On Mon, 12 Oct 1998, Meeker, Amanda wrote:

> drawback appears to be the high cost of the lamps (they run $30 apiece
> around here), and the relatively short lamp life (though having them on
> dimmers does help significantly there).

As someone who uses theatre equipment every day here are two brief
thoughts on the above:

First a hint: Most theatre fixtures today use quartz-hallogen lamps. One
feature of these is longer life than lamps of earlier design. The longer
life comes from a chemical process that requires very high heat (I won't
bore folks with the details). This is why these lamps are so small, so
that the heat will be higher in the envelope. When you dim these lamps
they do well from the light perspective but the dimming would also
(depending on the amount) circumvent the regenerative cycle requiring the
high heat. The good news is that running the lamps to full every once in a
while will allow the lamp to do its stuff, restoring the tungsten back to
the filament.

The other point though is that with the higher heat of the quartz lamps
comes more efficience as realized by more UV from these lamps. For artwork
this would require a bit more thought in the usage of these fixtures. It
is not as bad as the UV from fluorescent lamps but significant enough for
actors to worry about skin and eye conditions.

Richard Finkelstein
Head of Theatre Design and Technology
U of Colorado at Denver
School of the Arts