Conservation

Notes on the Conservation of a Very Fragile Letter

on Tuesday, 27 August 2019. Posted in Archives, Conservation

A new project recently appeared in the archive conservation lab: a brittle and damaged looking document that turned out to be an interesting new accession.

Letter Sent to Francis Yerbury, 14th May 1747 (1387/1697)

The document is a letter sent to local Clothier Francis Yerbury in 1747. It is thought that he may have run a cloth mill in Trowbridge although the letter is about a mill in Bradford-On-Avon. Hanne Dahl, Exhibitions and Collections Officer at Trowbridge Museum has transcribed the letter and below gives an overview of the its content:

The letter seems to consist of two messages. One is regarding a cloth order which John Howell has received and is ensuring Francis Yerbury he will pay for. The other is a new cloth order for the Empress of Russia of Clergy cloth in scarlets and greens. 5 cloth samples of Yerbury’s are attached to the letter as a colour reference.
The Empress mentioned was probably Elizabeth of Russia who lived 1741-1762. According to popular history clothing was the chosen means in Elizabeth’s Court by which to display wealth and social standing and according to historian Mikhail Shcherbatov (1733-1790) her court was “arrayed in cloth of gold, her nobles satisfied with only the most luxurious garments, the most expensive foods, the rarest drinks, that largest number of servants and they applied this standard of lavishness to their dress as well.’ Hanne Dahl, Exhibitions and Collection Officer, Trowbridge Museum April 2019

The new accession was passed on to the archives here at WSHC by Hanne after being in the care of the Ponting family; the late Ken Ponting being former Managing Director of Samuel Salter Ltd. weaving mill in Trowbridge.

As is often the case with the documents I work on, there is much of historical interest and I could spend many hours researching them. However, as a conservator, once I have enough detail to inform my conservation decisions, I must tear myself away from the fascinating historical insight and prioritise stabilising and preserving the letter so that future researchers can access it safely.

The letter

It was originally folded to be posted and has the postal address visible on one of the folded sections. The letter is written in brown ink and has textile samples and a small part of a wax seal attached.

Several factors made this a conservation challenge; not only was the paper extremely thin and fragile but the additional attached textiles samples and seal remains also had to be considered at all times as they could easily become detached and lost.

The document needed to be packaged so that it could be safely stored in the archive but also handled without the risk of further damage. As the paper was so thin, it could easily tear again with further handling, even after conservation.

I decided that once repaired, the document would be safest inside a mount- this would allow for compensation of the thickness of the attached textile samples and seal remnants as the depth of the window mount would prevent them getting squashed or dislodged in storage. It would also enable easy viewing as and when required without direct handling of the letter. Text found on the back of the letter was all in one area so the mount could be adapted to have a viewing window on the reverse. This would also mean the document didn’t need to be taken out of the mount or handled to see this.

    
Areas of damage on the letter

Backing removal

The letter arrived with us inside a frame, attached to a backing board with tape partially holding it around some edges. The paper was so thin and weak that tears had started to appear along many of the original fold lines whilst large areas were breaking around the edges.
It was important to remove the letter from the backing for several reasons; the backing board itself, made from poor quality board was likely to be causing damage to the paper. Unless they are archival quality, backing boards and framing materials are often made of very poor quality materials with high levels of acidity. As these materials break down they can transfer acidity to materials they are attached to, increasing their deterioration. I also needed to access the document to effectively repair the tears and remove the adhesive tape.

I was able to successfully remove the letter from the mount using a spatula to ease the tape away from the board surface.

Using a spatula to detach the tape off the backing board

When the board was removed it was possible to clearly see acid transfer which appeared to be coming from the document and transferring onto the backing board, suggesting the paper itself is acidic. This is likely to be due to the ingredients used when the paper was originally made, for example additives such as sizing and fillers or the materials the paper is made from such as wood pulp. The ingredients vary between paper mills and throughout the history of papermaking, for example Lignin from wood pulp is extremely acidic and is generally found in modern papers such as newsprint. This is what makes newsprint go yellow and brittle so quickly.

The darker area of brown mirrors the document suggesting acid transfer from the paper onto the backing board

After removing the document from the backing a new area of writing was discovered where the letter had in fact continued overleaf. The archivist was then able to add this to the existing transcription.

A small area of text was found on the back of the letter after it was removed from the backing board

Once the letter was separated from the backing board I could then remove the adhesive tape. This task of removing tape is always daunting for a conservator as different adhesives react completely differently to different types of removal. Sometimes it can take a long time to find a method that softens or releases the adhesive so that the tape can be removed.

