Alexis North is the Project Conservator for the Egyptian Storage Move Project, Penn Museum.

Since my first post, I have been working steadily on stabilizing the painted wooden boat model. For a bit more background, this boat model was excavated from Sedment, a cemetery site about 100km south of Cairo.

Map of Egypt showing the location of Sedment and other cities. Source: Google Maps

A number of First Intermediate Period (2250 – 2061 BCE) tombs were uncovered, including that of Khentkhety, a middle-aged man who was buried in a shaft tomb with a separate burial chamber that was bricked up after interment. Sir Flinders Petrie, the archaeologist who excavated at Sedment, described Khentkhety’s tomb as “the finest burial that we found,” (Petrie and Brunton 1924, 11) even though it had been robbed in antiquity. His mummy was placed in a rectangular wooden coffin, similar in style to the coffin of Ahanahkt. According to Petrie, the wood of the coffin was so damaged by termites that it could not be moved. A detailed colored drawing was made as a record of the interior decoration, which was elaborate:

Colored drawing of the interior of Khentkhety’s coffin, depicting offerings to the deceased. Source: Petrie and Brunton 1924

Several wooden models were also removed from Khentkhety’s tomb, including two boats, a granary, and several human figures. The boat model I am currently treating, which represents a sailing boat, was found on the ground outside the burial chamber, where it had been either moved or dropped by the tomb robbers.

To return to the present day, the first and most obvious issue which needed to be addressed for this model was the actively lifting and flaking paint. In order to determine the best materials and procedure to follow, I and some of my fellow conservators performed spot tests with water, solvents, and adhesives. This involves applying a very small amount of each material to an inconspicuous area of the object to be treated, and watching for any reaction, like darkening or staining. Luckily, the surface of the boat model did not react negatively to any of the materials tested, and I was able to move on to treatment.

I began by consolidating the paint on the exterior sides of the boat. I wanted to stabilize the sides first because it was very difficult to handle or move the boat at all when so much of the exterior paint was so fragile. For each lifted area, I started by applying a drop of ethanol, which cuts the surface tension and allows the consolidant to flow more easily underneath the lifting paint. Then I used a very small brush to apply 1% Methylcellulose in deionized water. The water in the adhesive helped to relax the lifted paint, and after a few minutes I could gently push the area down until it made contact with the wood underneath. It is a bit difficult to see in photographs, but the consolidation has worked really well so far in relaxing and readhering the paint:

Before (top) and after (bottom) consolidating the areas of lifting paint.

I am also keeping a detailed record of where I am applying the consolidant. Documentation is an important part of conservation treatment, so future examiners know what is original and what has been added to the object over time. These records can also alert a conservator to any additional changes in the object’s condition.

An annotated image showing all the spots I consolidated, what material I used, and where I performed spot tests.

In working closely on the exterior surface, I have seen several areas where it appears a resin or surface coating was applied. I do not know right now whether this is ancient or modern material, but that is something we may be able to find out in the future using different analytical techniques. What I can see now is that these areas show preferential damage, where the applied material has shrunk and become brittle, pulling the paint away from the wood beneath it.

Image of the bottom of the back of the boat. The green areas indicate where the applied resin has run down the bottom, and there is now preferential loss to the paint in those areas.

If the material is modern, I may decide to try and remove it before it can cause further paint loss. If it is an ancient application, however, we want to preserve it as part of the object’s construction. The areas will be documented carefully, and monitored for future changes.

I have now finished the sides of the boat, and am moving on to the top, where some of the most significant flaking is. I will be back with another post soon to show the progress!

Sources:

Horne, Lee. Introduction to the Collections of the University Museum. Philadelphia: University Museum, University of Pennsylvania, 1985.

Petrie, W.M.F. and Brunton, G. Sedment. British School of Archaeology in Egypt Publications, v.34/35, 1924.

http://www.ucl.ac.uk/museums-static/digitalegypt//sedment/index.html

Egyptian wooden statue of Ka-Aper, also named
the Sheikh-el-beled, from the Vth Dynasty,
decorated with inlaid eyes.

Quite a while ago, we dealt with the treatment chosen for the two Egyptian wooden heads and now it’s time to talk about its results. Let’s focus on the cleaning of the surface: the goal was to remove the paraffin that certainly masked other remains of the painted layer.

First of all, we have to talk about the notion of original surface and original level.

> The original surface is composed of the original materials, before they were buried and underwent an alteration process. Concerning the heads, it corresponds to the paint layer they were decorated with.

> The original level is a layer of altered material that took the place of the original material but remained at the same level as the original surface. A good way to understand this is to think about a fossil: it is no longer the original animal, insect or plant made of flesh, bones, shell that it used to be…but you can still identify its shape since it was precisely petrified by another material. That’s what we can call the original level of an object surface.

It was necessary to define what the original level was on the heads, so as to know how deep the cleaning could go. It had to keep its meaning regarding the object itself. The paint layer was a good clue since these colored patches were all that remained from the original surface. As far as we could see, the rest of the surface was more or less corresponding to the original level. Indeed, there was no important gap between the painted areas and the present surface.

Original surface and original level near the wig of E17911, x7.5 magnification.

