Let the Treatment Begin!

Abigail Duckor

Following the research conducted by Claire d’Izarny-Gargas, further examination led to the formation of treatment plans for Angel A and Angel B. As discussed earlier, Angel A was in decidedly better condition, so it was tackled first.

Claire starting the treatment on Angel A

Claire starting the treatment on Angel A, courtesy of Norfolk Museums Service, T1878333.

On the front and the back of the angel were two different types of surfaces. The front was a gilded layer, which was flaking and delaminating. The back featured a painted layer, also undergoing flaking, but not as extensively. The front and the back of Angel A therefore underwent different treatments. This blog post discusses the relaying of the flaking gilded surface. For the front of the angel the main goals were to clean the surface (which was very, very dirty!) and to relay the remaining flakes. An initial gentle clean was done with a cotton wool swab and a solution of 50:50 IMS (industrial methylated spirit) and deionised water. This method was selected after some cleaning tests were carried out in an inconspicuous area.

Cleaning tests on Angel A.

Cleaning tests on Angel A. Courtesy of Norfolk Museums Service, T1878333.

The flakes were then relayed by first saturating the area with the 50:50 IMS/ deionised water solution. Then, using a small brush, a drop of warmed gelatin solution (5% w/v in deionised water) was placed under the flake. Saturating the area first reduced the surface tension and allowed the gelatin to penetrate under the flake.

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The gelatin was dissolved in warm deionised water. It was kept at 60°C in a water bath. Photograph by A. Duckor

After the gelatin cooled a bit (a few minutes), heat was applied to the area with a heated spatula. A piece of silicone-release paper was used between the  spatula and the angel, to prevent damage to the surface from the tackiness of the gelatin. Pressure was gently applied to the flake with the heated spatula, in a ‘rubbing’ motion. The gradual heating softened the gilding and allowed it to be re-shaped onto the surface of the angel. The heat ‘activated’ the gelatin and adhered the flake onto the substrate.

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The heat spatula and brush used in the flake relaying. Photograph by A. Duckor

This method was very successful in relaying the flakes with little breakage. Following re-laying, further cleaning could be done without risking additional damage to the surface.

The left hand of Angel A before and after the flake relaying. Courtesy of Norfolk Museums Service, T1878333.

The bulk of this treatment took place during the summer months of 2014 and allowed for the involvement of both MSc and MA conservation students – a great opportunity to work together and learn from one another!

Erin Murphy using the heat spatula to gently press down a flake and seal it with the gelatin.

Erin Murphy using the heat spatula to gently press down a flake and seal it with the gelatin. Courtesy of Norfolk Museums Service, T1878333.

Rachel Altpeter and Romina Quijano Quinones working together.

Rachel Altpeter and Romina Quijano Quinones working together. Courtesy of Norfolk Museums Service, T1878333.

Yuqi Chock applying gelatin to flaking areas of gilding.

Yuqi Chock applying gelatin to flaking areas of gilding. Courtesy of Norfolk Museums Service, T1878333.

Photographs by A.Duckor and Claire D’Izarny-Gargas.

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Work Placements – transitioning from the UCL conservation lab to a professional institution

Veronica Ford

So far in this blog we have seen a lot of stuff from the current inhabitants of the UCL conservation lab. As you know from Megan’s introductory post, the MSc in Conservation for Archaeology and Museums is actually a two year course.

“But what about last years’ lab students? What are they doing?” I hear you cry.

In the second year of the MSc for Conservation for Archaeology and Museums, students are assigned work placements lasting a total of 10 months to give them experience of the reality of the working environment (in other words – it’s a wake up call!).

My placement has been divided between two institutions. Between September and December, I spent time with the preventive conservation team within the Bodleian Libraries. From January onwards, I’ve moved on to the Ashmolean Museum of Art and Archaeology, both institutions located in Oxford.

The past six months have been a massive learning curve!

When people think of conservation they might imagine a lab-coated conservator gluing an object back together.

Something like this. Which sometimes is the case, nevertheless (photo courtesy of Naomi Bergmans).

Something like this. Which sometimes is the case, nevertheless (photo courtesy of Naomi Bergmans).

But in reality the role is far more diverse than that!

The two institutions I have been hosted at have been quite different (though very close to each other geographically). At the Bodleian, I was part of the preventive conservation team, ensuring that objects are kept in good environmental conditions (including temperature, humidity, light exposure, and so on) and that they are well stored and handled in order to minimise damage. I was also involved with the environmental proving of a new library building. This meant consulting with builders, contractors, other conservators, librarians, and curators. It also required a scientific approach to understanding the environmental factors that might adversely affect the storage of library materials. As part of this we implemented a dust monitoring programme in the new library, and carried out research into pest eradication.