On this occasion I found that applying moisture directly onto the tape was enough to release the adhesive. However, a thick piece of brown adhesive tape down the left side of the letter was so stubborn that after removing a small amount I decided it would be better to leave that particular piece of tape on rather than risking damage to the already fragile paper surface.

Once the tape had been removed I surface cleaned the document being careful to avoid any weak areas. I was then able to move on to repairing and stabilising.

Repairs

Tears on paper documents are generally repaired by adhering small pieces of Japanese tissue to the reverse.

The tissue I used for the letter is only 5 gsm, so it is extremely thin and light- but strong enough to stabilise the tears and weak areas without distracting from the letter itself.

Infills

Two areas of the document had large gaps that although supported on the back with the Japanese tissue repairs, needed to be infilled with a paper of a similar thickness to the letter itself, to prepare the document for mounting. In the conservation of archival documents (as opposed to artworks) it is particularly important that repairs such as this are visible additions, clearly seen as modern repairs and not blended to make them invisible. This ensures that future historians and researchers are aware of the difference between the original document and any conservation work that has been done.

Creating an Inlay

The edge of the letter is traced onto the inlay paper
The inlay paper surrounding the letter shown on the lightbox to highlight the small gap around the edge

In paper conservation an inlay is a piece of paper that is attached around the outside of the document to protect it and prevent further damage to fragile edges. This is achieved by tracing around the edge of the document using a needle and then removing the inner piece of inlay paper to create a paper frame. The inlay paper is attached to the document by thin strips of Japanese tissue adhered along the gap between the two. The inlay protects the original document whilst still retaining full visual access to it. It also means that the document can be attached inside the mount by putting hinges on the inlay paper rather than directly on the document itself and that the letter can be fully displayed in the aperture of the window mount without falling out through the middle.

Taxidermy Conservation

on Tuesday, 02 July 2019. Posted in Conservation

Having reached the milestone of 10 years in my current place of work, I have been reflecting on the development of my career. I think my greatest fear as a conservator is stagnation: for my work to have lost its vibrancy and draw, for my relationship with my career to have become stale.

Thankfully, even after a decade I still find daily challenges and opportunities to develop and thrive within the sector. The importance of Continuing Professional Development (CPD) is emphasised within the conservation arena; viewed as integral to the maintenance of professional standards by organisations such as ICON, the Institute of Conservation.

Being an accredited conservator (ACR), maintaining CPD is essential to retaining my accredited status. 

The CPD format encouraged by ICON allows conservators to reflect on where they have come from, focusing their aims for the future. Through a candid analysis of the strengths and weaknesses within both my team and my own armoury I was able to identify a need to improve specialist knowledge of the care of natural history specimens.

The generous award of a True Vue professional development grant allowed me to secure a place on an intensive 3 day course focusing on the care and conservation of vertebrate taxidermy specimens with Simon Moore, a subject specialist with 50 years experience.

Conservator at work

The 3 day course kindly hosted by Reading Museum allowed experience of a broad range of materials and techniques. From the art of opening historic glazed cases, without which you’d never access the specimens; to the cleaning of feathers, repair and replication of birds toes and the creation of hair plugs for a balding otter!

Otter before conservation work
Otter after conservation work

The course created a relaxed welcoming environment in which I felt able to voice my previous anxieties about tackling such materials from the risk of shattering historic glass to fears of using the wrong materials and my work ending in a terrible taxidermy publication!

The natural history collection at Reading Museum is extensive and allowed course attendees the irreplaceable opportunity to put theory into practice.

Cleaning and Care of Historic Metal Objects

on Tuesday, 16 April 2019. Posted in Conservation

What is corrosion?

Corrosion that appears on metal objects is a chemical reaction where the metal is trying to return to its natural mineral state. This often appears as green deposits on copper and red/brown deposits on iron. The main cause of corrosion on metals is a humid environment.

How do you remove corrosion?

Some corrosion is good! If your metal object has a thin dark layer on the surface this may be acting as a protective barrier from further break down of the surface. This is called patination or tarnish.

We would recommend you avoid trying to remove heavy build-up of corrosion yourself. This often needs to be done under a microscope in controlled conditions. Excessive use of polishes and chemicals (I’m including Cola and Ketchup in this!) could remove original surface so that details and decoration are lost. For example, you would no longer be able to identify the date of a coin if the surface was abraded and removed. It can also cause the metal to thin and wear down silver plating.  Chat to a conservator if you are concerned about the corrosion build up on your object or want to find the most suitable cleaning regime.

How do I care for the object in the future?

