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 19th to the first decades of the 20th 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 :
And here is what the surface looks like:
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.
Here is what wood is supposed to look like when well-preserved:
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.
And many things were hidden under that waxy layer…