student demonstrates UV examination

Ultraviolet (UV) fluorescence provides information about surface layers: the paint, varnish, and restorations. UV light excites electrons in the paint and varnish layers, and as the electrons fall back to their ground, or unexcited state, they emit fluorescent light visible to the eye. Different materials emit different fluorescence, and UV light can help to characterize the age of varnish or show the presence of nonoriginal materials.