The Micro Fading Tester (MFT) measures temporal behavior of dyes under irradiation.
MFT tests allow to rank objects in collections by their sensitivity to light.
This approach allows to adopt exhibition policies to
actual data obtained for each tested object rather than use
general assumptions which could be either too conservative
and unnecessarily limit viewers access to the object or too optimistic
and lead to irreversible light-induced damages.
The MFT allows to measure color change under illumination in a non-destructive way:
(1) the spot of light on a sample has only 0.5 mm in diameter, (2) the total color change (∆E)
for the selected point is constantly monitored during the measurement and the operator
and/or the instrument software could stop the test when ∆E reaches a selected threshold value
(i.e. below reaching the level of just noticeable difference).
In practice, for non-glossy objects fading marks are never visible unless fading was performed
to reach extreme ∆E values (>15).
The micro fading tests could be performed for nearly all classes of materials found in
museum collections, and is particularly suited to study fugitive objects (works on paper –
manuscripts, prints, watercolors; canvas paintings; textiles). Some classes of objects cannot
be tested by the MFT method or their testing is difficult to perform or to interpret obtained
results – objects of a very high light stability and objects interacting with light in an non-typi-
cal manner (highly reflective or transparent). The MFT instrument could be regarded as
portable and so it could be moved within the museum to the objects’ location,
which is particularly important in case of large artefacts (e.g. wall paintings, sculptures, maps)
or objects of significant value.