Eight million photographs: how can science help? – Jacquie Moon, the National Archives

As part of British Science Week 2017 the National Heritage Science Forum is featuring blog posts from heritage scientists from across its member organisations. This year’s theme is ‘sharing heritage science’, and the blogs over the rest of the week will give an insight into the many different forms that heritage science can takes, as well as some of the different ways of getting involved.

Jacqueline Moon is the Senior Conservator for Public and Academic Engagement at the National Archives. She specialises in the conservation of photographs. In this blog, Jacqueline describes how she is using science to care for the photographic collection with the help of volunteers.

The National Archives’ collection includes approximately eight million photographs. The subjects are varied, and include Victorian and Edwardian photographs from the 1850s; of Eccles cakes, circus performers with boa constrictors, ‘the oldest lady in bed’, children acting out barber shop scenes and the Titanic. Later collections include the more serious Operation Sandstone, a unique survey of the British coastline which began in 1947 to help NATO forces plan a re-invasion in case the country was taken over by communist forces.

Their sensitivity to moisture and pollutants poses unique challenges for preservation and conservation. To understand these collections better, the Collection Care department at The National Archives’ is doing a survey with the help of volunteers, who have been trained to identify photographs and understand their deterioration. Their observations are helping us prioritise conservation projects, improve storage and use science to build a more accurate picture of the collection. Without their help it would be impossible.

15b_TNA_Figure 1. Cross section of SG photo - JM.jpg
A cross-section of a silver gelatine photograph on fibre-based paper

Silver gelatine photographs are prone to mirroring (a bluish reflective sheen seen in the shadow areas), yellowing and fading. This is because of changes to the image silver which can be caused by high relative humidity, pollutants or poor processing. Experts claim to be able to look at a deteriorated photograph and tell the causes; an image affected by high humidity would have a more yellowed appearance but an image which has been poorly processed would look more orange brown.  

Top: A well processed test photograph partially aged and the same photograph at x150,000. Below: A poorly processed test photograph partially aged and the same photograph at x150,000.

The photograph conservator at The National Archives undertook research into the deterioration of silver gelatine photographs, the commonest type in the collection, to find out if a simple colour measurement by non specialists could help make conservation decisions, such as prioritising certain items for cool storage and selecting others for the exhibitions and the loans programme. A number of scientific techniques were used to study a set of laboratory made and historical photographs. The techniques included spectrophotometry (a method for quantifying colour), transmission electron microscopy (effectively a microscope but instead of light and lenses it has electrons and electromagnetic fields) and spot tests to test for impurities 

15b_TNA_Figure 3. Taking colour measurements of yellowed historical photographs - JM.JPG
Taking colour measurements of a series of sample photographs

The colour measurements showed that photographs affected by poor processing had red and purple hues, whilst transmission electron microscopy showed they had clumped image silver; those affected by high relative humidity were more yellow but had lots of spherical silver particles, called colloidal silver (see image 2)

The next steps are to prove this on a larger scale so it could be used more widely; testing records affected by yellowing using information gathered during the survey. Volunteers will be trained to collect and interpret the colour data and the results will be publicised in due course. If you’d like to read more about how we care for the photographic collection at The National Archives, you can read our blog here.

Private Space on Public View: Dust Monitoring for the Eduardo Paolozzi studio at the National Galleries of Scotland

As part of British Science Week 2017, the National Heritage Science Forum is once again featuring blog posts from heritage scientists from across its member organisations. This year’s theme is ‘sharing heritage science’ and the blogs over the rest of the week will give an insight into the many different forms that heritage science can takes, as well as some of the different ways of getting involved.

After yesterday’s post about the London shipwreck, today’s article looks at Arielle Juler’s dust monitoring project for the Eduardo Paolozzi studio at the National Galleries of Scotland…

15_AJ_NGS IMG_20170310_092116998.jpg
View into the Eduardo Paolozzi studio from the visitor barrier

Arielle Juler is currently undertaking a Preventive Conservation MA degree with Northumbria University. As part of her dissertation research, she is looking into the preventive conservation plans and methodology available for the preservation of artists’ studios on public display within gallery spaces. Using the methodology established by the National Trust for dust monitoring in historic houses, she’s conducting a low-technology dust monitoring project. The monitoring method uses slide mount frames and clear adhesive labels to trap dust as it falls on the slide. The rate of deposition is then measured against a graph paper and percentage coverage can be estimated. The percentage estimations can be compared and inform the rates of dust deposition and how/where dirt enters the studio space.  

