For task lighting, especially in an art library (where patrons
will be looking at images, slides, swatches, etc.), fluorescent
light has two big drawbacks: "flicker" and color distortion.
Flicker can be minimized by making sure the light fixtures have
high-frequency electronic ballasts -- which is a bit confusing
because you also want those ballasts to emit very low EMFs or
electromagnetic frequencies. (Magnetic ballasts, with high EMFs,
are the kind that buzz and strobe and even make people ill,
so avoid them.)
Color distortion can be lessened by using full-spectrum
fluorescent tubes, or tubes with a Color Rendering Index (CRI)
near 100. Full-spectrum tubes will be more expensive than
normal tubes, though.
Fluorescent light is cheaper and cooler than incandescent light,
which seems good for the bottom line. However, fluorescent bulbs
emit a lot more ultraviolet radiation, which can hasten the "slow
fires" of paper degradation in books. Although sleeves can be placed
over standard fluorescent tubes to filter out the UV, you might not
be able to get sleeves small enough for a tabletop light fixture.
Actually, though, you probably will have so few of these fixtures
that UV won't be an issue. Your museum's conservators could
advise you on that. (Interestingly, some light bulbs and tubes
advertised as full-spectrum actually block the UV end of the
spectrum -- Verilux is one such brand.)
It might be easiest just to go with regular incandescent light
fixtures. Most incandescent bulbs have a CRI of at least 95,
so you get your true color perceptions. Flicker isn't an issue
with normal light bulbs. And if you only have a few lamps,
then the bulbs in them shouldn't generate much heat, nor
should they cost very much to operate. The building
engineers working on your construction project might be
able to tell you the relative energy costs of incandescent
task lighting, and whether it can appreciably affect ambient
temperature.
A couple of good general web sources about lighting are
http://hem.dis.anl.gov/eehem/94/941116.html by Home
Energy magazine, and www.nrc.ca/irc/practice/lig3_E.html
by the Canadian National Research Council. The Conservation
DistList archives unfortunately don't seem to contain much
on the topic of task lighting (as opposed to overhead or
exhibit lighting); there is one posting about studio lighting
that seemed relevant.
--K.A. Bayruns
Seattle, WA
At 11:22 AM 3/13/02 -0600, you wrote:
>The Nelson-Atkins Museum of Art is in the final design phases of an
>expansion project which will house a new library facility. The architects
>have proposed fluorescent task lighting mounted on the tables for the
>library's reading room.
>
>We would appreciate comments concerning this type of lighting design and its
>use in art libraries.
>
>Thank you.
>
>Cindy Barth
>Head Librarian
>The Nelson-Atkins Museum of Art
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