Anoxia and Microfading: The Impact on Collection Care – Part 15: Mark Underhill
Dr Mark Underhill, Analyst, Tate, London: ‘Oxygen Measurement’
The Ocean Optics NeoFox system for remote measurement of oxygen concentration is explained and its application to measuring the change over time of the oxygen concentration inside the sealed frames is described. The system uses self-adhesive patches containing a fluorescent ruthenium complex. The fluorescence is quenched in the presence of oxygen with the degree of quenching related to the partial pressure of the oxygen. A probe delivers blue excitation light and collects emitted red fluorescence. The patches are placed on the inside of the glass and the probe is placed in contact with the glass directly over the patch. The system was used to measure the change in the oxygen concentration over time in two sets of sealed frames, one using silicone seals and one using butyl. Extrapolation of the measurements showed that the butyl seals would hold an atmosphere of less than 1% oxygen for at least 100 days.
Mark Underhill was a forensic scientist for more than thirty years with the Metropolitan Police Forensic Science Laboratory (latterly the Forensic Science Service). Since 2008 he has been working at Tate as an analyst in the Conservation Science and Research departments. For the Tate AXA Art Modern Paints Project (TAAMPP), he developed a method for Direct Exposure Mass Spectroscopy (DEMS) as a rapid technique for identifying pigments, paint media and extenders in acrylic and other types of paint in samples taken from works in Tate’s collection. Subsequently he investigated the GC-MS analysis of head-space vapours for the volatile organic acids produced by the wooden frames, showcases and crates that are used to contain and transport works of art. As the analyst in the Anoxic Framing project his main role has been to investigate and deploy methods for measuring the oxygen concentration inside the anoxic frames.
Anoxia and Microfading: The Impact on Collection Care – Part 16: Bertrand Lavédrine
Dr Bertrand Lavédrine, Director, Centre de Recherche sur la Conservation des Collections (CRCC-CNRS), Paris: ‘Development of Microfading Testing for Transmission Measurement on Colour Transparencies’
The microfading tester is a very promising tool that allows assessing the light fastness of coloured artefacts in an, almost, non destructive mode. Existing MFT setups measure the change of the light spectrum reflected from the object surface. Museums might sometimes benefit from a MFT in transmission mode for characterising the light sensitivity of coloured objects such as photographic colour transparencies (Finlay, Paget, Omnicolor, Autochrome, chromogenic slides, digital prints on transparencies, etc.). These processes are nowadays very popular and museums are willing to exhibit them on light boxes but are faced with a lack of data on their behaviour during display. To address this question, the CRCC implemented the MFT on a transmission microscope and was able to follow the colour change on single coloured starch grains of autochrome plates smaller than 15 micrometers. The optical fibre illuminates the plate attached to the microscope holder from beneath, and the colour measurement is made through the video output of the microscope using the other optical fibre.
Bertrand Lavédrine holds a Masters degree in organic chemistry and has a PhD in Art and Archaeology. He is Professor at National Museum of Natural History, in France, and since 1998 the director of the Centre de Recherche sur la Conservation des Collections: a national scientific research institute carrying out research for the preservation of museum collections. He was head of the conservation training program at the Sorbonne for four years and wrote papers and books on the preservation of photographs in French, English and Spanish. He received different awards: The European Prize for Innovation, Kraszna-Krauz Photography Book Awards and Chevalier des Arts et des Lettres. He is a member of the Board of Non Profit Organisations and was treasurer of the Conservation Committee of the international council of museums (ICOM-CC). He is currently coordinator of the European Commission funded project POPART: A research project for the preservation of plastic artefacts in museum collections, gathering thirteen partners from eight countries.
