We came, we saw, we will maybe conquer … one day.

Anna Funke

Billingsgate House and Bathhouse is one of the many archaeological sites hidden beneath the streets of central London. This remnant of Roman Britain can be found in the basement of a rather unassuming office complex on Lower Thames Street, between Monument and Tower Hill.

One of the best preserved parts of the Bath House showing the underground structure of the heating system, part of the original floor, as well as a bench.  Photo Credit: Valeria Cabrera

One of the best preserved parts of the Bath House showing the underground structure of the heating system, part of the original floor, as well as a bench.
Photo Credit: Valeria Cabrera

In the 3rd century, when this House was built, it would have been right on the banks of the River Thames, providing it not only with a beautiful setting, but also with easy access to fresh water for its bathhouse and other household necessities. However, what was a very convenient feature during its occupation, has become a complicated conservation challenge today.

Although the occupants of the London area have been changing the flow of the River for centuries, the ground water table remains high and our archaeological site, in turn, remains damp.

The current setting of this Roman dwelling probably used to be much more romantic!  Photo Credit: Kristen Gillette

The current setting of this Roman dwelling probably used to be much more romantic!
Photo Credit: Kristen Gillette

Water movement through the site brings with it a rich array of soluble salts. These travel through the remains of the Bath House, while they are dissolved in water, and crystallise whenever the environment gets drier (hence the term ‘soluble’ salts). These salts are slowly but surely causing a variety of damage, including delamination of the ceramic building materials and crumbling of the original mortar.

A particularly impressive bloom of salts. Photo Credit: Kristen Gillette

A particularly impressive bloom of salts.
Photo Credit: Kristen Gillette

One of many examples of delamination on ceramic tiles at Billingsgate. Delamination is the separation of layers of material fabric.  Photo Credit: Kristen Gillette

One of many examples of delamination on ceramic tiles at Billingsgate. Delamination is the separation of layers of material fabric.
Photo Credit: Kristen Gillette

This is a complex conservation problem to solve , given that there is a ready supply of dissolved salt in the ground water and that it is not possible to achieve environmental conditions that could minimise evaporation of the water and crystallisation of the salts. One response has been to add ‘sacrificial sand’ to areas of the site around the archaeological remains. This acts to encourage groundwater to move through the sand instead of the archaeological remains, and thus reduce salt efflorescence on the actual structure. In spite of this, the salts nevertheless continue to appear on the archaeological remains. Although the salts are certainly a conservation problem in the long run, they also damage the public perception of the site as they give the impression that the Bath House is unloved and not well cared for.

Contesting this impression, students taking the Applied Heritage Management Master Class at the Institute of Archaeology work on the site every year to improve its accessibility, interpretation and condition.

The 2015 Conservation Team from the left: Kristen Gillette, Anna Funke, and Valeria Cabrera. Photo Credit: Tim Williams

The 2015 Conservation Team from the left: Kristen Gillette, Anna Funke, and Valeria Cabrera.
Photo Credit: Tim Williams

The conservation part of this project this year focused on recording the distribution of salts and the damage they have caused. We mapped the general distribution of the salts, identified areas of damage on different materials and in different areas of the site, and also compared the concentration of this year’s salts with pictures taken during last year’s survey.

Our findings point to the need to increase the frequency of regular cleaning and removal of the salts. An annual cleaning would help reduce the presence of salts onsite, and mitigate future damage from the crystallisation of salts. This would be good for the long term stability of the Bath House, but would not remove the cause of damage, as ground water continues to move through the site, depositing the damaging salts. Improving the care of the Bath House will make it more interesting and enjoyable for visitors, and this may bring about better opportunities for funding for the long-term preservation of the Billingsgate Bath House. This is just one of many examples when conservation and public engagement work towards the same goal of making heritage more accessible to a wider audience, both for the benefit of the archaeology and the people interested in visiting or researching it.

