HEAD HUNTING IN THE HIGHLANDS – Using archaeological science to understand extraordinary medieval burials from St Colman’s Church, Portmahomack, Tarbatness, Highlands

The next post in our British Science Week 2020 series is about a project supported by funding from Historic Environment Scotland, a NHSF member. 

Written by Cecily Spall, FAS Heritage

Image 1 - 3-D scans - credit Visualising Heritage, UoB
Image 1: 3-D colours scans of the skull of Chieftain A (right) showing blade cut and Chieftain B (Credit: Visualising Heritage, University of Bradford)
Image 2 - Chieftain A and skulls - credit FAS Heritage
Image 2: Chieftain A with the four extra skulls set at his head (Credit: FAS Heritage)
Image 3 - Chieftain B reconstruction - credit FaceLab LJMU
Image 3: 2-D computer-based facial reconstruction of Chieftain B (Credit: FaceLab, Liverpool John Moores University)

The Tarbat Discovery Centre, Portmahomack, opened in 1999 in the former medieval church of St Colman.  It displays the results of 20 years of archaeological research excavation focussed around this important church.  Along with National Museums Scotland, the Centre cares for the collection of burials, dating from the 7th to the 16th century, excavated from in and around the church building.

St Colman’s Church was built in the 12th century in the abandoned burial ground of an 8th-century Pictish monastery. Burials continued from the 13th to the 16th century. Over 80 medieval burials were excavated and include a small group of burials which were highly unusual, displaying burial rites never before seen.  The central burial was that of an older man – ‘Chieftain A’ – who had died aged 46 to 59 years from a horrendous facial injury caused by a blade (Image 1). On his death he was interred in a large coffin which included four extra skulls set at his head (Image 2). About a generation later his grave was reopened and the body of a second man – ‘Chieftain B’ – was laid on top with the skulls now set around his head.

A Historic Environment Scotland funded programme of archaeological scientific analysis is now underway, designed to better understand these extraordinary burials. This includes radiocarbon dating and ‘Bayesian’ (statistical) modelling of the dating brackets to refine them. The results suggest that Chieftain A died between AD1290 and 1410 and Chieftain B between AD 1380 and 1450; three of the skulls buried with them died between AD1250 and 1400 and the fourth belonged to a Pictish monk who died between AD770 and 900. These extraordinary burials belong to the period when the clan system was becoming established and so represents an important part of understanding Highland heritage and the history of the community of Portmahomack.

Multi-isotope analysis measuring strontium and oxygen preserved in tooth enamel has also provided information on region of birth with Chieftain A having grown up on or around the Tarbatness peninsula, and Chieftain B growing up elsewhere, perhaps in the Western or Northern Isles, moving to Portmahomack later in life.

Computer-based reconstruction of the face of Chieftain B has been undertaken using European datasets to model his likely appearance (Image 3), work which was generously funded by the Society of Antiquaries of Scotland. Ancient DNA analysis is also underway at Harvard University and it is hoped that it will provide information on possible family connections between the burials, as well as likely skin tone, and eye and hair colour, and perhaps even his deeper shared ancestry.

The Tarbat Discovery Centre is currently hosting a temporary exhibition on the burials project. For more information visit: http://www.tarbat-discovery.co.uk.

Traineeship in Heritage Science at Historic Environment Scotland

The latest blog in our British Science Week 2020 is written by Meghan Godley.

This is the first in a series of blogs which we will post over the next few days from Historic Environment Scotland, each of which will showcase the work of a different department. 

My background is in geology having just graduated from my master’s geoscience degree. My research looked at the geochemistry and petrology of the Ross of Mull granites, which is one area of geology that I have a very strong inclining towards. On completion of my degree I was interested in expanding my laboratory skills in a whole new sector. I always had a passion with history and heritage, so this was the perfect mix while I can still progress my learning.

The conservation science traineeship provides an excellent opportunity of experience and training in a range of materials testing and different analytical techniques, targeted towards understanding the behaviour of building materials regarding future conservation challenges, including the threats of climate change. One issue that we face when conserving our traditional buildings concerns the sourcing and replacement of historic roofing slate.

By using a piece of equipment known as a chromameter we were able to quantify the colour of different historic slates and use this information to help identify the original source region of the slates and the most appropriate replacement slates to be used.