15_AJ_NGS Trap 2
Dust trap in situ within the Eduardo Paolozzi studio
15_AJ_NGS IMG_20170310_091134692
Arielle Juler examines dust slide within the Eduardo Paolozzi studio

The dust monitoring project started in September 2016 and is ongoing through April 2017. The project will provide baseline information on the rates and levels of dust deposition on the objects within the studio space. Currently it is not known how quickly the studio becomes dusty or where the dirt is entering the studio space.

The National Galleries of Scotland will be able to use the data gathered from the monitoring project to establish a conservation plan and cleaning schedule for the studio space. This will in turn assist in the preservation of the artist’s materials and ephemera on public display.

Contact the Conservation department at the National Galleries of Scotland: conservation@nationalgalleries.org 

Historic England – Conservation of artefacts from the ‘London’ shipwreck

As part of British Science Week 2017, the National Heritage Science Forum is once again featuring blog posts from heritage scientists from across its member organisations. This year’s theme is ‘sharing heritage science’ and the blogs over the rest of the week will give an insight into the many different forms that heritage science can takes, as well as some of the different ways of getting involved.

Next up is a post by Dr. Eric Nordgren of Historic England, talking about the conservation of artefacts on the wreck of the 1665 London ship…

The London was a Royal Navy warship that sank in the Thames Estuary following an explosion in 1665. A program of work to better understand this protected shipwreck has been underway since 2014, resulting in surface recovery of exposed objects and in two seasons of underwater excavation and recovery of hundreds of artefacts made of wood, leather, rope, ceramic, glass, iron, copper and lead. The LondonWreck1665 project is a collaboration between the protected wreck licensee, maritime archaeologists from Cotswold Archaeology, scientists and conservators at Historic England’s Fort Cumberland site in Portsmouth and the Southend Museums Service, where the artefacts and scientific data will be deposited.

The goals of conservators working on the London material are to assess the condition of the artefacts and apply investigative and remedial conservation techniques to make them as stable as possible for study and display at Southend Museums while learning as much as possible about the materials they were made from, how they were produced, and their working life on-board ship. The conservation process offers lots of opportunities to collaborate with specialist scientists to gain information such as the species of wood used to make artefacts such as musket powder cartridge bottles, the type of fibres used in rigging and cordage or the elemental composition of glass and metal finds. All of this adds to our knowledge of 17th Century seafaring and life on-board the London in particular.

All materials change and as conservators we try to understand these changes and slow them down. Iron artefacts for example often develop a thick coating of rust and marine growth called ‘concretion’ that can hide their true shape. Conservators use X-radiography to get a closer look inside the objects. These X-rays help conservators plan micro-excavation of concreted artefacts in the laboratory or can sometimes reveal the shape of objects which are no longer preserved.

Photo (left) and digital X-radiograph (right) of an iron artefact from the wreck of the London. The object is covered by rust and concretion but radiography allows conservators to look inside and see the original size of the iron ring and how much metal still remains. (Images: Historic England 2017)


Conservators working on London artefacts use a variety of scientific principles and analytical techniques in their daily work. An example is the monitoring of salt removal (or desalination). Both organic (wood, leather) and inorganic (ceramics, glass, metal) materials can be damaged if allowed to dry out while they still contain soluble salts such as sodium chloride. Artefacts are soaked in baths of distilled water which allows salts to diffuse out, allowing them to be safely dried.

Some objects such as a cast iron cannon ball can’t be desalinated effectively using distilled water alone. For marine iron, 0.5 Molar sodium hydroxide solution in distilled water (pH 13.5) is used to extract chlorides more effectively. The concentration of chloride salts measured in parts per million (ppm) in the desalination bath is monitored weekly, allowing us to track chloride release, determine when the bath needs changing and when the treatment is finished (normally when very low levels of chloride are detected in solution).