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Inpainting Decision-Making: An Introduction

Vanessa Applebaum

It’s Fashion Week in London and to celebrate the array of styles and colours I’ve seen walking through the streets, I’ve decided to speak about the nuances of colour matching when one inpaints a decorative or archaeological ceramic.*

As we saw in Emma’s post from last week, repairing a ceramic often requires the application of a fill to replace gaps or spaces, which can both recreate the object’s original form and provide it with structural support. Inpainting the filled area frequently provides it with camouflage, to avoid bringing unnecessary attention and focus to this recent addition.

One aspect of conservation that I find particularly tricky is the lack of a singular, finite answer when it comes to treatment questions. Sometimes, the correct way to proceed for one object is a completely inappropriate method for how you should handle another. An example of this is the difference between inpainting the fill of a decorative ceramic object vs. an archaeological one. Since there is no set criteria for choosing a treatment based upon object material alone, the important thing to keep in mind is the item’s context and its significance to the stakeholders to which it is connected. This will play a key role in any conservation decisions made in the future.

In year one of the MSc programme we are given nine objects of varying origin to conserve, each composed of a different material. The first two we received were ceramic—both high and low fired. Similar to Sarah’s, my high fired ceramic was a blue and white transfer print bowl from the latter half of the 20th century. It used to look like this:

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Object no. 9211 before treatment. Courtesy of Liz Pye.

According to the owner, the main objective of the conservation treatment was to return it to its original decorative function. Since the goal was to regain the aesthetic of the originally manufactured object, it would be important to colour match the fill as close to the colour of the ceramic body as possible.

After reconstructing and filling the bowl, I thought inpainting it would be the easy part. After all, the bowl was white wasn’t it…? Not so much. As it turns out, recreating a ‘white’ colour is not as simple as you’d think, and in the case of my ceramic bowl, its ‘white’ body was actually a combination of five pigments.

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The five pigments I combined to mimic the ‘white’ of my high fired ceramic

After many trials and mixing combinations, I was able to come up with the correct colour to match the bowl, as you can see below:

Colour match success!

Colour match success! Courtesy of Liz Pye.

Once I mixed the appropriate colour, it was applied to the fills and allowed to dry. Upon completion, the bowl looked like this:

Object no. 9211 after treatment

Object no. 9211 after treatment. Courtesy of Liz Pye.

The fills and inpainting can be considered successful because of their close similarity to the object’s existing colour. Because of this, I was feeling confident in my abilities to match and was quite happy that I’d cracked the correct method of dealing with ceramic fills…until I realized that was completely different to the considerations that had to be given to the inpainting of my low fired ceramic, which were two sherds** from a pinch pot dated between 3300 – 2700 BCE, spanning Predynastic and Protodynastic Egypt.

Before they were joined, the sherds looked like this:

 Object no. UC 66105 before treatment. Courtesy of UCL, Petrie Museum of Egyptian Archaeology.

Object no. UC 66105 before treatment. Courtesy of UCL, Petrie Museum of Egyptian Archaeology.

Unlike the high fired ceramic, the objective for this treatment was to stabilize the object for future handling and use in a university research collection. The sherds needed to be reattached, with fills added for structural support. Like the bowl, these fills needed to be inpainted so that the repair wasn’t distracting when viewing the object; however, unlike the bowl, the colour of the fills needed to be distinct from the ceramic body. This is because the object will be studied and viewed in the context of its place in an archaeology collection, and so there should be no question as to what is newly added and what is original to the manufacture and use of the object. This presented the challenge of coming up with a colour that would simultaneously look similar yet different to the original.

In the end, the following effect was created on the area of fill through paint layering and surface finishing:

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(Courtesy of UCL, Petrie Museum of Egyptian Archaeology, UC 66105.)

Both of these inpainting jobs were considered successful because they weren’t judged by the same set of criteria. Instead, conservation methods were created from the context clues and significances that were applied to them. For someone who used to study scientific and mathematical concepts  that purported to have ‘right’ and ‘wrong’ answers, this was a departure from my comfort zone. That being said, the problem solving that conservation encourages and the creativity that I now enjoy were things that I quickly learned to appreciate. …And as an entirely added bonus, I can now say that I understand colour matching as well as those down at London Fashion Week.

