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Alison Murray

Scientists have a long history of working with cultural objects.[i] For example, in the late eighteenth century, Claude-Louis Berthollet and André Thouin accompanied the Napoleonic army to the Italian peninsula, where, in addition to other duties, they evaluated the condition of artworks that had been confiscated.[ii] Archaeological pigments from Pompeii were identified in the early nineteenth century by Jean-Antoine Chaptal and by Sir Humphrey Davy.[iii] They made the first qualitative analyses of Egyptian blue, an artificial calcium copper silicate pigment.[iv] In 1850 Michael Faraday gave evidence at a select committee appointed by the British House of Commons on the effect of pollutants from the combustion of coal on paintings in London’s National Gallery. In 1859 Faraday was also part of a commission that studied the effects of the environment, including gaslight, on paintings. While working with these committees, he also promoted preventive measures, such as glazing and using backing materials for paintings, to slow down deterioration.[v] Wilhelm Röntgen first used X-rays in 1895, and soon afterwards they were applied to radiograph a painting.[vi] Scientists have examined other cultural objects in addition to paintings. In the twentieth century, the metallurgist Sir Cyril Stanley Smith investigated how ancient metal objects were made.[vii] He wrote, “the internal structure of a work of art in metal can often throw as much, or more, light on its origin as can be derived from stylistic analysis.”[viii] The earliest museum lab headed by a scientist was at the Staatliche Museen zu Berlin (National Museums in Berlin) in 1888. Other museums where scientists worked followed in the 1910s, 1920s, and 1930s including those at the British Museum in London, Harvard’s Fogg Museum in Cambridge, Massachusetts, the Louvre in Paris, and the National Gallery as well as the Courtauld Institute, both in London. Questions of identification, degradation, and condition of paintings, as well as preventive and cleaning treatments, are still being investigated today. This essay discusses the types of work that continue to engage scientists and how these scientists enter the conservation science field.

Conservation scientists perform analyses and undertake larger research projects, working with conservators, art historians, and curators. A conservation scientist is “a person trained in science who applies his/her knowledge to the conservation of cultural properties.”[ix] These professionals are also known as “heritage scientists” as their work involves more than conservation. A single artwork, a specific material, a collection, or even an artist’s entire oeuvre may be studied in order to learn about art materials, working process, or method of production. Identification of unexpected materials or techniques may indicate that a work is not, or not entirely, authentic. Conservation scientists also routinely work towards preventing problems that arise from the display or storage of artworks. The best environment, including safe light levels, relative humidity, and temperature, needs to be established for the many various materials found in a collection. For example, it is important to guard against changes in relative humidity that cause wood and paint layers in a panel painting to change in dimension and separate. A crucial relationship exists between the scientists and the conservators, who, from treating objects, can identify relevant issues; together they work to develop new conservation treatment techniques. Engineers and scientists also lend their expertise to help determine whether paintings and objects are stable enough to travel for exhibition and, if so, how they should be packed; inappropriate storage containers and packing material can emit noxious gases and cause degradation. In all these cases, professionals with scientific and engineering expertise undertake the basic research needed to answer questions on identification and degradation of cultural heritage materials.

The conservation scientist chooses the appropriate instrumental techniques, analyzes samples, and interprets the results in the context of cultural heritage. For example, ideally the amount of material selected for analysis is very small, with the specific amounts required varying for individual techniques. These selections require the careful planning of sample locations in order to ensure the results are meaningful for the issues being investigated and representative of the entire artwork. Can all the colours be sampled? Is the amount of material to be removed, even when it is microscopic, too large to be acceptable ethically or aesthetically? Does comparative material exist to give context to the results? Have the pigments faded, or has there been other decay to the material? Analysis exploring these questions can give surprising results. Scientists help to develop conservation treatments that must stand the test of time.[x] Scientists investigate newly developed products to see if they will improve the stability of cultural heritage objects undergoing conservation treatment. Extensive preliminary testing should prevent the use of harmful products that can cause deterioration, requiring conservators to undo previous treatments. Materials testing through accelerated aging and the use of samples that mimic actual cultural heritage objects can only give so much information. For work on actual artifacts, the principles of minimum intervention and continuing care and maintenance guide sound conservation practice today.

