Illuminating yellow and red feathers in museum exhibits: Microfading tests and light sensitivity of their bio-pigments

Résumé En

Microfading tests were introduced into the field of conservation to help collection managers and conservators adapt their lighting policies to light-sensitive artifacts. This technique consists in intensively illuminating a small surface (diameter of 1 mm 2) while simultaneously monitoring the color change (Delta E) in a colorimetric space. After having developed a level of expertise in diagnosing and predicting photodegradation on graphic and photographic collections to support exhibit decisions, the musée du quai Branly–Jacques Chirac (mqB–JC) considered moving on to feathers, of which there are a large number in its ethnographic collection. This study focused on the brightest fathers—yellow and red feathers from the Ara species, colored by psittacofulvin pigments. Two main results are reported. First, the study determined how to perform microfading tests on curved, translucent, textured, and fragile objects made of feathers. Second, it showed that yellow feathers are less sensitive to light than red ones.