Graph showing concentration of chloride extracted (in parts per million) from a cast iron cannonball from the London into a sodium hydroxide (NaOH) desalination solution over 50 days. The concentration reaches 550 ppm after about 35 days, indicating it is time for a fresh desalination bath. (Images: Historic England 2017)

The Historic England conservation team working on the London at Fort Cumberland, Portsmouth includes Angela Middleton and Eric Nordgren.

Find out more about the London by following #LondonWreck1665!

SEAHA Mobile Heritage Lab – Public Engagement at Hellens Manor

As part of British Science Week 2017 the National Heritage Science Forum is once again featuring blog posts from heritage scientists from across its member organisations. This year’s theme is ‘sharing heritage science’ – the blogs over the rest of the week will give an insight into the many different forms that heritage science can takes, as well as some of the different ways of getting involved.

Following on from yesterday’s post about events at the British Museum, Josep Grau-Bové blogs about a recent event at Hellens Manor…

State of the art scientific research met one of the oldest houses in the country on Saturday 11th March. The foundations of Hellens Manor in Herefordshire date from the 11th century, and it is often said to be one of the oldest dwellings in England. Its collections of paintings, textiles, furniture, armoury and household objects tell the story of the last five centuries.

Every year, SEAHA students spend a week in the house, using scientific research to support the conservation of the building and its collection. To celebrate the Science Week, which this year coincided with the annual field trip, SEAHA students displayed their research in action in the house, and visitors had the opportunity to see first-hand how science can be used in historic buildings.

The purpose of the activity was to demonstrate how scientific research can have very practical outcomes that support conservation. SEAHA students demonstrated three interactive experiments:

  • Firstly, visitors used thermal imaging to locate moisture on the walls of the building.
Thermal imaging was used to analyse indoor microenvironments, but visitors also enjoyed taking some thermal portraits.
  • Secondly, they analysed insects and pests under the microscope, and learned about the basics of pest management.
  • Finally, they had the opportunity of using imaging techniques to explore underdrawings in a painting.
A SEAHA student uses a modified camera to capture reflected IR from a mock-Fayum painting during one of the demonstrations.

Visitors also got a chance to see the SEAHA Mobile Lab, where students offered a general introduction to the main themes of Heritage Science.

The manor is well known in the county as the host of a diverse cultural programme. Through this activity, the usual visitors to Hellens Manor – local communities of Much Marcle, the surrounding area – could see a familiar collection under a totally different light. The familiarity of the visitors with the site led to very interesting conversations with students, which often helped them see their research from a different perspective.

SEAHA organises frequent Public Engagement activities on historic sites. For more information, follow us on Twitter @seahacdt and through our website.

Zoom In – A closer look at science at the British Museum

As part of British Science Week 2017 the National Heritage Science Forum is again featuring blog posts from heritage scientists from across its member organisations. This year’s theme is ‘sharing heritage science’ and the blogs over the rest of the week will give an insight into the many different forms that heritage science can take, as well as some of the different ways of getting involved.

We start, today, with Peter Mc Elhinney’s summary of British Science Week events that will take place at the British Museum, including this afternoon’s Facebook Live event…

This week, the British Museum’s scientists come out from behind the scenes for a free event that offers visitors the chance to take a look at heritage science in the Museum. Visitors will get the chance to learn about the techniques that are used to monitor and care for the Museum’s collections, and see the latest behind-the-scenes technology in action.

  • Tune in NOW(!) for a Facebook Live event, to see some of the less portable analytical equipment demonstrated in action from within the World Conservation and Exhibitions Centre. The session will offer a rare opportunity to gain a sense of the research capabilities of this new facility. The Museum’s Facebook followers can comment and ask questions during the live session, or view the recording later and leave comments or questions on the Museum’s Facebook page thereafter.
    To watch the broadcast or subscribe to the Museum’s exciting future live events, visit the British Museum’s Facebook page on your desktop, laptop, tablet or phone.
  • On Saturday 18th March, drop by the British Museum for ‘Zoom-In’, a day of hands-on sessions in the Great Court (10 am to 4 pm). Visitors will be able to handle the raw materials used to make museum objects. For more information, please visit the British Museum events page.

