How does Analytical Chemistry Support Preservation in Cultural Heritage Studies?

An interview with Dr. Fenella G. France, to introduce the ideas behind the Plenary Lecture to be given at Pittcon 2019.

What is a Cultural Heritage Scientist and what are the challenges they face?

Heritage Science is the new term to encompass all the cross-disciplinary scientific research of cultural heritage – all the different types of institutions, (museums, art galleries, libraries, archives) and the range of types of heritage materials – from immovable sculptures, archaeology, buildings, to books, paintings etc.

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Most of the time, we don’t know what has happened to a specific object in its past. Our work involves forensically remapping and uncovering what might have happened to the object; characterizing from specific analyses and defining the degradation mechanisms for that specific material. Since we are not usually able to sample from the heritage object, we have created a database and selection of materials for creating reference samples to recreate, predict change from a specific treatment or the environment, and then finding the best way to stabilize that material/object, without creating more challenges for scientists in the future.

It’s not just one material we are working with, but rather we need to have expertise and experience with many different materials. This includes, but is not limited to: paper (cellulose), protein, parchment, glues, wool, glass, metal, pigments, inks, sound recordings, modern polymers, ceramics, fibers, modern storage materials - the list is very broad and diverse.

Another challenge is that often useful information is obtained from destructive testing techniques, so much of the development in my lab and the field over the past 10+ years is expanding our capability for non-invasive techniques that cause no harm to collection items. We are the ones in the trade show asking manufacturers weird questions about a new and novel way of using some technique, and always for open-architecture instrumentation that allow us to analyse from the surface, non-invasively, of objects that are not usually small or easily manipulated.

How are cultural heritage and conservation science linked?Our work will be explored in my Plenary Lecture at Pittcon 2019, where I will explain through examples of what we do and the challenges we face. By sharing my story at Pittcon, I hope engage and encourage new colleagues in collaborating and sharing their expertise with us to preserve our cultural heritage.

Cultural heritage covers the broader set of activities, preventive, management, cross-disciplinary collaborations between related fields. Conservation science traditionally supported conservation of objects within heritage institution. Often this is to characterize the state of the object, how might a treatment impact it or how can the paper/parchment/glass etc be stabilized. Therefore, cultural heritage and conservation science are fully connected, but heritage science as considered a broader all encompassing term.

How can science support historians in revealing the truth about our past and historic events?

The limit, from what I have seen, is often only restricted by the question of the historian/researcher. Imaging can show evidence of creation techniques. For example, some imaging techniques can identify the colorants in an object and tell us if it is from the expected time period. Trade routes can be gleaned if we are seeing pigments and colorants in regions they are not usually found.

What is meant by the term “cultural heritage preservation database” and how can it be used to evaluate deterioration?

This is an initiative I have been working on for a while, to make our data and research more accessible and sharable with colleagues.

The Preservation Research and Testing Division (PRTD) has developed a preservation science infrastructure for collecting preservation data, standardizing the metadata for the description of materials, instruments and test methods, using open source software. The infrastructure initiative – the Center for Library Analytical Scientific Samples Digital (CLASS-D) is a transformative methodology that links multiple analyses to one sample or object, and potentially multiple samples in a project to previous longitudinal research studies.

A key component of this effort is ensuring the vocabulary utilized is linked to existing terminology, to assure a true linked open data (LOD) approach. The PRTD is currently investigating LOD options derived from the CIDOC CRM for modelling conservation, preservation, and heritage data.

As part of the CLASS-D initiative, the Data Visualization Project (DVP) provides an interactive interface for diverse audiences to engage with conservation, preservation and heritage data. Utilizing the International Image Interoperability Framework (IIIF) and the Mirador viewer, a rendering of the object is annotated with conservation, curatorial and preservation science data. The critical aspect with these linked annotations is the capacity to hover over terms and descriptions that are linked open data terms such as from the Getty or IUPAC Gold books for scientific terms.

How can analytical techniques help preserve our cultural heritage for future generations?

Improved understanding of how materials age, deteriorate, are modified in different situations. The more we can characterize down to the molecular level how materials are characterized, and how they are impacted by environmental parameters, the more we can help preserve these valuable materials for future generations to utilze.

Each time we work with an object or material, we can potentially add new information for extending its longevity, and this really is fundamental science. We are always on the lookout for new techniques or applications, especially in the area of non-invasive analytical techniques.

Please describe your research involving the use of multi-spectral imaging to monitor the conservation of cultural heritage objects.

We use multi-spectral imaging to track change over time or assess the impact of putting objects on exhibit, all methods of non-invasively seeing how we can best preserve our heritage and not add any new components (from treatments) that might be a challenge in the future.

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Since discovering the value of multi-spectral imaging in cultural heritage, how have you used this and other analytical techniques in your work?

We now use spectral imaging as the first technique to “map” the spectral response of materials across the surfaces of heritage materials. From that mapping, we can then use that information to see what materials are similar or different. For example, we may ask, "are the blues the same?". We then learn from this information to determine if we need to add additional analytical techniques to characterize the object. These further analysis techniques include - fiber optic reflectance spectroscopy (FORS) Fourier transform infrared spectroscopy (FTIR) x-ray fluorescence (XRF), Raman spectroscopy etc.

By using these creation techniques, we can characterize pigments, inks and colorants, track change, and uncover hidden and obscured information.

What do you think the future holds for the field of cultural heritage science?

Although cultural scientists have been around for many years, it is still a relatively unknown field. Therefore, raising profile of our work and sharing the innate cross-disciplinary nature of what we do at such a reknown, analytical chemistry event like Pittcon, is always important. This is especially the case when dealing with the challenges of climate change, for example, investigating the impact of high humidity on specific materials/regions that have not historically experienced this.

About Pittcon

Pittcon^® is a registered trademark of The Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, a Pennsylvania non-profit organization. Co-sponsored by the Spectroscopy Society of Pittsburgh and the Society for Analytical Chemists of Pittsburgh, Pittcon is the premier annual conference and exposition on laboratory science.

Proceeds from Pittcon fund science education and outreach at all levels, kindergarten through adult. Pittcon donates more than a million dollars a year to provide financial and administrative support for various science outreach activities including science equipment grants, research grants, scholarships and internships for students, awards to teachers and professors, and grants to public science centers, libraries and museums.

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About Dr Fenella G. France

Dr. France is Chief of the Preservation Research and Testing Division at the Library of Congress researching non-destructive imaging techniques, and prevention of environmental degradation to collections. Her current focus is the development of spectral imaging and image processing techniques, and increasing links and access between scientific and scholarly data, developing and providing training workshops to preservation professionals. She received her Ph.D. from Otago University, New Zealand.

After lecturing at Otago, she was the research scientist for the Star-Spangled Banner project at the Smithsonian Institution. An international specialist on polymer aging and environmental deterioration to cultural objects, she focuses on links between mechanical properties and chemical changes from environmental damage and treatment protocols.

Dr. France has worked on projects including the World Trade Centre Artifacts, Pre-Columbian mummies and textiles, the Ellis Island Immigration Museum, and lighting standards for the preservation of cultural heritage. With nearly three decades of experience, she serves on a range of standards and professional committees for cultural heritage preservation and maintains close links and collaborations with colleagues from academic, cultural, forensic and federal institutions. In February 2016 Dr. France was appointed the Council on Library and Information Resources (CLIR) Distinguished Presidential Fellow.