Anoxia and Microfading: The Impact on Collection Care – Part 17: Haida Liang
Dr Haida Liang, Reader in Physics, Nottingham Trent University: ‘Latest Developments on Portable Microfading Spectrometry at Nottingham Trent University’
Ten years since the invention of the first microfadometer, new microfading spectrometers with improved portability (a few kilograms) and accuracy are built taking advantage of the availability of compact light sources and portable fibre optic spectrometers. The latest instrumental development of microfading spectrometry at the Imaging Science for Archaeology and Art Conservation group of Nottingham Trent University includes a compact probe head that is robust and easy to transport without the need for re-alignment, a fully automated computer control system that streamlines the focusing, light source shutter, the spectrometer operations and X-Y positioning. The automatic control of the various hardware components not only increases the ease of data collection but also ensures the synchronization of fading (light source shutter control) with spectral measurements for improved accuracy. Auto focusing also improves the measurement precision. The improved portability and ease of use can potentially increase the use of microfading tests to assist conservation management decisions. The effect of various parameters such as surface texture, thickness of paint and substrate on the results from microfading will be examined. The validity of accelerated aging methods depends on the reciprocity principle to a large extent. The microfading spectrometers operate at a light intensity level that is at least four orders of magnitude greater than exhibition lighting. The validity of reciprocity in the context of microfading will be discussed. Finally, a new method of evaluating fading rates using the measured spectra rather than colour will be presented.
Haida Liang is Reader in Physics at Nottingham Trent University. She gained a PhD in Astronomy and Astrophysics from the Australian National University. Prior to her current post, she worked at the Scientific Department of the National Gallery, London on the development of non-invasive techniques for the examination of paintings, the Physics Department of the University of Bristol, Service d’Astrophysique of Commissariat à l’Energie Atomique (Saclay) and Australia Telescope National Facilities on various Astrophysics projects. Her main research interests are the development and application of non-invasive imaging and spectroscopic techniques to art conservation and archaeology. She is currently leading the Imaging Science for Archaeology and Art Conservation group within the School of Science and Technology at Nottingham Trent University.
Anoxia and Microfading: The Impact on Collection Care – Part 18: Julio M. del Hoyo-Meléndez
Dr Julio M. del Hoyo-Meléndez, Scientist, National Museum of Kraków: ‘Microfade Testing: A Promising Tool for Evaluating the Light Fastness of Coloured Fabrics and the Impacts on Lighting Policy’
Julio M. del Hoyo-Meléndez, and Marion F. Mecklenburg, Smithsonian Institution, Washington
The Smithsonian Institution decided to revise their museum lighting guidelines shortly after the reopening of the National Portrait Gallery and the American Art Museum. A light levels survey of the exhibition spaces of these two museums was performed since sensitive works in the collection were believed to be at risk of induced photochemical damage. This research was supported by microfade testing, which was used concurrently to evaluate the light-stability of a series of model textile samples and several organic-based museum objects. The technique proved effective for supporting exhibition design procedures and also when used as a research tool to study a series of museum illumination issues. Microfading spectrometry permitted to investigate the reciprocity principle of light exposures by evaluating the color changes experienced by a series of model textile samples. Also, a procedure based on microfade testing was developed to conduct rapid light-stability screenings of materials exposed to an argon atmosphere.
Julio M. del Hoyo-Meléndez currently works as a scientist in the Laboratory of Analysis and Nondestructive Investigation of Heritage Objects at the National Museum in Kraków, Poland. He holds a PhD in Science and Conservation of Cultural Heritage from the Department of Conservation and Restoration of Cultural Heritage of the Polytechnic University of Valencia, Spain. In 2007, he was awarded a predoctoral fellowship at the Smithsonian Museum Conservation Institute for conducting research on the action of light on cultural heritage materials. He was a science graduate intern in the Museum Research Laboratory of the Getty Conservation Institute in Los Angeles from 2005 to 2006. He worked as an assistant conservator of paintings, objects, and works of art on paper in both museum-based and private studios, from 1998 to 2004. In 1997, he obtained his MS degree in chemistry from the University of Houston and three years before completed his BS in chemistry at the University of Puerto Rico.