Newer techniques and instrument improvements continue to be developed, and there is a strong interest in applying these advances to the conservation and technical analysis of cultural heritage. An X-ray fluorescence spectrometer (XRF) for elemental analysis was used extensively when analyzing paintings for The Unvarnished Truth: Exploring the Material History of Paintings. Developments in the twenty-first century have made portable and lightweight units available. The Getty Conservation Institute (GCI) is one of several organizations that have developed noninvasive, portable X-ray diffractometers with XRF spectrometers (XRD/XRF).[xi] Had this combination of techniques been available to the researchers involved in this exhibition, it would have contributed greatly to The Unvarnished Truth as it would have given exact, nondestructive identification of crystalline pigments rather than only elemental analysis with XRF. Another recent development is the macro-scanning XRF spectrometry developed through a university-industry collaboration by the University of Antwerp in Belgium, the Delft University of Technology in the Netherlands, and Bruker Nano in Germany. This portable device allows paintings to be scanned with a high spatial resolution, identifying elements that make up the top surface and subsurface of the paint structure.[xii]

The clearly defined goals of any research project guide the scientist in choosing appropriate techniques. The information thereby gained is evaluated critically to determine its relevance. For some analyses, the art object may need to travel to a specific instrument, in which case the stability of the object must first be determined to ensure its long-term safety. New techniques are often expensive, and while analytical laboratories may be willing to perform some initial analysis free of charge, usually this cannot continue in the long term. Since achieving greater accuracy will often be more expensive, the scientist must ask if the likely results are worth the greater expenditure.

At this time of limited budgets and fiscal restraint, conservation professionals are looking at ways to work more effectively and create greater impact. At the 2013 ICCROM[xiii] Forum on Conservation Science, “Conservation Science in Context,” professionals stressed that educating the public about the value of their work can generate numerous economic and social benefits.[xiv] The Unvarnished Truth is a wonderful example of bringing the analysis of cultural heritage to the attention of the public, and increasing awareness of scientific vocabulary, concepts, and techniques. The University of Delaware, funded by the Samuel H. Kress Foundation, recently launched a website aimed in part at providing project material for students in kindergarten to grade 12; it describes painting reconstructions and documentation techniques.[xv] The Art Gallery of Ontario’s recent exhibition Revealing the Early Renaissance: Stories and Secrets in Florentine Art included a display of pigments as well as the art objects themselves.[xvi] These three examples help the public to feel closer to artists by increasing understanding of their materials and highlighting the tangible aspect of creating works of art.

The applied field of art conservation often relies on interdisciplinary research groups that, in working together, face challenges arising from the priorities and vocabularies that vary according to discipline, and from difficulties in transferring research results into usable information. The 2014 report “Mind the Gap: Rigour and Relevance in Heritage Science Research” discusses these points as well strategies for effective collaboration, including pre-project time and funding to promote strong relationships before the actual start of a project.[xvii] The 2013 ICCROM Forum on Conservation Science also generated specific suggestions for increasing the impact of conservation science on heritage conservation. These included improving access to research facilities, making funds available for applied research projects, and running training courses that apply research outcomes. This last idea has been implemented for several years at the Cleaning of Acrylic Painted Surfaces Workshops organized by the GCI. Science researchers from the GCI and the Tate Modern discuss their current research with practising conservators, who then apply various cleaning methods to test samples and give their feedback directly to the science research team.[xviii] A simple method of inviting suggestions is used at the annual conference for the Canadian Association for Conservation, where conservators are routinely surveyed about where they feel scientific research is needed. Collaborative research is unquestionably valuable, but improved methods for implementation are needed.

Many of the world’s larger museums have scientists on staff; however, in Canada, we have a separate institution, the Canadian Conservation Institute in Ottawa, where a large group of scientists and engineers work with conservators. Conservation scientists in Canada also work at Parks Canada and various universities, such as the Art Conservation Program at Queen’s University. Training for conservation scientists has not been as formalized as it has been for conservators. Chemists (for example in analytical, organic, inorganic, or polymer science), biologists, material scientists, and mechanical and civil engineers may come into the cultural heritage field after completing their degrees or sometimes through fellowships. Some of these professionals enhance their expertise by taking a conservation treatment master’s degree, where they may work on paintings, works of art on paper, or objects. In North America and Europe, there are special programs for conservation science. For example, Queen’s offers a Master of Art Conservation degree, where science or engineering students carry out heritage science thesis research. More funded PhD opportunities would be welcomed, for example, through joint projects between professors in chemistry or materials science departments, and conservation programs, museums, or other cultural heritage institutions.

The world of cultural heritage offers numerous opportunities for scientific exploration. Conservation departments in art galleries and museums throughout Canada would welcome visits from interested scientists, possibly leading to future collaboration.

A heartfelt thanks to everyone who read and commented on my essay including colleagues on this project as well as Dorothea Burns, Michael O’Malley, and the project editor, Joan Padgett.

