Are we forgetting that light intensity is also harmful to sensitive
materials, such as paper and fabric?  Not only do you have to protect your
collection from the damaging effects of ultraviolet radiation, but lux
should be carefully monitored so that fading and embrittlement do not
occur.  While we may be able to mitigate UV damage with filters and
sleeves, a print or watercolour (or banknote) will still fade if the well
filtered light is too intense!

As my professors used to tell us: Light damage is cumulative and
irreversible.  The Canadian Conservation Institute publishes notes and
technical bulletins which outline collections care and preservation, such
as proper lighting conditions. A light damage slide rule is available for
purchase, which will tell you how much damage is being done to your
artifacts from both UV radiation and lux.  They can be contacted on the web
at:

http://www.pch.gc.ca/cci-icc/

The slide rule is listed under Products and Publications

- S7E Light Damage Slide Rule - $20.00
          A basic care-of-collections tool to which museum staff may refer
to determine the intensity and duration of
          illumination that will best preserve the colour in artifacts for
as long as possible. Slide rule and instruction booklet.

Alex Avdichuk
City of Toronto
[log in to unmask]

______________________________________________________________________
How about using fluorescent tubes with UV sleeves?  Its low heat, low cost,
bright white light and with the UV sleeves, there should be no harm done.
Just remember that the UV sleeves are essential.

Mike Highfield


>Could anyone comment on the use of halogen lights in a display case for
>bank notes. Will this cause problems? What are the alternatives? Thanks
>
>V. Manalo



We recently purchased TL 70 series fluorescent lamps (bulbs and tubes) for
our museums and will be used in all of our exhibit spaces. I asked the
manufacturer, Philips Lighting, what the UV output of these bulbs are and
they answered "The UV wavelength is 400-700 nanometers which is visible
light." The problem is that the museum literature I have on lighting refers
to "microWatts per lumen" or mW/l.  Does anyone know how to calcuate the
nanometers into mW/l so I can really understand how much UV is being
emitted by these new bulbs? I assume that I need to put a UV filter over
each bulb. Thanks for any help!
Mary Ames Sheret
Curator of Collections/Exhibits
Southern Oregon Historical Society