Collaboration Project with Glamorgan Archives Conservation Department On ‘Of Mouse and Manor’ Project

After a much too long break in writing here, I am going to describe a bit about a collaboration project that I was a part of this last Tuesday. Glamorgan Archives, with the help of the National Manuscripts Conservation Trust (NMCT), is currently working on conducting the conservation of four parchment (animal skin) maps of the year 1622 that were drawn with iron gall ink (or possibly carbon black pigment) and hand painted with green, red, yellow, white and blue pigments. The maps themselves are survey maps (which are rare in medieaval times, as written surveys were much more common until the late 18th century) completed by Evans Mouse for the St. John manor estates in Barry, Fonmon, Lancadel and Penmark. The project is cleverly called ‘Of Mouse and Manor’.

The condition of the maps is not great, as seen in the pictures. The parchment has become hard and rigid with a loss of opacity resulting in cockling (undulating surface). There is a loss of  paint and ink, mould stains, visible nail holes can be seen on the perimeter from previous mounting, small tears and missing areas, as well as old repairs to contend with as well that is beginning to cause damage. One map, the map of the Barry estate, has been cut into eight pieces adhered and sewn (with a sewing machine) to a textile support with missing areas from the cutting.

 

The issue that arose is with the proposed plan for the conservation that includes humidification, which entails placing the maps in a humid environment so that the parchment can absorb the moisture. This is necessary in order to remove old repairs and to re-introduce flexibility back into the parchment so they can be flattened. The main issue is the possibility of the presence of arsenic in the pigments layers (mainly green). If the treatment is performed without knowing this, there is potential health hazard with working on the material using this method. Therefore, with this possible risk identified, it is necessary to research and analyze the pigments to ensure that proper health and safety measures can be taken by conservation staff to ensure a safe working environment for all.

For my part in this, as most of you know, I am currently a volunteer at the archives during my masters program in conservation at Cardiff University. As such, this project was seen as a great way to collaborate between the two conservation labs, especially since a good rapport already existed. So, as the archives was in need of specialist analytical equipment to analyze the pigments, and I was already experienced with working with the equipment they wished to use, I was able to help organize the part of the project that brought the maps into the conservation laboratory at Cardiff University for pigment analysis using X-ray Fluorescence spectrometry (or XRF, as we conservators call it). Help was provided by Chris Wilkinson, a PhD student in Conservation at the university, as he has a great amount of experience on the XRF and provided guidance when needed.

Now, for those that don’t know what this is, here is a brief description of how it works (mind, this is very brief). The concept of the XRF is to analyze a sample using the theory of x-ray fluorescence.  The acceleration of x-ray particles through the surface layers of the sample, in this case pigment and parchment, is used to create a movement of electrons within the molecular structure of the elements present, resulting in a release of energy. This energy displacement data is gathered, and with the computer software S1PXRF, the information is converted into a spectrum with peaks at specific energies. Knowing the energy of the peaks that correspond with specific elements allows for the identification of the elements present. This is a great way to complete analysis that is non-destructive, if the only knowledge needed is the presence of elements and not the compounds that the elements form.

Caveat: Using x-ray particles, it is necessary to ensure that all health and safety guidelines were followed. As such, the maps were placed inside of an x-ray chamber (normally used for taking x-radiographies) during analysis to trap any back-scatter radiation produced.

To ensure that adequate data was taken, the machine was set to specific specifications: 40 kV (voltage), 35 µA (current), no filter, and run for a time of 180s. Each pigment colour analysed was sampled in three areas, for reproduciblity in results and to ensure that what was found is found over the whole pigment, and not just in a single spot. Backround (or a sample of just parchment without pigmentation) was also taken to discover which peaks were attributed to the parchment. With these parameters chosen between Chris and myself. The analysis progressed. After 5 hours, the analysis was complete, with the result that no arsenic was found in any green pigment. But it is useful to note that the reds used were found to have mercury, whites contained lead and yellow was comprised of iron. With this information, conservation can progress with a solid understanding of the proper health and safety requirements to follow while working on the map.

Many other benefits were gained as well: specifically a greater understanding of a very useful non-destructive analytical technique, a greater understanding of the paints and pigments used in the early 17th century, and of the benefits that are obtained by collaboration projects. Collaborations, I have learned, open doors for businesses that for one reason or another don’t have access to specialist equipment and knowledge, and, for those donating time and equipment, it provides the opportunity to expand their network (always a good thing) and expand their focus on the specialist equipment, that it may have many other uses than what it has been used for in the past, or even to spread the knowledge that has been gained by access to the equipment.