STORMLAMP – A research project measuring the impact of waves on historic rock mounted lighthouses

Author: Eve Allen

STORMLAMP is a research project that monitors and measures the impact of waves on the structural performance of lighthouses.

The project began in May 2016 and has focused on six lighthouses spread across the British Isles. These lighthouses were selected due to the particularly extreme wave environments that surround them and their unique structural elements or operational issues.

The STORMLAMP project is a great example of how engineering can benefit communities, trade and heritage. Historic rock-mounted lighthouses continue to play an essential role in the safe navigation around perilous reefs. However, their longevity is threatened by the battering of waves which may be set to increase with climate change. Virtual navigational aids such as GPS are fallible, and reliance on them can be disastrous. Mariners will continue to need lighthouses as these physical visual aids are strategically placed to assist navigation. The loss of any reef lighthouse will be incalculable in terms of safety, commerce and heritage.

A person stood on a helipad by the coast flies a drone.
James Bassitt (University of Exeter) operating Phantom drone from helipad at Fastnet Lighthouse

This complex project requires a unique combination of skills available from three UK universities: University College London (UCL), University of Exeter and University of Plymouth.

Three people sit in knee deep water in the COAST laboratory simulator. A model lighthouse at scale 1:40 is in the foreground.
Alison Raby (University of Plymouth), Dassa Dassanayake (University of Plymouth), Peter Dobson (Trinity House) in the COAST Laboratory at University of Plymouth.

University of Plymouth works on predicting extreme storm conditions for offshore rock lighthouses using long-term metoceanic data. Plymouth also carries out physical tests using scale models of lighthouses and uses Computational Fluid Dynamics modelling to identify how wave loading interacts with these rock structures. University of Exeter accesses the lighthouses for installing monitoring systems and performing modal analysis in order to identify the structural characteristics of the lighthouses. Finally, UCL uses the data produced from the other two universities to carry out detailed structural analysis to assess how resilient the lighthouses are under extreme wave impacts.

One of the lighthouses STORMLAMP is investigating is Wolf Rock, which lies about 8 miles from Land’s End. The tower is built upon a rocky pinnacle which is completely obscured at high tide and was selected for long-term monitoring by STORMLAMP due to the unbroken Atlantic waves it encounters. It’s one of the larger towers in the project at 41m and was built in 1869. As with many of the lighthouses access is via helicopter, landing on the helideck at the top of the tower. Modal testing took place in 18 July 2016 and James Bassitt, based at University of Exeter took some fantastic footage from the helicopter flight to Wolf Rock.

A sequence of five images show tests conducted on the 1:40 scale model lighthouse.
Wave impact tests with the 1:40 scale model of Wolf Rock lighthouse in the COAST Laboratory at the University of Plymouth

As the four-year project comes to a close, a final workshop is planned for May 2020 to showcase the STORMLAMP research to a wider audience. The workshop will involve presentations on lighthouse research and relevant areas from academics, heritage professionals and industry stakeholders, as well as discussions on future directions for related research.

To find out more about the project and the lighthouses STORMLAMP has been working with, visit the  website. There are plenty more pictures of the team in action and details of our partners and of course the lighthouses themselves.

https://stormlamp.org.uk/ 

@stormlamp_edu

Excavating the Rooswijk … virtually!

The next blog in our British Science Week 2020 series come from MSDS Marine, a Marine and Coastal Contractor specialising in the management, execution and support of archaeological projects in the marine environment. 

The Rooswijk was a Dutch East India Company vessel which sank on the treacherous Goodwin Sands, off Kent, in January 1740. The ship was outward-bound for Batavia (modern-day Jakarta) with trade goods. The site is now protected by the Protection of Wrecks Act 1973. The ship’s remains are owned by the Dutch Government; however, the UK government is responsible for managing shipwrecks in British waters, therefore both countries work closely together to manage and protect the wreck site.

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Figure 1. Clockwise from top left: Multibeam image showing the main area of wreckage on the Rooswijk, A diver excavating in 2018. Lead project Conservator Angela Middleton examining a concreted chest from the side. A screenshot of the Rooswijk virtual trail.

A two-year archaeological excavation project was undertaken between 2017 and 2018 due to the site being at high risk of loss through environmental changes and unauthorised diving. Wrecks such as the Rooswijk are part of the shared cultural maritime heritage across Europe and it’s important that cultural heritage agencies are able to work together to ensure that sites like this are protected, researched, understood and appreciated by all. The project involves an international team led by The Cultural Heritage Agency of the Netherlands (RCE) in partnership with Historic England. MSDS Marine are the UK Project Managers for the project.