The events are aimed at younger, budding heritage scientists, but visitors of all ages and interests will enjoy meeting with the museum’s industry leading scientists and conservators, asking questions and learning about the fascinating research going on within the British Museum.

13_BM_Image 1
Scientist Dan O’Flynn at work in the X-Radiography Suite. Dan will be demonstrating X-radiography and CT-scanning as part of the Facebook live event.
13_BM_Image 2
Scientist Harriet White at work on the Scanning Electron Microscope (SEM) – she will be doing an SEM demonstration during today’s Facebook live event.


Filling the Gaps #10 Increasing Access to Tools and Knowledge

The tenth and last part of our Filling the Gaps survey is now up!

Since September this year, we have been collecting information about current or recent research, on topics highlighted by the National Heritage Science Strategy as gaps in knowledge and practice.

The 10th survey focuses on increasing access to tools and knowledge amongst and beyond the heritage science community.

To achieve this, the Strategy’s evidence report highlighted four priority goals:

  • improved awareness of existing techniques
  • better access to analytical facilities, including portable equipment
  • increased range of facilities for the analysis of organic materials
  • the need for a directory of services available, type, costs and funding opportunities

Want to help us ‘fill in the gaps’? You can add your knowledge of research or initiatives addressing the above via our survey form. The projects in question can be ongoing or completed, published or unpublished, the only criteria is that they started in or after 2009. Feel free to provide as much or as little information as you want – but the more you can contribute, the better a resource we can create.

The other topics in the survey series are still open:

  1. Understanding decay mechanisms and rates of decay of movable items
  2. Understanding decay mechanisms and rates of decay of built historic environment
  3. Understanding decay mechanisms and rates of decay of archaeology
  4. Understanding the material behaviour of modern materials (movable items)
  5. Understanding the material behaviour of modern materials (built historic environment)
  6. Creating appropriate environments
  7. Adapting to climate change
  8. Improving practice in the assessment and monitoring of state
  9. Improving practice: past present and future conservation treatments

Many thanks for your contributions so far – please share this link widely so we may create a useful resource!

National Heritage Science Forum

Filling the Gaps #9 Past, Present and Future Conservation Treatments

The ninth Filling the Gaps survey is now online, investigating existing reviews of current conservation practices for better long-term planning and research into potential future techniques.

The National Heritage Science Strategy evidence report highlighted a need for additional research in the following areas:

  1. Revisiting current treatment options and operational procedures to:
    • assess the cost/benefit of existing treatment methods; ineffective treatments can lead to higher conservation and collection management costs in the future
    • ascertain whether anecdotal reporting of the deterioration of conserved objects are justified (e.g. recent questions about the long-term stability of PEG treated wood)
    • ensure that current treatments do not unintentionally reduce information retrieval; the information that can be recovered from heritage assets now is greater than when some treatments were devised (such as DNA from natural history collections, organic residues from ceramics)
    • consider the impact of standard procedures – for example, dusting and cleaning objects on display, or washing of archaeological finds
    • evaluate whether current techniques will still be appropriate in a changing climate.
  2. Further development of the following:
    • nanotechnology (for example, nanodeposition of calcium hydroxide for consolidation of wall paintings)
    • biotechnology (further testing of microbial cleaning and consolidation of stone)
    • improved methods of digitisation of paper and audio-visual material
    • further development of digital x-radiography
    • research into new coatings, particularly for outdoor metals (such as superhydrophobic materials)
    • laser cleaning (and its use on a larger range of materials)
    • treatments for modern materials
    • re-scaling of existing treatments, to be available at larger (i.e. laser cleaning) or smaller or more portable (i.e. mass de-acidification) scales
  3. Research into new materials for use for conservation purposes, including:
    • lightweight strong materials, i.e. high tensile strength thread for displaying beadwork
    • new absorbent materials to control pollution and moisture
    • inert materials that can be used in treatment to improve the retention of shape (for example in all stages of the conservation of waterlogged archaeological leather)

If you know of any research, completed or underway, published or unpublished, touching on the above topics, please let us know by filling in our online form. Our only requirement is that the research started in or after 2009. No need to fill in all the fields – but the more information you can provide, the more useful a resource we can create for the heritage science community.

Many thanks for your contribution – please don’t hesitate to share this link!

National Heritage Science Forum