Effects of Light Exposure
Light is a small part of the
electromagnetic spectrum to which the eye is sensitive. Its presence is
essential for the most rewarding perception of almost all art. Yet
exposure to light can result in cumulative and permanent damage to
light-sensitive objects. Low light levels over a long period of time can
cause equal or even greater degradation as intense light for a short
period. Damage occurs because light is radiant energy. This energy
causes irreversible change, either through radiant heating or
photochemical action.
Radiant heat may create a rise in temperature that causes a reaction on the surface of an object, such as cracking, lifting, and change in color. Photochemical action is a chemical change at the molecular level and is the more profound transformation resulting from the exposure to light. The most potent sources of these destructive energies come from just beyond the limits of visible light—ultraviolet (UV) and infrared (IR) light (fig. 1). The longer wavelength, infrared, is a common source of radiant destruction. Ultraviolet rays, with their shorter wavelength, can be a significant basis for photochemical destruction. These wavelengths should be filtered and eliminated as much as possible to prevent damage. Visible light is essential for the perception and appreciation of art, but it, too, contributes to degradation and damage of objects. Irreversible damage caused by light can include color fading, yellowing, and embrittlement. Since all damage is cumulative and irreversible, the duration and intensity of light exposure should be carefully monitored and limited.
Radiant heat may create a rise in temperature that causes a reaction on the surface of an object, such as cracking, lifting, and change in color. Photochemical action is a chemical change at the molecular level and is the more profound transformation resulting from the exposure to light. The most potent sources of these destructive energies come from just beyond the limits of visible light—ultraviolet (UV) and infrared (IR) light (fig. 1). The longer wavelength, infrared, is a common source of radiant destruction. Ultraviolet rays, with their shorter wavelength, can be a significant basis for photochemical destruction. These wavelengths should be filtered and eliminated as much as possible to prevent damage. Visible light is essential for the perception and appreciation of art, but it, too, contributes to degradation and damage of objects. Irreversible damage caused by light can include color fading, yellowing, and embrittlement. Since all damage is cumulative and irreversible, the duration and intensity of light exposure should be carefully monitored and limited.
For additional resources and further information, including tips about caring for your own collection, please refer to the sources below.
Web Resources
American Institute for Conservation of Historic and Artistic Work http://www.conservation-us.org/
Library of Congress http://www.loc.gov/preservation/care/
Smithsonian Museum Conservation Institute www.si.edu/mci/english/learn_more/taking_care/index.html
Canadian Conservation Institute http://www.cci-icc.gc.ca/index-eng.aspx
No comments:
Post a Comment