In 2019 MSDS Marine, working with ArtasMedia, created a virtual tour of the site: https://msdsmarine.com/projects/dive-trails/rooswijk-virtual-trail/. Now the projects archaeologists are working with the μ-VIS X-ray Imaging Centre at the University of Southampton to further excavate the site virtually!

A number of stacks of coins were found during the excavation. Some of these were carefully separated by the conservators from the Investigative Science Team at Historic England (Figure 2). Some could not be separated.

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Figure 2. An MSDS Marine conservator separating coins from the Rooswijk in the Historic England laboratory.

A number of stacks were then sent to the μ-VIS X-ray Imaging Centre (www.muvis.org) at the University of Southampton to be micro-CT scanned. X-ray micro-Computed Tomography (µ-CT) scanning is a volumetric scanning technique, which enables us to virtually cut open materials to look inside with micrometre spatial resolution, while preserving the condition of the object we are scanning. During the scan, the object is rotated 360 degrees as thousands of 2D X-ray projection images are acquired. These 2D images are then reconstructed into a three-dimensional volume, which is made up of cubic pixels with intensities related to the amount of x-ray energy absorbed at that point.

We used the custom walk-in scanner (the Hutch) at the µ-VIS X-ray Imaging Centre to scan the concreted coins, which were stacked in sealed tubes to prevent excessive drying during the scanning process (Figure 3).

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Figure 3. Concreted coins mounted for µ-CT scanning within the custom Nikon/X-tek 450/225 kVp Hutch at the µ-VIS X-ray Imaging Centre, University of Southampton

The digital reconstructed volumes were then sent to MSDS Marine, where myVGL software (Volume Graphics GmbH, Germany) was used to manipulate the volume data, so that the individual faces inside the stacks could be seen (Figure 4). These coin faces have not been seen since they were packed into chests for the voyage almost 280 years ago.

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Figure 4. A Rider coin from 1739 that has been virtually separated from a large coin stack.

The coin face slice images will be sent to Jan Pelsdonk, the projects numismatist, for identification and will contribute to the understanding of the wreck.

The application of scientific techniques like CT scanning and digital model processing have contributed hugely to the understanding of underwater heritage, and continue to offer new and exciting ways of investigating these important cultural sites.

Phoebe Ronn, MSDS Marine Phoebe@MSDSMarine.co.uk

www.MSDSMarine.co.uk

Katy Rankin, µ-VIS X-ray Imaging Centre, University of Southampton, k.rankin@soton.ac.uk

www.southampton.ac.uk/muvis

Unlocking the archive through scientific analysis: heritage science research at The National Archives

Author: Natalie Brown Senior Conservation Manger – Engagement

The purpose of the Collection Care Department at The National Archives is to ensure access to our collection through its long-term preservation and display. Through established and innovative programmes of environmental management, conservation treatment, and research initiatives we aim to prolong the life of our collection for future generations and enhance the artefactual value of archival collections beyond what is written on the page. As a department crouched in an Independent Research Organisation (IRO) we are able to co-create applied and interpretive heritage science projects that enable us to investigate the material composition and physical state of the collection, study how art materials were used throughout history, model how materials will degrade, and address changing conservation practices. Below are two projects highlighting how we do this in practice.

ArcHives

The aim of ArcHives is to use wax as a bimolecular archive to inform upon the geographic origin of beeswax (and bees); the changing diversity of the hive microbiome in modern; and historical beeswax and the DNA of individuals associated with the production of the legal documents trapped in kneaded wax. The National Archives holds over 250,000 seals dating from the 11th to the 20th Century and this project will allow us to explore our wax seal collection on a biomolecular level. We hope to gain knowledge around the material composition of wax seals in our collection which will allow for a deeper understanding of the physical and chemical processes responsible for their ageing and degradation. The four-year project is led by an international cross-disciplinary team of molecular biologists, palaeoproteomicists, heritage scientists, historians and chemists. Lora Angelova PhD, the Head of Conservation: Research and Engagement, is an advisor on this project.

A manuscript from 13th century with 56 wax seals attached.
Reference: DL 27/270. A document created in 1217-32 with 56 attached wax seals, housed at The National Archives. Image courtesy of The National Archives.