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Image 1. Left; Chromameter analysis on a slate in the laboratory. Top Left; roofing slate from Stirling Castle Top Right, slate from Aberfoyle quarry Bottom right; Graph showing the results of analysis, highlighting the diversity of their colour in Scotland. Images © Historic Environment Scotland. 

By undertaking scientific analysis of traditional building materials and conducting on-site condition monitoring, the conservation science team supports the making of informed conservation decisions in order to protect HES’s properties in care.

One technique we use is X-ray Diffraction (XRD) analysis, which uses X-rays to determine the minerals present in a material. This technique was used to understand the composition of repair material to a window in the King’s Old Building’s at Stirling Castle. We identified that the material was made from a lime putty and contained several layers of paint, which contained white lead. Health and safety precautions were then put in place to ensure the safe removal of the material.

Having studied geology at university, I never thought that I’d ever be analysing the composition of glass! Recently Dr Maureen Young and I were asked to analyse some glass window panes from Edinburgh Castle to help determine their age. By using a technique called X-ray Florescence (XRF) we can measure the chemical composition of the glass. By identifying specific elements within the material, we can help date the glass, according to the changing manufacturing processes used in Scotland. The panes dated to post 1930’s, indicating the glass had been replaced during repairs to the windows recorded at this time.

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Image 2. Dr Maureen Young using portable XRF on the glass at Edinburgh Castle. Image © Historic Environment Scotland. 

By utilising these newly learnt skills, I’m now conducting my own research project concerning the characterisation and potential climate-change impacts on the Achnabreck rock carvings in Argyll. This site provides some of the best examples of prehistoric rock art in Scotland. By better understanding the composition of the geology at these sites, we can help mitigate the risk to the threats of climate change and help preserve their conditions for future generations.

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Image 3. Image of Achnabreck rock carvings site that is to be analysed. Image © Historic Environment Scotland. 

 

British Science Week 2020: Heritage Science Events

In our second blog post for British Science Week 2020, find out about some of the very exciting heritage science events that are taking place over the next week…

Zoom-In: a closer look at science, British Museum, London

The British museum are offering you the chance to discover how their scientists and conservators unlock the secrets behind the Museum’s collections. The event will mark the 100th anniversary of the opening of a research laboratory at the Museum. As part of celebrations, you will learn about the different techniques that are currently used to monitor and preserve collections and observe the latest technology.  You will also have the opportunity to handle different kinds of raw materials.

Events will be taking place in the Museum’s Great Court all day on Saturday 14th March. Just drop by; there is no need to book beforehand. More details can be found here.

Taking place Thursday 12 March, 9 am- 5 pm. You can book your ticket here.

British Science Week at the Mary Rose, Portsmouth

The Mary Rose Trust has partnered with Zeiss Microscopy to offer visitors an insight into the science used to preserve its collection. You will have the opportunity to see the objects in more detail than ever before and to hear from experts.

Taking place Friday 13- Sunday 15 March. More information available here.

Attend a talk on Bristol’s link with the history of photography and take part in a selection of light and time based experiments, including seeing how the world would appear without a brain. There will also be the opportunity to watch sensitive silver salts become black and white images in a photographic Darkroom.

Events taking place on Saturday 14 March, 1-4 pm. More information here.

The pannotype mystery: using science to research early photographic processes

This year we are again using the wonderful opportunity of British Science Week (6th – 15th March) to showcase brilliant examples of heritage science work being undertaken by NHSF members and across the sector more generally.  We will post new blogs throughout the coming week. 

To launch the series, we have a post written by Ioannis Vasallos, Conservator of photographs and paper at The National Archives, all about the analysis and conservation of rare photographic processes.

The National Archives has an estimate of eight million photographs in its collection. Some of the very early ones can be found on the Design Registers, which contain almost three million British patterns, products’ designs and trademarks from 1839 to 1990s (figure 1). As part of a larger project to understand, conserve and improve access to the Design Registers, Collection Care has been doing research and analysing some rare examples of early photographic processes found amongst them.

Pannotype is an early photographic process invented in 1850s, and used only for a short period of time till the 1880s. Photographs made with this process are rare in collections, and it is therefore exciting to have found 15 pannotypes in a bound volume of the Design Registers (figure 2). These photographs depict designs of ceramic houseware but many of them cannot be accessed due to their deteriorated image layer which has become tacky, and caused other designs to stick on them (figure 3).