*Ceramic – a material composed of inorganic compounds of varying compositions, which can be high fired fired (porcelain) or low fired (terracotta flower pot).

**Before anyone thinks this is a typo and that I meant to say ‘shard,’ ‘sherd’ is a term often used to describe archaeological ceramic fragments.

“Shorty, you’re my Darling Angel…”

Jan Cutajar

Forget Shaggy and that catchy tune, drum-roll on cue, allow us to introduce you to two fascinating objects, straight from heaven above.

Fig. 1: Ladies and gentlemen, we present to you Gabriel and Gabrielle (blandly named Angel A (right) an B (left) respectively).

Ladies and gentlemen, we present to you Gabriel and Gabrielle (blandly named Angel A (right) and B (left) respectively). Courtesy of Norfolk Museums Service, T1878333.

Well, more precisely, this stunning pair of wooden gilded statues is originally from Blo Norton Hall Chapel in the Breckland district of Norfolk. They have recently been entrusted to the UCL Institute of Archaeology Conservation Department, by Norfolk Museums Service,  as they were in need of some tender care. In this first chapter of our series on this ongoing conservation project (run by fellow MSc. Conservation colleague Claire D’Izarny-Gargas at UCL Qatar and us students in London), we shall first describe the initial condition of the angels we have come to love here at the conservation lab. So, without further ado, let’s jump into the thick of it!

Both angels had their outer gilded layer present in a state of dramatic flaking, such that the gold leaf was detaching all over the surface and uncovering the remains of earlier gilded layers. A detailed physical examination revealed that several campaigns of gilding had taken place. Further examination was not easy as the extent of surface delamination meant that handling the object was not possible without risking further surface losses. The following photos reveal the extent of this damage:

The faces of both Angel A (left) and Angel B (right) had particularly suffered from surface delamination. Courtesy of Norfolk Museums Service, T1878333.

Fig. 3: Angel B was in much worse off a state than A - note the extent of flaking as well as the acuteness of the flaking (not to mention all the dust!).

Angel B was in much worse off a state than A – note the extent of flaking as well as the acuteness of the flaking (not to mention all the dust!). Courtesy of Norfolk Museums Service, T1878333.

Fig. 4: Whilst Angel B suffered on the front, Angel B had more severe problems on its back, where delamination had taken place to reveal the various gilding campaigns, painted layers and ground layers. Although rather despairing, the deterioration allowed insights into the preparation of the object during its creation.

Whilst Angel B suffered on the front, Angel A had more severe problems on its back, where delamination had taken place to reveal the various gilding campaigns, painted layers and ground layers. Although rather despairing, the deterioration allowed insights into the preparation of the object during its creation. Courtesy of Norfolk Museums Service, T1878333.

From these visual observations, it was clear that the sensory significance of the objects was being compromised and necessitated immediate recourse. This was also since both angels were missing fingers and Angel A in particular was suffering from a fractured arm!

In the next chapter, join us as we report the analytic tests and research which were undertaken to  further comprehend the active deterioration and finally guide the treatment choices for the angels.

N.B. All photos by Claire D’Izarny-Gargas.

Clothes Moths: Know Thy Enemy

Letitia Steer

In the spotlight today are two  types of moths that are a perennial problem for conservators in the UK. The culprits discussed in this blog attack museum objects (especially taxidermy and animal specimens),  as well as  damaging carpets and clothing in domestic environments. They may go unnoticed now,  but as spring arrives beware, they take no prisoners!

A victim – this poor penguin is currently being kept as an example of moth devastation. Courtesy of UCL, Grant Museum of Zoology, LDUCZ-Y1601

The two types of moth in today’s crimes-against-conservation spotlight include the common or webbing clothes moth (Tineola bisselliella):

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Adult webbing clothes moths caught in pest trap, the back has a golden sheen

and the case-bearing or case-making clothes moth (Tinea pellionella).

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An adult case bearing moth, with a silvery sheen (image from Wikipedia, ©entomart)

 

The common or webbing clothes moth

The larvae of this species spin silk tubes or sheets of webbing across the material they are eating, under which they can freely move over the surface, chomping as they go.

