A Game-Changing 2 days in Stirling

Historic Environment Scotland: Monuments in Monuments 2019
Monday2 September  – Wednesday 4 September 2019 Engine Shed, Stirling

Meredith Macbeth – Conference Review

Autumn has absolutely flown by and the Monuments in Monuments 2019 Conference seems like a distant memory, but for me, the impact certainly lives on. MiM 2019 took place over three days in early September 2019. The speakers ranged from the technical to the theoretical. There were case studies and papers on policy, and a big focus on climate change and its effects on the historic environment. To catch up with friends old and new and to find out what lies in the heart of stone conservation today, all from the hub of the buzzing Engine Shed in Stirling made the experience more than beneficial. Attendees were able to explore notable sites in the Central belt which really gave the opportunity to tap into the work that is being done in Scotland. Delegates were able to choose from  Fossil Grove, Glasgow Cathedral or  Glasgow Necropolis on the first day. On the third day, delegates were able to choose between Dunblane Cathedral/Leighton Library, British Geological Survey or the South Gyle Conservation Centre. With such interesting options, it was hard to choose! And while I was unable to attend it, the ceilidh at Stirling Castle appeared to be a massive hit with more than a few bleary eyes and heads the next morning!

Monuments in Monuments 2019: the beginning of the conference.

I am fortunate enough to have a “dream position” job with Orkney Islands Council working at the extraordinary St. Magnus Cathedral – where I am the sole Stone Mason/Conservator. The job has its challenges but being able to exist within the red and white sandstone walls of St. Magnus is an absolute privilege. My tasks are quite varied from taking lime samples and helping to plan our next 10 years of work, through to changing lightbulbs and clearing drains. Every day is different and with big works on the horizon, every month and year will be different. Sourcing local stone continues to be a tough issue and working within a Council budget and bureaucracy also continues to be an opportunity for a challenge, although slightly less fun than taking samples from closed quarries.

I was given the opportunity to attend MiM 2019 and represent ICON Scotland as a representative on the Group’s “Trade Stand”. I was absolutely delighted to represent ICON Scotland and had many interesting chats with fellow members and interested parties while answering queries on the stand.

Meredith Macbeth representing ICON Scotland on the Group’s “Trade Stand”.

I found myself thinking “What a fast two years it has been since I attended the opening of the Engine Shed!”. I am always so pleased to step over the threshold as I know I will be greeted by a group of cheery folks passionate about the historic environment. Arriving at MiM 2019 was no different and more exciting as an international conference, we had the opportunity to ‘show off’ the Engine Shed and the impressive works undertaken by Historic Environment Scotland (HES).

I’ve been working in conservation since 2008 and I was really struck at this conference to see the radical improvement and accessibility of technology since then. It was exciting to see technology being assimilated and used well, primarily for documentation and interpretation. It was brilliant to see and certainly encouraged me to “up my game”. The use of drones (Brian Johnston, Queen’s University) for example, time-lapse cameras, (Sarah Hamilton, HES) thermal imaging (Kinley Laidlaw) and not to mention all the 3D recording. Exciting times! Inspired by this conference, I have recently employed Orkney Sky Cam to survey our East Window, internally and externally. Having such a set of high-resolution photos and videos is so useful for planning and worth their weight in high-level gold!

I found it incredibly heartening to see the community that came together at MiM 2019 with conservation as a common interest. There were speakers from all over the world including Ethiopia, New Mexico, Switzerland, Isle of Man, Washington D.C. and Italy all sharing their cultures, work and concerns, absolutely wonderful to see new sites and ponder new challenges. Blen Gemeda’s (Oxford University) talk on medieval rock-hewn churches in Ethiopia was visually stunning and an interesting challenge. The ongoing preservation of the inscriptions at El Morro National Monument by Angelyn Bass and Katharine Williams (University of New Mexico) was intriguing, not only the history of the inscriptions themselves but the history of the conservation of the inscriptions themselves.