AI for DigiLab

AI for DigiLab aims to combine artificial intelligence and advanced imaging techniques to analyse historic map collections. The project is a collaboration between The National Archives, Nottingham Trent University – ISAAC group, Yale, Getty GCI, and University of Southern Maine- Osher Map Library. The National Archives holds around six million maps ranging from the 14th to 20th Century, some of which are hand-drawn and colourfully painted. Image techniques, such as x-ray fluorescence scanning or multispectral imaging, are useful to investigate the materials, such as pigments, inks and dyes, used by the mapmakers. In the project, algorithms will be used to analyse the large datasets produced from these imaging techniques to determine the materials present in the maps. We hope that by applying big data analysis to international historic map collections we can shed light on maps production context, the trade of the materials, and possible influences between the metropolis, the colonies and across media. Lucia Pereira-Pardo PhD, Senior Conservation Scientist is a co-investigator on this project.

Four variations on an image of a map of Ulster taken with multispectral imaging.
Multispectral imaging of a map of Ulster by Richard Bartlett (1603) with pigment and dye references taken by Lucia Pereira-Pardo. Image courtesy of The National Archives.

Identifying Lauder’s pigments using XRF

The latest blog post in our British Science Week 2020 series is written by Clara Gonzalez, a post graduate student studying for an MLitt in Technical Art History at the University of Glasgow. She is currently doing a work placement with the Conservation Department of the National Galleries of Scotland.

The National Galleries of Scotland (NGS) and the Technical Art History Group, Glasgow University (TAHG) are working together on a systematic technical study of Christ Teacheth Humility by Robert Scott Lauder (1803-1869).

In 1847, Lauder submitted this painting to a competition organised to provide works of art for the Houses of Parliament. Lauder did not win, but the painting gained him public recognition. In 1849 it was acquired by NGS, becoming part of the early foundation of the collection.

The vivid palette used in the painting reveals Lauder’s interest in the effects of colour, inspired by Venetian 16th century painters such as Titian. At the time Lauder was working, traditional pigments were still in use, and artists experimented with pigments made from newly discovered compounds which were also commercially available.

A well-established analytical method for  the technical examination of paintings (specifically the identification of inorganic components of artists’ materials) is X-ray fluorescence (XRF). XRF is a non-destructive, non-invasive analytical tool. The TAHG XRF analyser is a portable, handheld Niton XL3t. This portability is particularly suitable for examination of this work due to its dimensions (2.5 x 3.7m) and offsite location in the gallery store. Using XRF, we will characterise inorganic elements present. In combination with other techniques (such as paint sampling) this analysis will be used to build a holistic picture of materials used, including pigments, and to gain an understanding of Lauder’s material choices for this painting, the most ambitious project of his career.

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XRF analyser during analysis 1.
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XRF analyser during analysis 2.
Person examining a small scanner mounted on a tripod, in front of a large painting.
Examining the XRF analyser in front of the painting.

What is a Geospatial Survey Technician Apprenticeship?

The next blog post in our British Science Week 2020 series is written by Elizabeth Stephens from Historic England. 

Key facts about the Geospatial Survey Technician Apprenticeship –

  • A new apprenticeship standard approved for delivery in February 2018
  • Level 3 – this is equivalent to an A level
  • Based within the Construction route
  • Typically lasts 2 years
  • Time split with 80% working within a company and 20% off site training

My experience as an apprentice

I am now 16 months into my Geospatial Survey Technician Apprenticeship at Historic England. A lot has happened in that time. Projects undertaken have included coins, caves, churches and castles, all very different and all very interesting.

Historic England

I am employed by Historic England in the Geospatial Survey team. It’s a great place to work and the sites and objects I get to see are amazing. The support I receive at Historic England is excellent, there’s always someone to talk to, explain a piece of equipment or give advice.

My role at Historic England in one sentence

Using a range of equipment and software including different scanners and photogrammetry to survey building and objects, often generating 3D models that can be used to aid conservation work, monitor the structure, record, or as a learning tool.

Leeds College of Building

I spend around 20% of my time at Leeds College of Building where I have been learning lots. This year’s units have included Topographic Surveying and Geographical Information Systems. The units this year have been really interesting and very relevant. The first year was more background theory but this year has been more connected to what I do at work and has a bigger emphasis on the practical application.