[i] Jilleen Nadolny, “A History of Early Scientific Examination and Analysis of Painting Materials ca. 1780 to the mid-Twentieth Century,” in Conservation of Easel Paintings, ed. Joyce Hill Stoner and Rebecca Rushfield (New York: Routledge, 2012), 336–40; Nadolny, “The First Century of Published Scientific Analysis of the Materials of Historical Painting and Polychromy, circa 1780–1880,” Reviews in Conservation 4 (2003): 39–51.

[ii] Cathleen Hoeniger, “Art, Science and Painting Restoration in Napoleonic Italy, 1796–98,” in Conservation in the Nineteenth Century, ed. Isabelle Brajer (London: Archetype Publications Ltd., 2013), 15–28.

[iii] Nadolny, “The First Century of Published Scientific Analysis,” 45.

[iv] Josef Riederer, “Egyptian Blue,” in Artists’ Pigments: A Handbook of Their History and Characteristics, vol. 3, ed. Elisabeth West Fitzhugh (New York, NY: Oxford University Press, 1997), 28.

[v] David Saunders, “Pollution and the National Gallery,” National Gallery Technical Bulletin 21 (2000): 77–94.; Nicola Costaras, “Richard Redgrave (1804–1888): First Curator of Paintings at the South Kensington Museum,” in Conservation in the Nineteenth Century, ed. Isabelle Brajer (London: Archetype Publications Ltd., 2013) 58–9.

[vi] Nadolny, “A History of Early Scientific Examination and Analysis,” 339.

[vii] Cyril Stanley Smith, “The Interpretation of Microstructures of Metallic Artifacts,” in A Search for Structure, Selected Essays on Science, Art, and History (Cambridge, MA: MIT Press, 1982) 69–111.

[viii] Smith, 109.

[ix] Marie-Claude Corbeil, “Training Options for Conservation Scientists,” in University Postgraduate Curricula for Conservation Scientists: Proceedings of the International Seminar Bologna, Italy, 26–27 November 1999 (Rome: ICCROM, 2000): 104.

[x] Giorgio Torraca, “The Scientist’s Role in Historic Preservation with Particular Reference to Stone Conservation,” in Historical and Philosophical Issues in the Conservation of Cultural Heritage, ed. Nicholas Stanley Price, M. Kirby Talley Jr., and Alessandra Melucco Vaccaro‬ (Los Angeles: Getty Publications, 1996) 439–44.‬‬‬‬

[xi] “New Portable X-Ray Diffraction/X-Ray Fluorescence Instrument (XRD/XRF),” The Getty Conservation Institute, last modified April 2009, https://www.getty.edu/conservation/about/science/portable_xrd_xrf.pdf; Alexandra Gianoncelli, Jacques Castaing, Luc Ortega, Eric Dooryhee, Joseph Salomon, Philippe Walter, Jean-Louis Hodeau, and Pierre Bordet, “A Portable Instrument for In Situ Determination of the Chemical and Phase Compositions of Cultural Heritage Objects” X-Ray Spectrometry 37 (2008): 418–23.

[xii] Matthias Alfeld, Joana Vaz Pedroso, Margriet Eikema van Hommes, Geert Van der Snickt, Gwen Tauber, Jorik Blaas, Michael Haschke, Klaus Erier, Joris Dik, and Koen Janssens, “A Mobile Instrument for In Situ Scanning Macro-XRF Investigation of Historical Paintings,” Journal of Analytical Atomic Spectrometry 28 (2013): 760–67.

[xiii] International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM), based in Rome, Italy.

[xiv] 2013 ICCROM Forum on Conservation Science, “Conservation Science in Context,” /, last modified November 16, 2013, http://forum2013.iccrom.org/ and http://forum2013.iccrom.org/programme.

[xv] “Technical Art History Website,” University of Delaware, last modified February 25, 2015, www.artcons.udel.edu/about/kress.

[xvi] Revealing the Early Renaissance: Stories and Secrets in Florentine Art, last accessed November 16, 2014, http://www.ago.net/revealing-the-early-renaissance-stories-and-secrets-in-florentine-art.

[xvii] Nancy Bell, Matija Strlič, Kalliopi Fouseki, Pip Laurenson, Andrew Thompson, and Catherine Dillon, Mind the Gap: Rigour and Relevance in Heritage Science Research Report, The National Archives, Kew, Richmond, United Kingdom, last accessed November 16, 2014, http://www.nationalarchives.gov.uk/documents/mind-the-gap-report-jan-2014.pdf.

[xviii] “Cleaning of Acrylic Painted Surfaces,” The Getty Conservation Institute, last modified October 2013, http://www.getty.edu/conservation/our_projects/education/caps/caps_overview.html.