Another unique question which was discussed at this event was the footprint of the Conservator. Should viewers and historians be aware of conservators’ interventions within the history of the object?  It was even asked- should a conservator always intervene? This was such an alluring topic, as so many treatments of the past have been done in good faith but certainly to the determent of the object or site itself; Portland Cement has kept a good many stone conservator in employment. Paul Wooles intriguingly discussed the merit of ferrous fixings, asking if  Conservators are too quick to remove them. Yes, I thought, they can be hazardous to stonework but at the same time, they are fabulous tell-tales for moisture movement and often part of the history of the object. Ending the conference was David Harkin from HES, speaking about ‘Cultural Heritage and Climate Change’. I have seen David speak before and he is always a delight, albeit his subject matter less cheery and optimistic. He manages to explain how climate breakdown impacts our everyday lives, but also how it will impact our historic building stock. This can be useful to raise the awareness of a modern conservator. Those treatments that worked in the past may not work now – due to our changing climate.

Although I have many colleagues, I am a one-man-band when it comes to the conservation and stone care at St. Magnus Cathedral. Conservation, in general, can involve quite a bit of solo work, so for me coming together with fellow professionals for a few days in September was much needed.  I have mentioned a few examples that really inspired me, but so many other little snippets have stuck with me – Christine Bläuer’s keynote advice on how to translate the meaning of your results to the stakeholders has helped me in my work. Christa Gerdwilker’s advice to take a holistic view and be able to question your approach has helped me too. A keynote tip from Sara Croft – that we should champion our profession and the skills, knowledge and judgment that we all bring to our own jobs was massively inspirational. Also Sara’s advice about setting out on the Accreditation process – don’t hold back there, get involved.

It was a wonderful few days and I would like to thank Christa Gerdwilker and her team for pulling together such an inspirational event.

Meredith Macbeth is the Stone Mason/Conservator at St. Magnus Cathedral, Kirkwall, Orkney. You can contact her at meredith.macbeth@orkney.gov.uk or on her sleepy twitter account @MeMacbeth.
Many thanks again to Christa Gerdwilker, ICON Scotland, Orkney Islands Council and the Friends of St. Magnus Cathedral for making this opportunity possible.

 

Using scientific analysis to investigate the unusual discolouration of a David Livingstone letter

In this week’s blog, find out how conservators from the National Library of Scotland and National Museums Scotland have been using scientific analysis to discover more about a letter by famous explorer David Livingstone…

The National Library of Scotland’s collections include a considerable number of letters by David Livingstone, most of which are written a on a white laid paper with an address embossed on the top right corner of the first folio.  One of these letters is strikingly different from the others in its appearance, and the reasons for this were recently investigated in a collaborative heritage science project between the Library and National Museums Scotland. The project team comprised Lore Troalen and Jim Tate from NMS and Isobel Griffin and Simona Cenci from the National Library of Scotland.

The letter in question (Acc.13333) (Fig.1), dated 16 April 1865, is written on a very brittle paper that shows a dark, uneven colour. Apart from the colour, this paper appears to be the same as the white paper used by Livingstone for the other letters he wrote around this time, with an embossed address in the same place. This suggests that the dark colour may be the result of chemical degradation, rather than the way the paper appeared originally. However, the discoloration is more severe than the yellowing which often occurs as paper ages, for example as a consequence of exposure to light.

Acc.13333 showing the brown colour of the paper

Acc.13333 showing the brown colour of the paper

Scientific analysis was proposed to investigate the nature of the degradation processes that lead to the brown discolouration, which would be of general interest and of practical use in determining whether or not to attempt to remove the discolouration. Additionally, it was hoped that some information about the various coloured inks in the letter might be obtained. The analysis was undertaken non-invasively using X-ray fluorescence (XRF) and Scanning electron microscopy in Backscattered mode/energy dispersive X-ray Spectroscopy (SEM-BSC/EDS), with the SEM in Envac mode.

Results

XRF results

The analysis of the ink with the XRF was problematic, because the beam size (about 2 mm x 1.5 mm) was larger than the ink marks, making it difficult to separate the ink from the paper surrounding it, not to mention the paper underneath the ink. However, the results suggested that all of the inks seemed to be iron based, with traces of copper and zinc, and possibly more zinc in the brown ink.

With regards to the paper itself, the XRF showed significant amounts of sulphur and iron, with the iron present in higher concentrations in the darker areas of the paper. This was interesting because in the previous analysis of various other papers of a similar age, NMS has not detected iron at comparable levels.

SEM/EDS results

The SEM-EDS analysis confirmed the presence of iron in the ink that was tested, as shown in the images below.

