Lighting

Isabel Medina <ismedina [at] yahoo__com> writes

>I am evaluating lighting options for in situ conditions. I am
>comparing fluorescent contra LED lighting, since I am in need of a
>non-incandescent lighting that can be used in high humidity
>locations (close to 100% RH) to illuminate stucco panels made of
>lime mortars and painted with inorganic pigments and (perhaps) an
>organic medium. LED is a new technology. I know about its durability
>and economy. I have not been able to find any information about its
>uses in our field.

We have been working with an LED lighting products company named
Prolume for the past two years to develop an LED case light that can
be safely used inside exhibit cases that contain sensitive
materials, in our case a large collection of dolls, automatons, and
toys. We have had significant success illuminating artifacts on
shelves that are 8 inches to 30 inches apart and 10 inches to 24
inches deep. Depending on the spacing of the LED's in the LED
Illumination Assembly (LIA), we can achieve readings on the
artifacts of 30 to 250 lux. These LIA's consist of LED's mounted in
a 5/8 X 5/8 inch square tube housing and are custom manufactured in
any length from 4 to 48 inches, although we usually use 1-foot to
2-foot lengths.

We estimate that the LIA's will last for over 20 years, operating 7
hours a day for six months a year. The LIA's run very cool, emit no
UV because of their polycarbonate lens, use about 1/3 the power of
fluorescent bulbs, and are priced about the same as the small,
designer fluorescent units. They are significantly less expensive
than fiber optics and give a more evenly distributed light that can
be conveniently aimed directly at the artifact or at the floor of
the case, raking over the artifact to provide lower light levels.

They are available in several different color temperatures, from a
warm 3000 K (similar to MR16s), to a cool 4000K. We have determined
that a 3500K is the most pleasing color temperature for our
artifacts, giving good color rendition. We have installed about 200
of the LIA's and are very pleased with their performance. Please
contact me off list for additional information.

Richard L. Kerschner
Director of Preservation and Conservation
Shelburne Museum
PO Box 10, Route 7
Shelburne, VT  05482
802-985-3348 Ext 3361


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                  Conservation DistList Instance 19:7
                  Distributed: Thursday, July 21, 2005
                        Message Id: cdl-19-7-003
                                  ***