Another issue with paraffin was to think about how much of it we wanted to remove. Indeed, this sticky layer seemed to be what was holding the elements of the current surface together. That was especially true about the painted areas. Concerning the wood, we could only suppose that the paraffin had penetrated inside on a few millimeters only (thanks to a few articles that were published and gave estimations of paraffin migration inside archaeological wood) since we had no way to obtain an accurate estimation of this. Therefore, we didn’t want to remove it completely from the wood because it could threaten its stability and cause the wood to crumble.

That’s why the cleaning began with the known rather than with the unknown: the painted areas were cleaned from the paraffin that covered them. Thus, we could see their real extent. However, the pigments remain stuck in a thin paraffin layer but their legibility was improved, as you can see on these pictures:

Pictures of E17911’s right cheek before and after cleaning, x7.5 magnification

Pictures of E17910’s chin before and after cleaning, x7.5 magnification.

E17910’s right eye, before and after cleaning.

Then began the exploration of the unknown side of the heads, meaning the rest of the surface, where the presence of areas of paint was only a supposition.

This part of the work was really the longest since we couldn’t know what to expect under the paraffin and sediment layer. Some days, only a centimeter square could be cleaned ! Cleaning was carried out using a binocular microscope, in order to see precisely what happened under the scalpel blade and to be able to stop whenever it was necessary.

We found some new paint areas, generally rather small, sometimes buried under a rather important depth of sediment.

Example of two new painted areas on E17911, on the wig (on the left) and next to the right ear (on the right).

The biggest surprise happened with E17910 :

E17910 before and after treatment: a wig is now visible.

Close-up on the wig on the right part of E17910.

E17910’s face before and after, with other remains of a wig.

The cleaning allowed us to reveal a wig on the right side of E17910 and some other elements belonging to it on the face. We now know more details about the heads and they are almost able to be studied.

See you at our next post to learn more about the remaining steps of this treatment.

Example of the burial environment of two wooden Egyptian
Statues in Saqqara (from HARVEY, Wooden statues of the Old Kingdom, plate I).

The cleaning of the two heads is now in progress, and almost finished on the head with the wig.

But first, let’s talk about the main problem concerning those heads: paraffin. Thanks to W.M. Flinders Petrie’s publication about his preservation practices in the field (PETRIE, Methods and aims in archaeology), we knew in advance what to expect. He wrote that he used paraffin wax, almost at its melting point, to impregnate wooden objects that were very damaged. Using paraffin for that purpose, and on many other materials, was very common from the 19^th to the first decades of the 20^th century. Thanks to it we have artifacts instead of wood powder, which nevertheless presents some issues !

As far as we know, the heads were found very decayed and couldn’t be lifted from the ground. To facilitate their removal, the paraffin was spread on them while still half buried. That explains the current condition of the surface: here the paraffin takes several shapes.

White deposits (seen in photos below) on the surface are due to an application of paraffin in a non-optimal? environment. Indeed, the paraffin is brought to its boiling point and is supposed to remain warm enough to flow far inside the porous material. If it doesn’t, you might obtain something like this :

White deposits on the surface, due to the precipitation of paraffin applied in the field (magnification x10 and x25).

Those deposits cover the eyelids and the polychromy too (magnification x12,5 and x50).
On the left: Yes, this yellowish tube-shaped material is paraffin !

More paraffin, covering the red polychromy on E17910 (magnification x25 and x20).

And here is what the surface looks like:

Detailed view of the surface, similar on both heads (magnification x12,5 and x50).

Sediment (sand, quartz), and some vegetal particles, were stuck to the surface and it has never been cleaned since the discovery in 1898. The general texture can be described with a single word: waxy ! The paraffin was spread on the entire object, including the surrounding sediment. That’s why we have so much sand, quartz and organic elements included in the paraffin layer. That is particularly a problem for a conservator because the layers on an object generally have different textures that help us understanding the general stratigraphy. It also helps to guide the cleaning.

Several methods of cleaning were possible, all involving mechanical work, with a scalpel and requiring many hours of work ! The subtle aspect of this treatment is that we don’t want to completely remove the paraffin because it seems to hold what remains of the wood together. It’s like a shell of paraffin and inside is the wood, its cells completely disorganized as the CT-scan helps to figure out.

CT-scan picture of E17911, showing the damaged structure of the wood.

Here is what wood is supposed to look like when well-preserved:

Example of the CT-scan of a Japanese wooden statue from the 18th century CE, conserved at the Field Museum, Chicago.
The wood growth rings are clearly visible and the structure appears to be in very good condition.

So, removing the paraffin would be both dangerous for the object and impossible. It was decided to remove, as far as possible, the layer that prevents us from knowing what the real condition of the object is. And it certainly hides more polychromy, especially on the head E17911. Cleaning tests indicated that in addition to mechanical cleaning, other cleaning methods are needed to reduce the paraffin on the surface.

First possibility: solvents. After trying several, it appeared that it wasn’t the best solution because this method was slow, not so efficient and penetration of the solvent into the material can’t be controlled.

Second possibility: heat. This More precisely a lamp with a bulb that provides warmth. Once warm, the paraffin melts and is much easier to remove mechanically. However cleaning the polychromy has to be carried out when the object is “cool” because of its fragility. This is the cleaning method that was ultimately chosen.

General view of the heating process.

And many things were hidden under that waxy layer…