The area of ink which was analysed using SEM-EDS

The area of ink which was analysed using SEM-EDS

Image above: A detail of an area of writing; the green colouring shows the presence of iron, corresponding to the places where ink is present, and showing that the greatest concentration is where two strokes of the pen overlap

Sulphur was also present in the ink, as seen in the spectrum below. Other elements present in smaller amounts were calcium, sodium, magnesium, aluminium, silicon, phosphorous and potassium, also with zinc in some samples. All samples showed high levels of carbon and oxygen.

With regards to the paper, the elements detected were iron, sulphur, magnesium, aluminium, silicon and calcium, again with carbon and oxygen.

EDS spectra for an area of ink (red) and an area of paper (yellow). The elements zinc (Zn), potassium (K), sulphur (S) and iron (Fe) are notably higher in the ink.

EDS spectra for an area of ink (red) and an area of paper (yellow). The elements zinc (Zn), potassium (K), sulphur (S) and iron (Fe) are notably higher in the ink.

The SEM images of the surface of the paper at high magnification showed in fascinating detail how the ink cracks as it dries out, forming a surface layer which partially obscures the paper fibres.

SEM-BSC micrograph of a rectangle of the paper measuring about 0.6mm across, showing  a line of ink running up the centre

SEM-BSC micrograph of a rectangle of the paper measuring about 0.6mm across, showing a line of ink running up the centre

The SEM images also show small and generally angular particles present amongst the paper fibres. The fact that these particles show up brightly tells us that they contain elements which are different from the paper fibres.

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Discussion and conclusions

Calcium, iron and sulphur are known to be commonly found in iron gall inks, with the concentrations of other elements varying depending on the provenance of the ink[1]. Given that calcium, iron and sulphur as well as zinc were all found in significant quantities in the inks tested, and that the inks are brown in colour, they seem very likely to be iron gall inks.

It is possible that some of the elements found in the paper may be from water soluble components within the inks, dispersed through the paper by wetting, although this seems unlikely to be causing such a general brown colour throughout the paper.

Various reasons for the dark brown colour of the paper were proposed by the project team:

  1. It could be due to darkening with smoke, which seems plausible because sulphur as well as carbon is present;
  2. Since iron is present, it could be due to particles of iron oxide, which were possibly introduced through storage of the letter in a damp and rusty container;
  3. It could be an organic coating such as oil or wax, which would be difficult to detect with XRF or SEM/EDS; such coatings were sometimes applied to make paper more translucent, although a translucent paper would generally have been used for a copy of a letter and this letter seems unlikely to be a copy because it has an embossed address.

If the small, angular particles seen in the SEM images are the substance causing the brown discolouration of the paper, their appearance makes them more likely to be a sooty material or iron oxide than an oil or wax. However, it is also possible that they are a calcium compound introduced during the manufacturing of the paper.

Hence the analysis raised as many questions as it answered, and there were many suggestions for further testing, which could include:

  • Further SEM-EDS analysis, to identify the elements present in the small, angular particles seen in the SEM images;
  • Preparation of replicas to introduce soot and iron oxide, followed by analysis of the replicas and comparison of these results to the results for the original letter;
  • SEM imaging of some of the other letters written by Livingstone at around the same time, followed by morphological analysis of the images to establish whether all of the letters were written on the same type of paper[2];
  • Analysis of the letter to look for organic oils and waxes, for example with Fourier transform infrared spectroscopy. Although it seems unlikely that the paper was coated with oil or wax, it would be helpful to eliminate this as a possibility.

If resources permit, we will tackle some of this analysis in the future, and the mystery of the brown discolouration may be solved. Until then, the letter will remain untreated. And who knows – perhaps it will remain that way forever as a testimony to the letter’s unusual storage history, be that in a smoky room or a rusty old box!

For more interesting conservation conundrums and heritage science research, please follow the National Library of Scotland and National Museums Scotland on Twitter (@NLSColl_Care; @ConserveNMS).

[1]                      García, J.A., Ruvalcaba Sil, J.L. and Meeren, M.V. (2014) ‘XRF Study of Mexican Iron Gall Inks: Historical and Geographical Overview of their Chemistry’, MRS Proceedings, 1618, pp. 31–41. doi: 10.1557/opl.2014.453.

[2]                      Kazuyuki, E., Masato, K., Masuchika, K., Barnard, M., Matsuoka, K. and Whitfield, S. (2007) ‘Analysis of morphology and elements on the paper specimens of the Stein collection of the British Library’, in Tradition and innovation: proceedings of the 6th IDP conservation conference, eds. L. Shitian and A. Morrison, National Library of China, Beijing, China, pp. 37-51.