 

FACT: These villains not only hide in the shadows but are capable of laying  batches of up to 100 eggs on fur, feathers, skin, wool or other protein-containing  materials. The adult moth lays the eggs (the larvae), which cause the damage when they hatch from the eggs and spin silk webbing as they feed and grow,  before pupating and hatching out as adults to mate and lay eggs​ to keep the cycle of destruction​ going.

 

The case-bearing or case-making clothes moth

The larva spins a case or bag around itself, leaving the ends open so that it can use its jaws and legs. It then eats as it crosses the material, carrying its case and leaving a trail of grazed textile or fur with fragments of excreta or frass. The larva molts within the case, and when fully grown it pupates within the cocoon. Eventually the adult moth emerges to mate and lay eggs. Infested material is often littered with empty silk bags or cases, which resemble grains of rice.

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The larvae hatching, leaving behind its frass (image from Wikipedia)

Mythbuster: Clothes moth eggs will not remain dormant in textiles and then hatch many months later!

 

Though this post concludes the first critter watch, this post serves as a warning and highlights the need for vigilance in museum stores,  inside the conservation labs and offices of UCL, and at home!

 

 

Conservation Tool Spotlight: Silicone Brushes

Madeline Hagerman

No, not like this one. (Image from Wikipedia).

No, not like this one. (Image from Wikipedia).

This past summer in the midst of writing our MA dissertations, we received a list of tools to purchase. As I perused the list, I felt a bit like Harry Potter, new to the wizarding world, reading his school list for the first time. While the list included familiar items from my oil painting days, such as a plastic spatula, it also specified the need for “Needle holder, with rustless chuck” and “Paint brushes (sable, squirrel and hog’s hair).”

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I may have been a little too enthusiastic in my purchasing of bamboo skewers.

I decided also to buy silicone brushes on the advice of a former MSc student. Silicone brushes, you may ask? Yes. Though not like the lovely pastry brush above.

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Voilà!

They come in different sizes as well. From tiny (Size 0, top), for detailed work, to more moderate sizes (Size 2, bottom) for general purposes.

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They have been especially helpful for work on my delicate porcelain teacup. I used my brush to apply Araldite 2020 (an epoxy resin) to the joins of the cup. This method of application utilized the tight nature of porcelain fractures to allow the epoxy to be drawn into the join through capillary action. I also used my silicone brushes to fill the small chips on the joins of the teacup.

Applying Araldite 2020 mixed with polyester pigments to fill a chip in the interior surface of the teacup.

Applying Araldite 2020 mixed with polyester pigments to fill a chip in the interior surface of the teacup.

The owner had specified she wanted the cup to be fully restored to its original appearance. As such, I infilled the gold paint around the rim. I used a silicone brush to make sure all of my lines were straight. They were well-suited to this task because they easily wiped the excess paint off of the surface of the teacup.

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Fellow conservation student Kristen Gillette also used silicone brushes to fill chips on her high-fired ceramic.

 

Making sure the inpainting lines are all straight.

Making sure the inpainting lines are all straight.

Silicone brushes are not only good for porcelain and other high-fired ceramics, but also especially useful for glass repair and restoration.

Abby Duckor, lab partner extraordinaire, uses HXTAL (another popular conservation epoxy resin) to rejoin a practice piece of broken glass.

Abby Duckor, lab partner extraordinaire, uses HXTAL (another popular conservation epoxy resin) to rejoin a practice piece of broken glass.

Silicone brushes have become a bit of a lab sensation. They are useful for the application of all manner of adhesives: epoxy resins and Paraloids a là the ubiquitous B-72, to name a few. In the restoration side of conservation, the brushes allow conservators to easily create small epoxy resin fills. Because they don’t stick to paint or most adhesives, they can be used to clean up inpainting from smooth surfaces, like glass and resin. Silicone brushes are definitely my favourite conservation tool!

*As a North American student in London, Harry Potter continues to provide many of my points of comparison for British life.