Drone flying

I have been lucky enough to be part of the first group of colleagues at Historic England to undergo training and receive our PfCO (Permission for Commercial Operations).  I am now able to fly a drone to capture images of different sites that are used to complete surveys.

Photogrammetry and laser scanning

Within my work at Historic England we often carry out laser scanning at sites to capture the shape and condition of a building or object. The laser scans are joined together when back in the office and produce a 3D model of the building or object. We use a range of scanners including mobile, hand held systems.

Photogrammetry is also used which involves taking many overlapping images that are then processed to produce a 3D model.

These methods can be combined into a ‘reality capture’ model combining the superior images from the photogrammetry and the geometry from the laser scanning. The laser scanning produces the framework that is then wrapped in the images.

Why apprenticeships are fantastic

  • Gain qualifications while earning
  • A chance to meet others within the industry for future contacts
  • Support and guidance from everyone in the organisation
  • Learning a wide range of transferable skills
  • Practical experience working within the sector
  • A chance to change career and learn a new skill set
Historic England 1
Shire Ditch.
Historic England 2
Longthorpe Tower.

Historic England 3

Historic England 4
Nottingham Caves.
Historic England 5
Nottingham Caves.
Historic England 6
PrimeScan- Whitby Objects

Vanishing Heritage: Digital Documentation at Kilmartin Glen

This is the last blog post from Historic Environment Scotland in our current British Science Week 2020 series. 

Written by Bonnie (Nicole Burton) 

Since starting my Trainee position in August with Historic Environment Scotland, I have worked with the Digital Documentation team on various sites, ranging from Neolithic chambered cairns at Kilmartin Glen to Iron Age Brochs at the Isles of Lewis.

These projects were undertaken as part of the Rae Project, involving both the Digital Documentation and Digital Innovation team at the Engine Shed. The focus of the Rae Project is to digitally record all historic sites in Historic Environment Scotland’s care across Scotland, as well as their large array of collection items. The aim of this project is to have a full database for sites that are vulnerable or at-risk, using the datasets for management and monitoring.

The largest project I have been involved with was at Kilmartin Glen in August. The teams spent two weeks digitally documenting 15 sites and 30 collections items. Kilmartin Glen is located in Argyll and Bute, western Scotland and is enriched with prehistoric monuments and historical sites.

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Laser scanning at Kilmartin Glen. © Historic Environment Scotland.

The documented sites range from chambered cairns, historic buildings, rock art, stone circles and stone artefacts. After the initial documentation had taken place the processing of the data had to be carried out using a wide range of software packages to create accurate 3D models that can be shared with the public [https://sketchfab.com/3d-models/cairnbaan-west-kilmartin-glen-7b63521779c440c19bd7079ba2d5842f].

Terrestrial laser scanning

Laser scanning is a straight forward process: the instrument has a rotating laser beam that reflects off a given surface, creating billions of points in 3D space representing the shape of a surface. Whilst scanning, multiple factors are needed to be taken into consideration, including the need for overlapping scans is to ensure a complete 3D model can be created, the terrain and environmental conditions. Our team uses a variety of laser scanners– some used for overview scans and others for the finer detail.

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Using a laser scanning to digital document cup and ring marks at Achnabreck. © Historic Environment Scotland.

Photogrammetry

Photogrammetry is a technique of using a camera to take overlapping photographs ensuring all areas of the subject has been captured to create a 3D model. While simple in theory, the better the pictures, the better the model, so we make sure to use a colour checker and a good lens.

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Digital Innovation trainee Kieran Young using Photogrammetry at Achnabreck. © Historic Environment Scotland.

Heritage in Scotland is becoming more and more at risk due to increased flooding and the changing climate. The work our team is doing not only at Kilmartin Glen but on other sites like Skara Brae is aiding in the management and monitoring of significant cultural heritage.

If you use twitter and would like to keep up to date with our projects, then follow the #Raeproject and @Burton1495

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

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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.
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Figure 3: BT 43/67, Group of pannotypes with paper stuck on their surface. © The National Archives.
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Figure 4: XRF analysis on a pannotype photograph. © The National Archives.
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Figure 5: Conservation scientist, Lucia Pardo Pereira perform FTIR analysis on a pannotype photograph. © The National Archives.
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Figure 6: BT 43/67/130678, true colour image captured with MSI. © The National Archives.
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Figure 7: BT 43/67/130678, infrared reflected (IRR) image captured with MSI. © The National Archives.