The view from my office in the Bodleian wasn't half bad (photo courtesy of Veronica Ford).

The view from my office in the Bodleian wasn’t half bad (photo courtesy of Veronica Ford).

At the Ashmolean, however, I have focused more specifically on interventive conservation (i.e. the active treatment of deteriorated and broken objects). In addition to object treatments, I have been involved in a broad range of museum activities including pest monitoring, condition assessments, loans and exhibition installations.

No complaints about my view from the Ashmolean either (photo courtesy of Veronica Ford).

No complaints about my view from the Ashmolean either (photo courtesy of Veronica Ford).

The two experiences combined have shown me the true breadth and diversity of activities with which conservators are involved. Basically – we need to be involved whenever there is a risk that an object might be/has been damaged. Conservation treatment work needs to be fitted around this, as conservators are often required to jump in and get involved with other museum activities at the last minute. This is in contrast with my experience working in the conservation lab at UCL, where the majority of my time was spent actively working on object treatments.

At UCL, I was encouraged to gain experience with extensive research, complex analysis and challenging treatments. The need to develop hand skills and experience meant I was encouraged to undertake complicated treatments. This contrasts to some degree with my experience at a working institution, where the focus of treatment decision making is defined by the needs of the institution, and where time and resources may be limited.

Two previously restored ceramics with two different approaches (before treatment). Left - that undergoing treatment at the Ashmolean. Right - that treated at UCL (photos courtesy of Veronica Ford).

Two previously restored ceramics with two different approaches (before treatment). Left – that undergoing treatment at the Ashmolean. Right – that treated at UCL, Copyright UCL Institute of Archaeology Collections (photos courtesy of Veronica Ford).

This is clear in my approach to two archaeological ceramics both with broken Plaster of Paris fills, one of which I treated at UCL and one of which I am currently treating at the Ashmolean. My approach at UCL was thorough: I removed the old adhesive from the ceramic and reconstructed it from the beginning with conservation adhesive (Paraloid B72*), creating structural fills only where necessary. At the Ashmolean, I have decided to replace and repaint the broken fills, avoiding a complete deconstruction. This conserves time and resources and offers the least interventive approach, whilst still stabilising the object and fulfilling treatment goals.

I have learnt that it is necessary, in a professional context, to be pragmatic and realistic. This however need not be an obstacle to more in-depth research projects. The Ashmolean is always looking for new ways of researching and analysing the collection and recently received funding to carry out analysis on 500 objects belonging to the recently acquired Wellby collection.

It is hard to be glamorous when you work on a building site: moving special collection material into the new library building (photos courtesy of Veronica Ford and Naomi Bergmans).

It is hard to be glamorous when you work on a building site: moving special collection material into the new library building (photos courtesy of Veronica Ford and Naomi Bergmans).

At times conservation work can seem unglamorous or routine. But such activities are absolutely vital for the preservation of collections. For instance, an important preventive conservation activity is condition checking new acquisitions, to ensure that they are not actively deteriorating and can be safely stored with other collection material. This can sometimes result in rather difficult and less pleasant working conditions.

Spores for thought: checking new acquisitions for mould at the Bodleian (photo courtesy of Veronica Ford).

Spores for thought: checking new acquisitions for mould at the Bodleian (photo courtesy of Veronica Ford).

Conservation is often a controversial activity and it can be hard to balance established conservation approaches with increasing pressure on heritage institutions to maximise access to, and use of, collections. I am finding that essential conservation skills include the ability to negotiate with others, to communicate conservation needs clearly and accurately, and also to show willingness to be flexible and compromise where necessary. Although, in theory, this is clear to many conservators in training, the lesson cannot truly be learnt without direct experience.

* An ethyl methacrylate copolymer. Just in case you are wondering.

Acknowledgements: Thanks to my lovely work placement hosts at the Bodleian and Ashmolean and to Naomi Bergmans for some of the photographs.

A Glass Puzzle from Tell Fara

Emily Williams

Image Of The Glass Sherds Before Treatment. Copyright UCL Institute of Archaeology Collections

When I first came across the box full of archaeological glass fragments in the conservation lab, it raised a strong sense of curiosity and concern – I did not want the box of bits to go back to the collections store in the same condition, and without knowing what this golden iridescent glass used to be. The box contained 19 fragments, too few to make up a whole vessel, so early on, I had to abandon any idea of being able to reconstruct a complete object. After many hours of research, and what felt like the longest, most complicated puzzle I had ever done, I was however able to piece enough fragments together to infer the shape of a bottle.

