I have been working as a Conservation Assistant at the WSHC for nearly a year, and a large part of my role involves administration and financial processing. However, one of the more interesting and slightly unusual aspects of the job is the hands-on work I get to do as part of the Conservation and Museums Advisory Service here at the centre, and I have recently undertaken training to use the x-ray machine which we have in the lab. This is a complex process which requires stringent processes, records and maintenance checks to ensure the machine is used safely and functioning correctly. Regular use of the equipment is key to building experience and a ‘feel’ for the items being investigated and how to get the strongest images.
How it works
Inside the x-ray machine is an x-ray tube. A heated filament called a cathode sits inside the tube and accelerates high energy electrons at a metal target anode, usually made of tungsten, as the electrons strike the anode they interact with the atoms. In this process, which is called Bremsstrahlung (braking radiation), the electrons lose much of their energy and a photon x-ray is produced. X-rays are electromagnetic radiation of a short wavelength and high frequency invisible to the human eye, but possible to record on photosensitive film, known as x-radiographs.
The object to be x-rayed is placed on top of a cassette which holds the photosensitive film. On exposure the x-rays will penetrate through the object leaving the image captured on the film. The x-rays are partially absorbed, “attenuated”, by the denser materials such as bone or metal and pass more easily through soft material such as soil or skin. Therefore, the strength of the x-ray (KV) and the length of time the object is exposed for is adjusted for the type of material, size and condition of the item.
The photographic films then require a wet, chemical process similar to that used for black and white photographic film with a developer solution to reveal the image, followed by a fixer to secure the image and a wash to remove all chemical residues. This process takes around an hour and half and must be carried out in the dark room, with only red light, which can be a little disorientating at first!
Digital or computed x-radiography is well established and allows greater speed in reviewing and manipulating images. CMAS are actively working to move to digital, so watch this space!
How X-radiographs are used in conservation
X-radiography produces images on a 1:1 scale which allow the conservators to investigate the structure, manufacture or identity of an object. Small dark bubbles can indicate casting processes, the distinctive herringbone structure of pattern welding or wave formations of damascening are often clearly visible in x-rays, even when the surface of a blade is severely deformed.
Moreover, x-rays pass more easily through deteriorated materials and voids, these areas will appear darker grey or black compared to the brighter white of more stable areas. This can show up pitting, cracks and breaks assisting in the accurate assessment of the condition of items and their longer-term conservation requirements.
X-radiography is a non-destructive way of retrieving and revealing information and so it is commonly used in the primary stages of investigation.
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.
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
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.
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.
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.
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.
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.
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
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.
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.
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!
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.
My name is Annette and I am an Employer Engagement Officer with Wiltshire Council working on a program called Building Bridges.
“Building Bridges is funded by the European Social Fund and the National Lottery, through the Big Lottery Fund.”
Several weeks ago, Wiltshire & Swindon History Centre & Building Bridges set out on a journey of discovery and learning with five would-be archivists with a love of all things past. You could say a real ‘Throwback Thursday’ as this is the day we came together to indulge in something we all love: history.
I can’t believe we have nearly come to the end of our first but I hope not last ‘Archive to Survive’ project.
After attending a learning symposium facilitated by Wiltshire Museum & Heritage Service and hearing a presentation from The Museum of London and the work they were doing with Autism in Museums I was buzzing - I couldn’t wait to do something similar.
Lucky for me I had already formed a working relationship with the fabulous Heather Perry -Conservation & Museum Manager who was nearly as excited as me, and completely on board.
We decided we wanted to target our project at those who may have found it hard to gain paid employment due to anxiety, depression, or other barriers. We wanted to promote confidence and skills learning that would support their journey, and give them a sense of wellbeing and inclusion.
So along with my Building Bridges partners in crime Lorraine, Laura and the lovely Sophie, Conservator (Archives) at the History Centre, we set about putting our plan into action.
If you are reading this it is possible you will know that in Wiltshire & Swindon we have an amazing purpose-built facility that holds the county wide archives. What you may not know is that the public can come in and research things from family histories, to who lived in your house 100 years ago. To do this every document held at the centre needs to be catalogued and this is where we came in.
We wanted to offer an opportunity for a group of people to come in and work with trained professionals to learn all about maintaining and cataloguing this amazing resource. Preserving it for future generations and so Archive to Survive was born.
We recruited five like-minded participants with a love of history and our journey of learning began back in August. Since then we have come together every Thursday and have been building on our confidence and skills, and form new friendships.
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).
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:
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
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).
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.
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?
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.