Advancing Microfading Tester Practice

Light plays an integral role in facilitating access to a collection item while simultaneously acting as an agent of deterioration. Determining the balance between access to and protection of an object and/or collection has been a significant focus of lighting policy discussions. Lighting decisions have previously relied on light sensitivity assessments using mock-up samples and color comparisons of objects before and after display; this information is integrated in published guidance on the light sensitivity of various classes of artists’ materials. However, these approaches may not produce data that represent an item’s specific material composition and display history. The microfading tester addresses this issue by providing a means of directly assessing the light sensitivity of an object.

Developed by Paul Whitmore and introduced to the field in the mid-1990s, the microfading tester rapidly induces and monitors color change of an object. This is achieved by exposing the sample surface to a high-intensity, stable, and focused light spot and simultaneously examining the affected area using a spectrophotometer. The resulting impact on the object is mitigated by the small area of exposure and the termination of the test before change is visible.

Though the microfading tester (MFT) has been accepted as an important preventive conservation tool, there remain obstacles to its more widespread use. Recent MFTs have expanded on the original design by employing various light sources, measurement geometries, and means of automation, leading to some ambiguity as to which iteration is most appropriate for a specific context.

MFT is also a rare example of an analytical technique emerging from within the conservation field rather than having been transferred from a larger external field. As a consequence, instrumental support and training that might be provided by a commercial company is limited, and a self-supporting MFT user community remains underdeveloped. Access to didactic information about MFT is particularly important for sustaining institutional knowledge about an instrument that may be operated and maintained intermittently.

• Develop collaborative in-person and virtual training opportunities for the microfading tester (MFT)
• Address specific MFT research questions, such as the impact of varied spectral power distributions, that seek to define the technique’s boundaries
• Cultivate an instrument loan program to increase access to the instrument for small and medium-sized heritage institutions and private collections
• Improve MFT data analysis and compatibility with various spectrometer outputs through revisions of Getty Conservation Institute’s Spectral Viewer software, in collaboration with The Field Museum, Chicago
• Update the directory of MFT users and owning institutions to promote regional and global dialogue about the technique