A series of analytical techniques were performed in order to understand the composition of the image layer, as well as the rest of the materials that the photographs are made of. Elemental analysis was done with X-Ray Fluorescence spectroscopy (XRF) and showed us the presence of silver particles (figure 4), which confirms the photographic nature of the image. Lead was also detected and seems related to the manufacturing of the cloth support that the pannotypes were placed on. Fourier Transform Infra-Red spectroscopy FTIR analysis identified a natural resin on the photographs whose image layer is degraded, and collodion on others whose image is not affected (figure 5). The analysis helped to combine literature review of historic photographic journals and photographic recipes in order to cross reference the materials that were identified. Finally, the newly acquired Multispectral Imaging system (MSI) was also used to enhance the visibility of the images on the pannotypes whose surface is covered by stuck pieces of paper (figure 6 & 7).

This will now inform the decision making for the conservation of the photographs whose image is degraded and have paper stuck on their surface. The information gained will also enhance the understanding of historic photographic practices helping to preserve similar photographs in other archives and collections.

To find out more about the work of Collection Care you can check the blog of The National Archives at https://blog.nationalarchives.gov.uk/, or you can contact Ioannis Vasallos, Conservator of photographs and paper Ioannis.Vasallos@nationalarchives.gov.uk

NA figure 1
Figure 1: BT 43/67, an open page in a volume from the Design Registers. © The National Archives.
NA Figure 2
Figure 2: BT 43/67, pannotype depicting pottery. © The National Archives.
NA Figure 3
Figure 3: BT 43/67, Group of pannotypes with paper stuck on their surface. © The National Archives.
NA Figure 4
Figure 4: XRF analysis on a pannotype photograph. © The National Archives.
NA Figure 5
Figure 5: Conservation scientist, Lucia Pardo Pereira perform FTIR analysis on a pannotype photograph. © The National Archives.
NA Figure 6
Figure 6: BT 43/67/130678, true colour image captured with MSI. © The National Archives.
NA Figure 7
Figure 7: BT 43/67/130678, infrared reflected (IRR) image captured with MSI. © The National Archives.

Cleaning Modern Oil Paints Project

Tate is the newest recipient of the NHSF Gold Open Access grant for the publication of heritage science research. The grant enabled the publication of the research paper Scientific investigation into the water sensitivity of twentieth century oil paints’, available for free in Microchemical Journal. In this guest post, the paper’s authors tell us more about the Cleaning Modern Oil Paints project.

The Cleaning Modern Oil Paints project (CMOP) is a collaborative European research project, funded through the JPI Heritage Plus programme, which runs from June 2015 – May 2018. The project aims to investigate conservation challenges associated with twentieth and twenty-first century oil paintings in order to ensure that modern oil paintings continue to be fit for display for future generations.

Many unvarnished twentieth and twenty-first century oil paintings are exhibiting unusual water sensitivity. Water sensitivity can be defined as the unwanted removal of pigment and/or original material when a discrete cleaning test is carried out using a dampened cotton swab on the surface of a painting. Water sensitivity is not restricted to a particular oil-paint brand, or artist, and affects a broad range of paintings.

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Winsor & Newton Artist Oil Colour swatches that were studied as part of the microchemical journal paper. Copyright Tate.

Water sensitivity is problematic for conservators, since many of the well-established methods for removing surface dirt (which naturally gathers over time) involves the skilled application of water based cleaning systems.  Since dry-cleaning methods, for example using dry brushes or specialist sponges, are not always particularly effective at removing soiling, water sensitivity can complicate or even prevent effective treatment. This is problematic as accumulated surface dirt can change the appearance of paintings e.g. through altering the saturation, intensity and gloss of paint passages, and can, over the longer term, contribute to other unwanted side-effects relating to ageing and deterioration.

The interdisciplinary CMOP team have been investigating the underlying causes of water sensitivity in modern oil paints. This information has been used to inform the systematic testing and evaluation of selected cleaning systems for use on water sensitive modern oil paintings, with the aim of informing conservators about the risks involved and how to minimise them.

Part of the CMOP research has involved the chemical analysis of a series of naturally aged modern oil paint micro-samples, taken from case study oil paintings and from historic Winsor & Newton (W&N) artists’ oil paint swatches.  The W&N paint swatches were originally produced by the manufacturer for quality control testing, and were subsequently donated to Tate by ColArt UK for research purposes.

