Microfadeometry is a technique that uses tiny spots of intense light to probe and measure color changes in objects of art that are particularly sensitive to light exposure.Microfade Testing Service
Canadian Conservation Institute. (2014, June 2). This process is completed using a recently designed instrument known as a microfading tester. The data from the test is represented by a reflectance spectra.

History

Light-fastness testing dates back to as early as 1733. In the late 19th century with early art conservation studies, Russell and Abney published Action of Light on Watercolors in 1888 sparking a concern with light and the aging of cultural materials.Druzik, J. Oriel Microfading Tester (MFT): a Brief Description. ''Research and Technical Studies''. 2010, ''2'', 1-14. Microfading, as a technique, was first identified in Paul Whitmore’s lab book entry on September 21, 1994. His work on the topic was later published in 1999.Ford, B. Non-Destructive Microfade Testing at the National Museum of Australia. ''The Australian Institute for the Conservation of Cultural Material Bulletin''. 2011, ''32'', 54-64.

Application

Before the creation of this technique, recording light-stability information directly from the objects was nearly impossible. Through the use of microfading technology, it is now possible to obtain both information about the chemical characterization of the dyes and the associated kinetics of color change. Benchtop microfaders and microfading testers are used to test and analyze light damage on cultural objects and potential light damage to objects in museum collections.Chiari, G. Conservation Science Investigation. ''International Preservation News''. 2010, ''50'', 11-16.

Theory

Using a powerful xenon arc lamp, 1 lumen of light is focused through an optical fiber onto a 300–400 μm spot of the object’s surface. The reflected light is collected by a second fiber optic. The period of exposure is monitored with a probe that transforms the reflectance spectrum into color coordinates in real-time. A typical microfading test is achieved in less than 10 minutes and replicates exposures equivalent to 5–12 years of display at normal museum light levels.del Hoyo-Melendez, J. Micro-fading Spectrometry. ''Fibers and Polymers''. 2012, ''13'', 1079-1085. The output of the xenon arc lamp is kept at a constant by an exposure controller while it is filtered to 400–710 nm using a water filter.Arnaud, C.H
Shining Light On Art
Shining Light on Art. ''Chemical & Engineering News''. 2009, ''87'', 44-55. The spectrum is then used to quantify the amount of time it would take for the color change to result in a noticeable difference. This information is used to retrofit display conditions and improve the protection of vulnerable objects. Calibration of the instrument is achieved by using internal standards such as the Blue Wool Scale.Lerwill, A
Microfading: Questioning the Basics
Microfading: Questioning the Basics. ''Image Permanence Institute Bulletin''. 2013.

Reliability

Concerns associated with microfading techniques include: diffusion-limited photo-oxidation reaction rates, dehydration and heating of the sample, the variability of using and measuring ISO Blue Wool Standards, variation in spectral power distribution between lamps used in object display and the lamp used in accelerated light aging, the small sampling area, the required number of sample the length of fading time and the potential interaction of individual chemical components of the object tested.

Institutional Use

Cultural institutions that house their own instruments for microfadeometry include: the Library of Congress and the

National Gallery of Art The National Gallery of Art, and its attached Sculpture Garden, is a national art museum in Washington, D.C., United States, located on the National Mall, between 3rd and 9th Streets, at Constitution Avenue NW. Open to the public and free of char ...

in Washington DC, the Museum of Modern Art in New York, the Canadian Conservation Institute in Ottawa, the Los Angeles County Museum of Art, the Art Conservation Department at Buffalo State College in New York,Museum Lighting Research
J. Paul Getty Trust. (2010, July). The National Archives (United Kingdom), the Scottish National Gallery (United Kingdom), Qatar National Library (Qatar), French National Centre for Scientific Research in Paris,

Philadelphia Museum of Art The Philadelphia Museum of Art (PMoA) is an art museum originally chartered in 1876 for the Centennial Exposition in Philadelphia. The main museum building was completed in 1928 on Fairmount, a hill located at the northwest end of the Benjamin Fr ...

in the USA, Gothenburg University in Sweden, National Museum of Art, Architecture and Design in Norway, Kunstmuseum Basel in Switzerland, United States Holocaust Memorial Museum, National Library of Norway, National Taiwan Museum of Fine Arts,

State Academy of Fine Arts Stuttgart The State Academy of Fine Arts Stuttgart (German: Staatliche Akademie der Bildenden Künste Stuttgart) is a university in Stuttgart, Germany. Founded on 25 June 1761, and located since 1946 on the Weißenhof, the Academy, whose historical sig ...

in Germany, and other institutions.Instytut Fotonowy
Micro Fading Tester.(2020, February).

References

{{reflist Conservation and restoration of cultural heritage Museology Cultural heritage Applied sciences