Reconstructing the bottle. Copyright UCL Institute of Archaeology Collections

Once I had identified that the fragments formed a bottle, I attempted to reconstruct it. The glass was however too fragile to handle without the surface layers becoming detached. Before I could do anything else, I needed to consolidate the surface. This was done using very low percentage of Paraloid B 72 in acetone. I carefully applied this solution so that the polymer went under the delaminating flakes in order to reattach them to the underlying glass.

Making the Fill using Japanese Tissue. Copyright UCL Institute of Archaeology Collections

After I consolidated the surface, I put the fragments together with a more concentrated solution of Paraloid B 72. Stronger epoxy adhesives are often used to reconstruct glass objects in collections (like Hxtal NYL-1), but was not used with this archaeological object as the treatment would not have been so easily reversible. The potential for conservators in the future to retreat our conserved objects is always considered when we make decisions about our treatments now. I then used watercolour paints to colour Japanese tissue a very pale blue/green and sandy yellow in order to match the colour of the glass underneath the layers of corrosion. The tissues were shaped by hand, cut to size, and then attached as a support to the reassembled glass fragments.

The Reconstructed Base of the Bottle. Copyright UCL Institute of Archaeology Collections

For the upper section of the bottle, I experimented using a light bulb as a base to create my rounded fill. Shaping Japanese tissue so that it remains curved can be quite tricky. My lab partner Robert suggested I coat the light bulb in a thin layer of silicone to create a barrier between the two, this allowed me to remove the tissue from the light bulb surface once it had dried. I used T40 Silicone Rubber from Tiranti, which is a two part thixotropic mixture with a curing time of approximately 30 minutes.

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Using the Silicone covered light bulb as a mould for a Fill

One complicated aspect of the reconstruction was having to figure out how to reconstruct a closed vessel when the only opening was through the very small and narrow neck of the bottle. Once I had all my tissue supports in place, I inserted a bent wooden stick with a flattened silicone tip so I could reactivate the adhesive with acetone and use the silicone tip to press the tissue onto the glass from inside the bottle.

Glass Irridescence On The Inside Of The Bottle. Copyright UCL Institute of Archaeology Collections

Finally, the glass bottle reconstruction is now complete! The object will be returned to the UCL Institute of Archaeology’s Palestine-Petrie Collection, and is now readily available for teaching and research.

Image of the Bottle After Treatment. Copyright UCL Institute of Archaeology Collections

The Writing on the Sherd

Megan Narvey

One of the objects I am in charge of this year is this small ceramic pot, belonging to the Petrie Museum of Egyptian Archaeology:

Before Treatment photo of the archaeological ceramic in question. Courtesy of Petrie Museum of Egyptian Archaeology, UC65224

Before treatment photo of the archaeological ceramic in question. Courtesy of UCL, Petrie Museum of Egyptian Archaeology, UC65224

One of the interesting things about this object is that it was excavated by a rather famous early archaeologist, Sir William Matthew Flinders Petrie. Petrie is famous in archaeological circles as a pioneer of modern archaeology, implementing methodical techniques and caring about the small details.

Portrait of Sir William Matthew Flinders Petrie, 1903

Portrait of Sir William Matthew Flinders Petrie, 1903

Petrie’s legacy was visible right on the inner wall of one of the large sherds on my pot – the blue pencil markings were identified as belonging to him. Unfortunately, they are very difficult to read.

This blue pencil writing belongs to Flinders Petrie. Courtesy of UCL, Petrie Museum of Egyptian Archaeology, UC

This blue pencil writing belongs to Flinders Petrie. Courtesy of UCL, Petrie Museum of Egyptian Archaeology, UC65224

The pot had undergone a previous treatment some time in the past that had now failed, leaving several sherds detached, as you can see in the first photograph above. Additionally, the pot had survived not one, but two historic fires! This had left a thick layer of soot on the object, which you can see below. In order to remove it, I had to spend a lot of time testing different cleaning methods and looking at the surface of the ceramic very closely.

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Courtesy of UCL, Petrie Museum of Egyptian Archaeology, UC65224

There was an exciting and unexpected consequence of spending a lot of time cleaning the sherds –  I saw strange shimmery lines underneath engrained soot on one of the fragments, almost invisible to the naked eye. In order to figure out what I was seeing, I looked at the fragment with an infrared (IR) Dino-Lite, a handheld digital microscope. The infrared rays, with a longer wavelength than visible light, allowed me to not only see more clearly, but take close up images of what was hiding under the soot.

