Lighting and oil paintings

In response to Roxanna Herrick's inquiry about an oil painting exposed
to excessive light, the easiest and least expensive way of protecting
this valuable painting really is to move it to a safer location. The
dangers are 3-fold: exposure to ultraviolet light, which is the most
damaging wavelength, exposure to overly intense illumination (of any
wavelength), and heat from the direct exposure to sunlight and warming
of the brick wall.

The ultraviolet component could be controlled with filters on the
windows (all of the windows), or a u.v. filtering glazing (glass or
plexiglas) over the painting. The former would be fairly expensive, and
the latter may interfere with the appearance of the painting by creating
distracting reflections.

Even with the u.v. eliminated, the light levels may simply be too high
to avoid eventual damage and fading of at least some of the pigments. To
lower light levels, the windows could be curtained, or tinted films
applied to the glass.

Reflective tinted films (such as are sometimes applied to office
buildings) could help to reduce both light levels and heat gain, but
would definitely alter the appearance of the building.

Unfortunately, we cannot change the nature of materials and their
response to adverse lighting conditions. The best approach is to avoid
such conditions whenever possible.

Jane Ketcham
Conservator

                                  ***
                  Conservation DistList Instance 8:74
                  Distributed: Thursday, March 9, 1995
                        Message Id: cdl-8-74-009
                                  ***