Anoxia and Microfading: The Impact on Collection Care – Part 19: Eric Hagan
Dr Eric Hagan, Conservation Scientist, The Canadian Conservation Institute, Ottawa: ‘An Overview of Current Light-Fastness Testing at the Canadian Conservation Institute’
The Canadian Conservation Institute (CCI) has acquired a number of tools for studying the light sensitivity of artist materials. In 2008, a micro-fading apparatus was assembled using the design offered by Whitmore at the Carnegie Mellon University. This device has become an important tool for rapidly assessing the light-fastness of dyes and pigments found on objects in Canadian collections, and for providing recommendations on future care. A series of light-boxes were also recently constructed for ‘macro-fading’ of test samples under different light sources at illuminance levels in the klx range. The general design of the light-boxes followed that of Saunders at the British Museum, and Druzik at the Getty Conservation Institute. The two techniques provide a means for determining the light sensitivity of colourants under different intensities, spectral power distributions (SPD), and at different scales. Colourant fading measurements will also provide a foundation for the web-based light damage calculator developed by Michalski at CCI. An overview of these tools and techniques will be discussed along with some recent case studies that include micro-fade testing of fountain pen ink on the Canadian Constitution, and anoxic storage of the Royal Charter of the Hudson’s Bay Company.
Eric Hagan is a recently appointed conservation scientist in the Preservation Services Group at the Canadian Conservation Institute. He obtained Master’s degrees at Queen’s University, Canada through the Department of Mechanical Engineering in 2002, and the Art Conservation Program in 2004. Eric went on to study the mechanics of modern artist paints with a doctoral fellowship from Tate, and obtained a PhD from the Department of Mechanical Engineering at Imperial College London in 2009. His research interests relate to the influence of environmental factors on mechanical and colour properties of artist materials.
Anoxia and Microfading: The Impact on Collection Care – Part 20: Discussion 2
Discussion 2: Round table discussion – microfading instrumentation (standardisation, instrument design, reciprocity, the use of blue wool standards, consistency of results)
Panel: Bruce Ford, Consultant Conservator and Scientist, Tate, London; Dr Eric Hagan, Conservation Scientist, The Canadian Conservation Institute, Ottawa; Dr Julio M del Hoyo-Meléndez, Scientist, Laboratory of Analysis and Nondestructive Investigation of Heritage Objects, National Museum of Kraków; Dr Haida Liang, Reader in Physics, Nottingham Trent University; Dr Bertrand Lavédrine, Director, Centre de Recherche sur la Conservation des Collections (CRCC-CNRS), Paris; Dr Han Neevel, Senior Conservation Scientist, Netherlands Cultural Heritage Agency, Amersfoort; Boris Pretzel, Principal Scientist, Victoria and Albert Museum, London
Chair: Dr Joyce Townsend, Senior Conservation Scientist, Tate, London
Anoxia and Microfading: The Impact on Collection Care – Part 21: Plenary
Working session and Plenary
Working session with George Gawlinski, Planning Together Associates to build collaborations and explore the research agenda:
What is the most important thing that this research field should do next? What will enable these technologies to reach their potential for the care of collections? Where will they have the most impact?
This two-day international conference presented current knowledge, recent research and practice-based case studies exploring the use of low-oxygen environments and microfading measurements to establish the boundaries for safe display of light-sensitive objects.The event coincided with the culmination of a five-year Tate research project funded by the Department for Business, Innovation and Skills (BIS) Public Sector Research Exploitation Fund.
The project focused on developing a commercially available low-oxygen enclosure for the protection of works of art on paper. Central to this research has been the use of microfading as a tool to demonstrate how low-oxygen environments can minimise light damage during display, as well as studies of the effects of anoxia lowering the oxygen concentration on colorants. The aim of the conference was to bring together experts in the field to assess the risks and opportunities of these technologies, including the potential for cost reduction, increased public access to light-sensitive works, and their contribution towards the sustainable museum. This conference will be of interest to cultural heritage, museum and collection-care professionals, students, academic researchers, and all who work with fine art, manuscript, archaeological, textile, natural and social history collections.