LED lights in exhibition cases

Karen Potje <kpotje [at] cca__qc__ca> writes

>For the same CCA exhibition described above it has been suggested
>that we use white LEDs on the *inside* of an exhibition case as the
>light source for a display of documents.  UV light must be excluded
>and the light level must be low (50 lux).  Is information about the
>UV content of white LEDs available?  Is it possible to control the
>light levels and ensure that they remain at a steady 50 lux  over
>the course of a long (8 month) exhibition? Do LED lights start out
>bright and then get dimmer over time?  The designer of the show
>suggests that LEDs are cool--there will be no heat build up in the
>completely enclosed exhibition case.  Is this the case?  Are LEDs
>being used by other museums to light exhibition cases?

We are investigating LEDs for use in lighting our doll houses that
are currently undergoing conservation treatment. In general, they
are still too "blue-white" for our taste, we would like a tungsten
light temperature of around 3400K. Some manufacturers claim they can
do this, but we have not yet seen any samples of this color
temperature.

They are quite bright, and dimmers are just being developed. They do
generate heat, but not a lot. Watt for watt, the heat seems to be
similar to tungsten bulbs, but that is just from holding a one-watt
LED between my fingers for a few minutes. Also, a one-watt LED seems
to emit more about as much light as a 5-watt tungsten nightlight,
but we are still conducting measurements with a data logger.

The big advantage is that they have a very long life, an estimated
10-15 years of daily use at our museum that is open 6 months a year.
There is some UV, but not much on the LED's we have tested. From all
our informal research and conversation with several developers, I
believe that LED's are the future of in-case lighting (which
sometimes cannot be avoided) and probably lighting in general. But
widespread use is probably 5-10 years out. At this point, be
prepared to be the test-case if you decide to use LED lighting, and
therefore expect the unexpected in heat build-up, bulb life, etc.

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 17:6
                  Distributed: Thursday, June 26, 2003
                        Message Id: cdl-17-6-004
                                  ***