One of the most damaging things to metals is the oils and acids from our fingers, which can etch in to the surface of the metal. We would recommend always wearing cotton, nitrile or latex clothes when handling metal objects. This will also reduce marks and therefore the need for cleaning.

Giving the metal object a dust with a soft micro-fibre cloth or soft hog or pony hair brush will help prevent build-up of dust and dirt. Buffing or coating the surface with wax should rarely be necessary and should only ever be attempted after removing dust and dirt. Depending on the object and environmental conditions a wax or lacquer may be applied to protect the surface from humidity and prevent future corrosion development.

Store in an environment with a low humidity and pack using inert materials such as foam or acid free envelopes. A hoard of coins recently in conservation was packaged in individual acid free paper envelopes, sealed in a Polypropylene plastic box (recycling number ‘5 PP’) to provide a controlled environment and a sachet of silica gel to reduce humidity.

So, remember, avoid the cola and gently brush your objects to maintain a healthy patination!

Kayleigh Spring, Conservator, Conservation and Museums Advisory Service

Wiltshire Conservation and Museums Advisory Service is based at Wiltshire and Swindon History Centre. We preservice the Wiltshire and Swindon Archives and provide support to museums, heritage organisations and individuals to care for and conserve historic collections and meet professional standards.

If you have items in need of a little TLC see if our conservator can give you hints and tips for cleaning without damage, advice on storage or a to get a quote to have them repaired.

We hold regular conservation surgeries at WSHC from 2 – 4pm on the second Thursday of every month. The next one will be on May 9th. Book you appointment by calling 01249 705500.

Behind the scenes at Chippenham Museum: Reconstructing Roman Ceramics

on Wednesday, 06 March 2019. Posted in Archaeology, Conservation

A number of Roman finds were recently uncovered in the back garden of Marc Allum, a specialist on the Antiques Roadshow, during excavations organised by Chippenham Museum volunteers Clive Green and Mike Stone.

Mr Allum kindly donated the finds to Chippenham Museum. The Friends of Chippenham Museum worked hard to raise funds for the conservation of one of the finds - a fine Samian ware bowl - and conservators at CMAS were privileged to undertake the reconstruction of this beautiful piece.

The Samian ware is an example of a Dragendorff type 37 bowl, suggesting it is Gaulish dating from c. AD 70-130. The bowl has intricate decorative panels with repeating motifs of Gladiators battling wild cats and a more risqué scene thought to depict the deity Bacchus.

The Samian ware was found in 51 fragments forming almost half the bowl. Due to the fine nature of the form and decoration it was decided to fully reconstruct the piece, replacing lost areas to give more complete impression of its original form.

The conservator worked hard to piece together all the fragments. Interestingly the way the ceramic had broken into layers reveals its method of construction. Samian ware with such detailed patterns was formed by pressing clay into preformed moulds. The ceramic has split along the lines of the layers that were built up.

Graham Taylor of Potted History (@Pottedhistory) has created replica moulds for the vessel and its decorative features in order to produce a facsimile using the same techniques.

Once the form of the original ceramic was determined it was possible to create an accurate profile from base to rim using measurements of the thickness of the ceramic fragments and the diameter of the base and rim, comparing these with known examples.

The profile was used to form an accurate core in clay to which the original ceramic could be secured. Plaster replacement fills were then ‘spun’ using the profile as a guide. It was decided to only replace larger areas and those smaller areas required for strength.

Thinking of doing a work placement? My experience with CMAS

on Wednesday, 29 August 2018. Posted in Conservation, History Centre

I can’t believe that the first year of university is over! It goes so fast and with so much information it can be a bit overwhelming, but trust me, all that hard work and studying will pay off. The Conservation of Objects in Museums and Archaeology undergraduate course at Cardiff introduced me to a whole new world of practical science, as well as in-depth theory, of conservation materials and specialised equipment, such as x-ray and air abrasion machines. By the end of the year I felt pretty confident with the concept of conservation but was still nervous on how to actually apply the theory with real, archaeological objects; in a true work environment.  This is where a work placement comes in. My first-year placement was at the Wiltshire and Swindon History centre, as part of the Conservation & Museum Advisory Service (CMAS), a commercial business which deals with issues both in museums and in public collections.

Although it can seem daunting at first, this experience is essential for developing those practical skills and applying the theory with real, archaeological objects, as well as understanding the treatment of different materials and the ethical choices conservators must make; focusing on what’s best for the object and adjusting treatment plans with the client’s wishes accordingly. Keep in mind that work experience is for your benefit, so don’t panic when you have millions of doubts and questions because the people you work with are there to help you (even if you ask questions every 5 mins).