W&W Artist Oil Colour swatches studied for the paper, shown in tungsten light (left) and UV light (right). Copyright Tate.

We are pleased to announce that the National Heritage Science Forum has kindly sponsored the Gold Open Access publication of a key CMOP research paper, entitled Scientific investigation into the water sensitivity of twentieth century oil paints, now published in the peer-reviewed Microchemical Journal. This describes an in-depth investigation into the chemical characteristics of water sensitive paint passages, and likely causal factors.

The research at Tate is led by Principal Conservation Scientist Dr Bronwyn Ormsby, with Post-doctoral Researcher Judith Lee, and with the support of Tate’s Collection Care Research. More information on the project and details of the key CMOP project dissemination event; Conference on Modern Oil Paints taking place on 23-25 May 2018, are available on Tate’s website.

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Detail of a case study oil painting analysed as part of the project. Copyright Tate.

 

The paper Scientific investigation into the water sensitivity of twentieth century oil paints is co-authored by Judith Lee and Bronwyn Ormsby of the Tate Conservation Department, Ilaria Bonaduce, Francesca Modugno, Jacopo La Nasa and Klaas Jan van den Berg.

The National Heritage Science Forum provides Gold Open Access grants to help to open up access to heritage science research. This funding is available to employees, students and members of our member organisations – find out more.

Polychromy Revealed: from medieval wood craftsmanship to 3D printing (Paola Ricciardi)

The next post in our British Science Week 2018 series is by guest writer Paola Ricciardi. Paola Ricciardi is the Research Scientist at the Fitzwilliam Museum in Cambridge. She specialises in the non-invasive analysis of polychromy (multi-coloured painting) in cultural heritage objects. In this blog, Paola talks about a workshop on digital imaging, modelling, making and interpretation of 3D cultural heritage objects and their replicas.

The Fitzwilliam Museum holds a small but exceptional collection of medieval wood sculptures, largely polychrome, made across Western Europe c.1300-1550. For the most part extremely fragile, most of the sculptures have never been exhibited and are largely unknown to the public and to academics. Following a 10-month pilot project in 2017, we are currently running a series of activities funded by the Arts and Humanities Impact Fund of the University of Cambridge. These activities are aimed at maximising the impact of the pilot and at defining routes to impact for a large-scale research project – POLYCHROMY REVEALED – which will enable us to investigate, interpret, conserve and display the collection, ultimately transforming it into a resource that can be utilised for teaching, research and public engagement.

Picture of pair of kneeling angels. Copyright Fitzwilliam Museum, Cambridge
Pair of Kneeling Angels, Northern Italy?, 15th Century. Image copyright – The Fitzwilliam Museum, Cambridge.

Three events, running in March-May 2018, are particularly aimed at opening a dialogue with scholars, NGOs, industrial partners and crafts/technology practitioners interested in three-dimensional digital modelling; making; interpretation of; and interaction with, cultural heritage objects and their replicas. We want to assess the state-of-the-art of research in these fields and to establish guidelines for the choice of suitable and affordable solutions, which can then be shared with other museums and cultural institutions. Museum audiences are also involved and will be asked to respond to/interact with the outcomes of the initial phase of activities, in order to inform our methodology and choices for the large-scale project.

The real potential of ever-improving 3D visualisation and ‘making’ technologies is still to be fully explored and as such it is the focus of much attention, as demonstrated for example by a well-attended two-day conference recently held at the British Museum and by the ReACH project, led by the V&A Museum. On 15 March, we ran a half-day workshop in collaboration with the University’s Digital Humanities Network. The workshop brought together experts in a range of topics related to the study of, and interaction with, three-dimensional museum objects, such as 3D sensing, digital modelling, digital and physical making, as well as interpretation and outreach. Speakers and participants discussed the various ways in which digital 3D methods can support and enhance our study and the public’s perception of three-dimensional objects.

Image of panel of speakers. Copyright The Fitzwilliam Museum
Panel speakers. From left to right: Steven Dey, Anais Aguerre, Jonathan Beck and Panel Chair, David Saunders. Image copyright – The Fitzwilliam Museum, Cambridge

Workshop participants were given a demonstration of a structured light scanner which was used to produce models of a selection of polychrome wooden sculptures in the Fitzwilliam Museum collection. They were then asked to work in groups and issue a ‘creative challenge’ to design and produce objects inspired by the original medieval sculptures, based on the 3D models.

