…

To address these questions, the best place to begin is the Museum Archives. I first checked Clarence Fisher’s field notebooks, since we know that he excavated in Dendera for the museum from 1915-1918, continuing the work begun by Charles Rosher and Flinders Petrie. An afternoon looking at (all!) of his notebooks revealed no leads. The other possibility was to refer to Petrie’s own field records; and here I found reference to the heads, or more precisely the “statuettes”, noted in his field notebook.

This page notes the “2 statuettes” at the foot of the coffin.
From Petrie Notebook n.15, p.30, courtesy and copyright of the Petrie Museum of Egyptian Archaeology, UCL.

That mystery solved, we moved onto the next one. Included in the storage drawer with the wooden heads, we found a note indicating “2 wooden statuettes nearly consumed by white ants”.

After a little more digging, I found that this was a quote from Petrie’s publication about Dendera, on p.10, paragraph 2…and the rest is still meaningless to us! In this publication Petrie indicates that the heads came from a secondary burial, belonging to a woman, under Adu II’s own funerary chamber.

Moreover, it unveiled a new clue: Petrie wrote that he discovered “statuettes” and not only their heads. That could imply the fact that they were still complete statues at the time of the excavation. It is possible that they were in such a poor condition that the archaeologist left the bodies and only took the heads. We definitely do not have any more parts of these statues in our collection – after checking, no “spare bodies” are registered in the Egyptian storerooms of the Penn Museum.

All of this may seem to be only details but it is essential information for a conservator: the fact that W.M.F. Petrie discovered the heads is highly interesting, because he most likely treated them in the field. He published a book where he explains his practical way of applying a “first-aid” treatment to damaged artifacts (Methods and aims in Archaeology, 1904) which may provide critical information for us! Indeed, knowing this will allow the conservator to be aware of what kind of material was added to the original object and how to deal with it.

My investigation into these old treatment materials will be the topic of a post to come!

About two wooden Egyptian heads…

Posted on October 23, 2013 by lauragalicier

“You have a wonderful job!” It’s a sentence that a conservator often hears. But what is really this incredible job? I propose to you to have a closer look at what a conservator usually does by following step by step the conservation of two artifacts recently arrived in the Artifact Lab.

Not really the glamorous objects you imagine when you think about Ancient Egypt, right? But they can reveal so many things to us.

Let’s begin with all what we knew when they arrived in the Lab: these artifacts are two Egyptian wooden statue heads. They bear remains of polychromy (blue and red painting) and have inlaid eyes. In their storage drawer were three labels: one quoting a publication about Dendera (the place where they were excavated) describing the heads, and two others mentioning a previous treatment in 1965 with an adhesive called Vinylite. Other information about these objects came from our curators, who knew that the heads are from the site of Dendera, more precisely the mastaba of Adu II, excavated by Flinders Petrie, a famous British archaeologist. Moreover, the heads are from the Sixth dynasty (2374-2140 BCE). That’s all we knew about those two heads before beginning our work !

Let’s have a closer look at them…

Left: one of the wooden heads viewed in profile. Right: a front view of the other wooden head.

A long quest is ahead and we’re only starting to think about an appropriate conservation treatment. Indeed, before any scalpel reaches their surface, we need to gather as much information as possible about the artifacts. Stay tuned to hear more about our discoveries and the decisions that we make based on what we learn.

In the Artifact Lab

Tag Archives: Dendera