Microfade testing (MFT)

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Contributors: Kirsten Dunne, J. P. Brown, Vincent Beltran, Cindy Connelly Ryan, Rio Lopez, Catherine H. Stephens (wiki editor)

Overview

Welcome to the Wiki page for Microfade Testing (Microfading), which is being monitored and edited by the AIC Microfading Tester International Discussion group.

This page will cover as much information as possible on Microfading, its history, applications, the different models available, and how to build, run and use them. There is also a resources section at the end with links to many different resources.

Please also see the Library on the International Discussion groups page as this includes a user directory.

• Technique: Microfade Testing (MFT), microfading
• Formal name: Microfade Testing (MFT)
• Microfading was developed as an analytical and a risk management technique and tool. It assesses the relative light sensitivity of the colourants of an object using a Microfader, which is a piece of equipment that allows the rapid non-destructive testing of the relative light sensitivity of an object or artwork.
• Testing is carried out in-situ on objects / artworks themselves, as opposed to samples taken from them.  
  

  Data from MFT experiments. Blue Wools act as controls with Blue Wool 1 being the least light stable and Blue Wool 3 being more light stable. Data is compared to the Blue Wool standards to determine light stability (C. Stephens)

Basic schematic diagram of the principle of a microfader (created by Kirsten Dunne)

Details

• The technique was developed in the late 1990s by Conservation Scientist Dr Paul Whitmore. Dr Whitmore wanted to develop Microfading as an accessible and approachable tool and as a method of locating dyes and pigments likely to fade rapidly under gallery lighting conditions to enable collection care professionals to make informed display choices.
• Results are gathered by exposing the chosen test area to a high-intensity, stable and focused light spot over a designated period of time (a fade test run, usually around 10 minutes). The area is assessed throughout the fade test run by a spectrometer and data is gathered on the relative rate of change and how the color behaves during this time. The data is then compared to a reference material, currently typically Blue wool standards 1-4 (CIE1976, or BWs 1-3 CIE2000). The data gathered can then be presented as relative fading rates, in addition to color fading curves for each test site.
  
• Limitations of this technique (egs: doesn't detect metals, must have certain quantities present, reproducibility, etc) Must be calibrated each time it is used. Isn't good for metals or very light stable objects. Doesn't seem to account for color shifting, only fading.
• Can/how can this technique be made quantitative? It is a semi-quantitative technique. Data from art objects are always compared to the Blue Wool Standards, which have known light stabilities.

Samples

• Phases it can be used to examine (gas, liquid, solid)
• Is this technique non-destructive?
• How invasive is this technique?
• Minimum size of sample necessary to use this technique?
• Time to run one experiment?
• Sample preparation methods [ed note: feel free to add references like ASTM or ISO methods, including numbers and name]

Methods

• Placeholder to describe or link to run the test - temperature conditions, voltages, wavelengths used, column, etc
• Variables to consider when running this method

Applications

• Examples of how this technique is used in the field?
• Risks associated with using this technique?

Budgetary Considerations

• Approximate cost to purchase equipment for this technique?
• Annual cost to maintain or run?
• Sample analysis costs?
• Time it may take to get results from a contract laboratory?

Case Studies [provide description and links]

• Mae West lips sofa – microfading • V&A Blog (vam.ac.uk)

Additional Information

• Complementary Techniques [describe and link]
• Variations of this technique [describe and link]

References, Resources, Databases, Publications

• microfading.com
• In situ Accelerated Light Ageing with Portable Microfade Spectrometry - Nottingham Trent University
• Presentations from conference on anoxia and microfading - Conservation DistList (culturalheritage.org)
• A quick guide to microfading: How, what and why? - The National Archives blog
• Advancing Microfading Tester Practice - Getty Conservation Institute (GCI)
• Microfading Tester: Light Sensitivity Assessment and Role in Lighting Policy - GCI

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