Effect of light on fine art materials

Frank A. Reynolds <fr0c [at] andrew__cmu__edu> writes

>In the same manner that age acceleration tests are conducted on
>photographic materials, have there ever been any studies done on
>fine-art support materials and paints?
>
>I am interest in knowing whether the wattage, or the color
>temperature of a lamp, is the more detrimental factor.  And if
>fluorescent lamps are less harmful than tungsten lamps?  Actually we
>are trying to determine the effect of color scanners on artworks and
>such information would be helpful when considering the light sources
>used in different models.

Light certainly takes part in the degradation of materials, as it
provides energy for chemical reactions. How much energy depends on
the wavelengths of the light: the shorter the wavelength, the more
energy. Therefore the UV component of daylight and other
light sources is the most damaging component. Fluorescent lamps emit
a variety of wavelengths, according to the type and manufacturer.
Some manufacturers will supply information on the spectra of their
tubes if asked. The variety in wavelengths is (not always) visible
in colour differences. Tungsten lamps emit a fair amount of yellow
and red light (and warmth), but less UV than most fluorescent lamps.

The detrimental effect of light depends not only on the wavelengths
but also on the intensity of the light and the length of exposure.
Another point to consider is the mechanical side of the scanning
process. I must confess I have never scanned anything, but I would
like to stress the importance of paying attention to any possible
sources of mechanical damage to the art works.

I have come across two useful publications related to this subject:
"A Suggested Exhibition/Exposure Policy for Works of Art on Paper"
(http://www.webcom.com/~lightsrc/policy1.html), and
"Ultravioletafgifte van fotokopieerapparatuur en elektronenflitsers"
by Dr. J.G. Neevel, available at the Netherlands Institute for
Cultural Heritage in Amsterdam.

I hope this helps.  I think it is very important to think about  the
effects of new developments and am looking forward to more
information on this interesting topic.

Robien van Gulik
Teylers Museum, The Netherlands

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                  Conservation DistList Instance 12:56
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