So anyway, onto the actual conservation, hooray!

First things first, you will need to assess the object just by looking at it and writing up a condition report, which simply states any observable issues with the object. The majority of my time was spent working with a Roman ceramic oil lamp in the shape of a foot! Quite a fun object from Chippenham Museum, but as you can see there is a bit of a messy application of adhesive around the centre of the lamp where it has broken in two and was re-joined.  There were also scratches, dust and cobwebs on the inside, layers of red dirt/soil on the surface as well as white flaking corrosion (see figures 1-4).

Before treatment:

Figures 1-4

Ok, so the lamp required a good clean and that adhesive definitely needed to come off. Ultimately, the decision was to completely remove the adhesive and undo the join so that I could re-attach the two pieces with a better, cleaner join.  In order to remove the adhesive, I needed to work out what solvent it was soluble in. For this, I took small samples of the adhesive from the lamp by slicing off some of the softer areas with a scalpel, under a microscope.  I then put the samples into a petri dish and tested them with different solvents (see figures 5 & 6).

Testing solvents on the adhesive:

Figures 5-6

After about 30 minutes, I could see which solvent made the adhesive go soft and rubbery. The process of removing the adhesive required quite a lot of patience as the it didn’t want to budge; a scalpel was used to remove larger chunks of the adhesive and a poultice was placed around the join. A poultice was a way of creating a solvent environment to help loosen the adhesive and separate the two pieces. 
 *Just to give you an idea of the tools used in this process, I’ve taken a couple of photos for reference.

Figure 7 From left to right – pin vice, plastic tweezers, scalpel, wooden stick and cotton wool

Figure 8

In conservation, we usually make or own cotton swabs by using a bamboo stick or cocktail sticks (depending on what you’re working on) instead of regular, pre-made cotton swabs.  Making your own means that when the cotton gets dirty it can be easily replaced and the size of the swab can be varied so you can get into the small nooks and crannies that need a good clean. It also means that we aren’t throwing away millions of cotton swabs and being more environmentally friendly.

After many tries, the poultice wasn’t loosening the adhesive, so I went in with the scalpel and pin vice to try and dig out some adhesive in the join. Another poultice was then left on for a couple of hours. When it was removed I was able to gently pry apart the two pieces (finally!) and clean the new surfaces (see figure 9).

The Conservation Team Visit Salisbury Museums

on Friday, 08 June 2018. Posted in Conservation, Museums

Conservators from the Conservation and Museum Advisory Service at the Wiltshire and Swindon History Centre have been out and about visiting museums in Salisbury. Our time visiting local museums is used primarily to provide advice and guidance on specialist aspects of caring for a museum collection. Often this involves walking a fine line, balancing the need for conservation and long term preservation of a collection with the very important need for a museum to display and allow access to its collection. For the conservation of many objects the ideal storage location would be a cold, dark, sealed box. However this is obviously impractical, not only for any museum to achieve, but is contradictory to the reason for preserving collections: allowing people to see and access items for a long time to come. Collection care is therefore a balance of risks, between what is best for the collection item and how the item can best serve the needs of the museum.

Arundells, the former home of Sir Edward Heath KG MBE, Prime Minister and Statesman, houses a diverse collection. The museum maintains Sir Edward’s home as it was at the time of his death and so collection items such as a grand piano, fabulous art works and gifts from his state visits sit side by side with yachting photographs, satirical cartoons and even a very 70’s disco shirt!

The collection item most memorable from our visit was the hand-painted silk wallpaper which lines the visitors’ route up the staircase to the first floor. The wallpaper, a gift to Sir Edward from his staff, was installed in the house in the 1980’s.

Wallpaper at Arundell 01

Keeping the location of the wallpaper at Arundells is crucial as it was purposefully created for the location chosen by Sir Heath himself. To remove the wallpaper and hide it away in dark, cold storage would irretrievably reduce its historical value. So the question is how best to preserve the wallpaper on permanent and open display in the museum?

wallpaper at Arundells 02

Historic houses often have collection items (otherwise known as fixtures and fittings), such as wallpapers, curtains, carpets and furniture which are required to be maintained in their normal settings. Curtains can best be understood as curtains if they continue to frame a window and wallpaper is best understood if it remains lining a wall. Contrary to our conservation ‘dark box’ a controlled environment is particularly difficult to maintain for fixtures and fittings on permanent display in their original locations. Particular threats to these collections are high light levels from windows and internal lighting, warm conditions from internal heating and pests.

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