The painting under UV light
The Gallery’s painting Christ Driving the Traders from the Temple from after 1569.
Conservators use UV light when restoring and conserving paintings. The light reveals old damage and restorations that are not always visible to the naked eye.
When you subject a painting to UV light you will see different kinds of fluorescence reflected by the different materials in the painting. Different kinds of varnish fluoresce in different shades. For example, old varnish gives off a more greenish fluorescence than new varnish. The conservators can also learn much by examining pigments that give off different fluorescence. For example, they can see whether any repairs date back from the time when the painting was originally created, or whether the repairs were made later. If such repairs were made long after the painting was originally made they may have used materials that age differently from the original materials. This means that conservators must sometimes remove old repairs to make new ones.
Using UV light when restoring
Before the conservators begin restoring a work they always check the piece under UV light first. This shows them:
- whether the varnish has been applied evenly
- if there is any damage
- if there are earlier restorations; these will appear as dark areas.
When the conservators embark on restoring a painting they begin by removing the old varnish. This makes any earlier restorations to the painting more clearly visible and shows the conservators how to approach their work. While they carry out the cleaning process the conservators use a small UV lamp in order to check the evenness of their work.