The Eviction of Zuul: Paper poulticing food stain from a high fired ceramic

Sarah Giffin

We begin the story with an unassuming blue transfer print bowl, probably from the 1970s:

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So clean. So white. Nothing that would ever make you think “Gee, I think there might be a food stain permeating the entirety of this ceramic” or “Perhaps this bowl is actually a portal into the underworld”. Nothing except a little bit of stain along the fracture surface of the big fragment.

Because I am a student, and because we are encouraged to try out different methods of treatment, I decided that it would be interesting to try to poultice the stain out of the break surface. For those uninitiated in the ways of the paper poultice, poultices are usually used to try to draw a stain out of a semi-porous material through capillary action; as the surface of the poultice dries out with evaporation, the stain is moved out of the wet porous material and into the paper on top. That being said, the first step was to soak the bowl to maximize the efficacy of the poultice.

That’s when I got my first glimpse of the demon stain, which the lab named Zuul (from Ghostbusters!).

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So I decided to soak the bowl to move the stain around as much as possible…

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All of that orange is food stain. Food stain seeping from the depths of the bowl.  Who knew an otherwise white bowl could contain so much orange? It’s probably tomato soup or gravy that over the years soaked through the cracks in the glaze as the bowl was eaten out of repeatedly.

I originally decided to poultice just the edges, but found that it wasn’t sufficient. That was, until I made a discovery…

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That orange spot is a piece of paper poultice that accidentally fell on the glaze surface.  Zuul has turned the paper bright orange as it comes out of the glaze. After this miraculous discovery I decided to change my strategy to full surface poulticing.

I poulticed…

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And poulticed…

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And poulticed…

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And I poultice some more for two and a half months until I could poultice no longer, and still Zuul continued to ooze from the depths.

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Sometimes we wondered whether or not this was still stain or portal to the spirit world. Unfortunately, although much of the food staining (Zuul) was removed from the bowl, stain still remains particularly in the glaze cracks. This means that the future treatment of this bowl will involve controlled bleaching to try to eliminate the orange colour.  However, bleaching will not physically remove the stain like poulticing did.  It will only eliminate the orange colour from the surface of the stain.

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Although the soaking and poulticing treatment ended up causing residual staining in the glaze, it proved to be an excellent learning experience for me. Not only was I able to see how readily stains can mobilize when soaked in water, but I also became a poultice-making pro, and can now expertly apply an effective poultice in a variety of methods.  But let this serve as a warning:  don’t eat out of dishes with glaze cracks.  If you do, Zuul might make an appearance again.

An Introduction

Megan Narvey

Welcome to the conservation lab at UCL’s Institute of Archaeology in central London!

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Here, students in the MSc Conservation for Archaeology and Museums learn the practical techniques and critical thinking skills necessary for a career saving innocent objects from horrific fates like bronze disease and improper storage.

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The Institute of Archaeology has been the home to conservation students for many years, as conservation was first established at the Institute of Archaeology in 1937 (thankfully, the labs have been refurbished several times since then). If you look closely, you can see that years of students have made their mark on the lab. These little random inside jokes spread throughout the lab are one of my favourite parts about working and learning here.

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Myself and the other MSc students in the lab are in the middle of a three year course on the conservation of objects at UCL. The first year consisted of the MA Principles of Conservation, a course studying the theoretical basis of conservation and its management. Next came the MSc, where we spend one year in this lab and another year in internships across the United Kingdom.

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This year we work on a variety of objects, from ceramics and glass to metals and organic objects, from archaeology, social history, and ethnographic collections. We also participate in a variety of related projects: conducting collections surveys, developing outreach programs with communities and for small museums, doing conservation science research, and much more. We tend to be very busy.

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Here at Conservation Lab Chat, we hope to open this busy lab up to those who might never otherwise visit (although we love visitors!). We will regularly post about our projects, treatments, and the other interesting things that happen in the lab. We hope you enjoy your time here. Welcome to the conservation lab, and welcome to our little corner of London!

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Postscript: If you like this, you should check out the other conservation blog at UCL, which talks about modern conservation issues and news: Conversations on Conservation of Cultural Heritage.