Here is an image of the sherd under normal light:

An image of the fragment with the hidden writing. Can you spot it? Courtesy of UCL, Petrie Museum of Egyptian Archaeology, UC65224

An image of the fragment with the hidden writing. Can you spot it? Courtesy of UCL, Petrie Museum of Egyptian Archaeology, UC65224

In contrast, here is what was captured with the IR Dino-Lite:

The IR Dino-Lite images of the hidden writing.

The IR Dino-Lite images of the hidden writing.

I also annotated the photograph on Powerpoint so that the writing was bright red, making it easier to read:

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Whatever is written here is very similar to and in much better condition than the original and much more obvious writing, even under the same conditions!

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I now need to help to identify what is written. What do you think? Can you decipher what Petrie has written?

 

Characterization of Gilding Layers on Gilded Wooden Sculpture

Claire d’Izarny-Gargas

Back to the stunning pair of Angels from Blo Norton Hall Chapel – see the first post in the series here.

Angel A (right), and B (left). Courtesy of

Angel A (right), and B (left). Courtesy of Norfolk Museums Service, T1878333.

Before proposing a suitable conservation treatment for the Angels, we needed to better understand how they had been made and the causes of the dramatic flaking of the gilded layers on both Angels.

An initial examination showed that they were covered by several layers of gilding and that the detachment of the surface appeared to be at the same layer on each of the Angels, revealing the mordant of an older gilding layer. The high degree of damage and the shiny/waxy appearance of the uncovered mordant suggested that some change had occurred between the two gilded layers, causing the detachment of the outer gilded layer. It also appeared that the mordant was composed of wax, rather than animal glue, which is a more commonly used gilding technique. Further analysis could help to confirm this, and would give a better understanding of the composition of the successive layers added to the surface, and an idea of the type of gold used – was it pure gold leaf or an alloy?

Detail showing two gilded layers on the arm of Angel A. Courtesy of

Detail showing two gilded layers on the arm of Angel A. Courtesy of Norfolk Museums Service, T1878333.

Detail showing the yellow 'waxy' mordant on the dress of Angel A. Courtesy of

Detail showing the yellow ‘waxy’ mordant on the dress of Angel A. Courtesy of Norfolk Museums Service, T1878333.

Angel A was investigated by using a combination of techniques, such as micro-chemical spot testing of samples (flakes which had fallen off the statue), Fourier transform infrared (FTIR) spectroscopy, observation under ultra violet (UV) fluorescent light, thermo-microscopy and analytical studies of two cross-sections under the polarised light microscope (PLM) and scanning electron microscopy with energy dispersive x-ray spectrometry (SEM-EDS). Each of these analytical techniques enables us to characterise the materiality of the object with different degrees of accuracy. Correlating the results of the different analytical techniques would help us determine how the Angels had been made.

In this post we will talk specifically about the polarised light microscope (PLM) and the scanning electron microscopy with energy dispersive x-ray spectrometry (SEM-EDS), which are two amazing techniques that, when combined, allow us to get accurate results.

Two samples, taken from different areas of the statue, were prepared in cross-section. The cross-sections were first embedded in a resin and observed under a polarised light microscope.

Two samples of the gilded layers taken from Angel A were embedded in a resin to realize a cross section which will then be observed under the PLM and the SEM-EDS.

Two samples of the gilded layers taken from Angel A were embedded in a resin to realise a cross section, which will then be observed under the PLM and the SEM-EDS.

The PLM gives precise information about the thickness and the number of layers present in the polychrome surface. Moreover, it is possible to identify the number of gilding layers and so to give the number of gilding campaigns carried out on the statue. The use of the SEM means that the morphology of each layer can be studied under higher magnification than with PLM. Also, the EDS can provide an elemental analysis of the sample and therefore identify and precisely locate the inorganic elements present in each layer.

PLM photo showing the layering of the successive layers of gilding. Right: SEM photos, summary of the elements found and interpretation

PLM photo showing the layering of the successive layers of gilding. Right: SEM photos, summary of the elements found and interpretation

The investigation revealed the presence of three gilding layers, each composed of five distinctive layers. The gold leaf layer was made of gold alloy of copper and silver. The fillers were made of calcium carbonate, which was occasionally found mixed with clay. Furthermore, the presence of wax in the two mordant gilding was confirmed, mixed with an unknown component. Finally, the use of white lead pigment was identified alongside iron oxide. The difficulty of adhering gold leaf to a wax surface, combined with fluctuating environmental conditions over long periods of time could have been the reason for the extensive detachment at this level.