Image of Jonathan Beck using a structure light scanner to produce a 3D model of a medieval sculpture. Copyright The Fitzwilliam Museum, Cambridge.
Jonathan Beck using a structured light scanner to produce a 3D model of a medieval sculpture. Image copyright The Fitzwilliam Museum, Cambridge.

The challenge will soon be advertised to members of Cambridge’s Community Workshop MakeSpace and more broadly, and will result in their creations being displayed during a late-night opening of the Fitzwilliam Museum in May. We hope people will feel inspired by the creative challenge and we are very curious to see what they will create!

Image of working together to issue a creative challenge. Copyright The Fitzwilliam Museum, Cambridge
Working together to issue a creative challenge. Image copyright The Fitzwilliam Museum, Cambridge

Find out more about the Polychromy Revealed project

The Fitzwilliam Museum houses the principal collections of art and antiquities of the University of Cambridge, and holds over half a million objects in its care. It leads the University of Cambridge Museums (UCM), a consortium of the eight University Museums and the Cambridge University Botanic Garden, which works in partnership with other Cambridge University collections as well as with museums regionally, nationally and internationally. The University’s collections are a world-class resource for researchers, students and members of the public representing the country’s highest concentration of internationally important collections, all within walking distance of the City Centre. Arts Council England has awarded UCM National Portfolio Organisation status from 2018-2022.

Assessing the light fastness of 16th century Indian paintings (Michela Rampa)

Next in our British Science Week 2018 series, Michela Rampa talks about her student placement at The British Museum, analysing colours in 16th century Indian paintings and assessing light sensitivity. Find out more at The British Museum’s British Science Week event on Saturday 17 March.

Hello, my name is Michela Rampa. I am a student from the University of Rome, La Sapienza, in Italy where I am studying to become a museum scientist. I am currently doing a student placement at The British Museum for my final dissertation. What a fantastic opportunity!

At The British Museum I am based in the Scientific Research Department but also regularly meet with conservators. I am learning how to assess whether museum objects might fade when exposed to light using “microfadeometry”. Microfadeometry is a technique that involves exposing a very small area on an object to an intense light for a short amount of time and recording the colour change on this small area. By comparing the colour change with references, it is possible estimate whether the object is sensitive to light or not.

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Examination of a 16th century Indian painting

Why is it so important to assess the lightfastness of museum objects? Many museum objects are light sensitive, for instance: watercolours, prints or textiles. We cannot stop fading from occurring when these objects are displayed, but we can ensure that light-sensitive objects fade so slowly that they will be seen by countless generations of visitors to the Museum in the future. Knowing if an object is likely to fade when exposed to light helps curators to decide how long  it can be displayed and under which conditions. For example, microfading tests carried out on Hokusai’s iconic prints ‘The Great Wave’ and ‘Red Fuji’ last year showed that these should be displayed using dim light for a short amount of time (read about it here).

Michela Rampa BM image 2
Experimental Technical Imaging laboratory in The British Museum

I am currently investigating the lightfastness of some Indian paintings, which will go on display in the new Albukhary Foundation Galleries of the Islamic World at the end of this year. One of them is a very colourful Hamzanama painting made in 1500. (Hamzanama is a series of manuscripts, most of them illustrated, that narrate the legendary deeds of Amir Hamza, the uncle of prophet Muhammad). It is very valuable and I have identified at least 13 different colours on it! I expected that most colours on this painting were produced using mineral pigments and therefore would not fade. However, I am discovering that, on the contrary, several colours, such as green, are light sensitive! I am hoping to perform more analysis to find out why these colours are affected by light. Work in progress!

In the meantime, if you want to know more about the work scientists do at the British Museum, please come and find me and the rest of the Scientific Research team at our annual event ZOOM IN: a closer look at science on Saturday 17 March 2018, 10.00 – 16.00, in the Great Court at The British Museum. Learn about all of the different techniques that are used to analyse the Museum’s collections, handle different kinds of raw materials and see the latest behind-the-scenes technology in action. This is a FREE event too!

Michela can be contacted by email and on LinkedIn. You can find out more about the upcoming Albukhary Foundation Galleries of the Islamic World on The British Museum website.