Advancing heritage science with spectroscopic imaging

The conservation, preservation and interpretation of our cultural heritage requires a multi-disciplinary approach, bringing together experts in the fields of science and the arts and humanities. Analysis of the materials of our cultural heritage collections has a vital role in understanding how and why they were made and used, their conservation history, the origin and mechanisms of material decay, and how deterioration has affected appearance and perception. It is part of a responsible modern approach to conservation.

Microsamples from paintings and objects are often prepared as cross-sections to examine their highly revealing microstructure and stratigraphy. The distribution of materials within the layer structure, or even within an individual layer, reflects the working practices of the artist/maker, the changes that have been initiated by environmental conditions, pollutants or the passage of time, as well as the use and conservation history, including interventions by restorers. The distribution helps to differentiate between original materials and later restorations or additions, as well as deterioration products, which is crucial when undertaking conservation treatments and interpreting the original appearance of the object. It is also important in understanding the causes of decay, informing decisions on storage and display of objects. Although analysis of inorganic components in a cross-section is reasonably straightforward, this is not the case for organic materials, which are very difficult to characterise with the techniques currently available to heritage scientists.

The project will develop the application of micro-ATR-FTIR spectroscopic imaging combined with data processing using multivariate methods to the analysis of cross-sections from cultural heritage paintings and objects. Other conventional IR spectroscopic techniques are of proven value in the field but this emerging technique is the only one that has the potential to become a routine and rapid method to simultaneously characterise both organic and inorganic materials directly (at a molecular level) on cross-sections, at the same time as determining their distribution with the necessary high spatial resolution. This would greatly improve analysis of organic surface coatings or components, understanding of which is crucial for solubility behaviour during cleaning of objects. It will ensure that advice from heritage scientists on the care and conservation of collections is based on the best possible data, improving conservation practice and our ability to preserve our national collections for future generations.

The spectroscopy expertise at Imperial College London (host organisation) will be combined with expertise in the heritage field at the National Gallery and the British Museum (project partners). The postdoctoral researcher, hosted at Imperial College London, will develop the methodology of ATR-FTIR imaging on test samples, before applying it to a wide range of samples from real objects (involving time working at the partner institutions). This will demonstrate the versatility of the technique and at the same time generate new information which can answer unsolved questions about the objects and paintings studied that cannot be obtained using current techniques. The new skills that the postdoctoral researcher will develop during the research, and the experience gained from working in a leading spectroscopic imaging group as well as two prominent cultural heritage institutions, will increase capacity in heritage science. Interaction with curators and conservators will ensure that their needs influence the development of the research and that the new insights gained into the objects studied can directly improve the way in which the National Gallery, the British Museum and other institutions charged with the care of cultural heritage interpret, study and present their collections to the public.

The improvements in the scientific study of cultural heritage that ATR-FTIR imaging offers, and the knowledge generated during the research, will be of interest and value to specialists in many different disciplines in the heritage field, including curators, conservators and scientists who are responsible for the care of collections, as well as archaeologists and art historians who carry out academic research.

There will be an immediate impact on the partner organisations, in that the research can contribute to technical examination during ongoing conservation work over the course of the project. In the longer term, the technique has the potential to be of benefit to conservators by improving understanding of the microstructure of cultural objects and paintings, as well as the mechanisms of decay. The information on materials and technique of production of paintings/objects produced during the project can be of benefit to the scholarly research of the curators and also to interpretation of the collection and engagement with the public through the many different routes employed at the NG and BM (catalogues, website, labels, gallery talks etc). It is a field that captures the imagination of the public and has proved in the past to be an effective means of increasing public understanding of science and of attracting new audiences.

Every day many visitors from the UK and overseas visit the British Museum and the National Gallery to enjoy and learn from their collections. They are central in the cultural life of the UK and make a significant contribution to the tourist industry. Advancements in heritage science such as that proposed in this project are needed to ensure that developments in other fields such as spectroscopic imaging can be exploited in museums and galleries to ensure that the best possible scientific research is used to inform the care, conservation, display and interpretation of the collections, so that they are preserved for future generations.

The multidisciplinary nature of this project, working directly with practitioners and researchers in the heritage field, increases the likelihood of impact. Development of the project will be influenced by the ideas and opinions of the end users, ensuring that they benefit from this research and in the long term this collaboration will foster better communication and mutual understanding between the different disciplines which will benefit future research. All three institutions involved in the project have existing international networks which can be exploited for effective dissemination of the work. Detailed plans for communication and engagement with both specialists and the public are outlined in the Impact Plan.