Re: Tungsten and Mercury light

SCHRAMMR@WLSVAX.WVNET.EDU
Fri, 11 Oct 1996 10:29:04 -0400 (EDT)

Terry,

You have asked a lot of questions I cannot answer since I do not have
access to the technical data. However, let me tell you what I do know.
My statements were about high or low voltage halogen bulbs which, although
are considered tungsten bulbs, do produce more UV light than an ordinary
tungsten lamp which does not produce significant amounts of UV. This is
based on knowledge which comes to me through my connections as an archivist.
Museums and archives avoide UV light as much as possible. In the archives
and museum that I manage, the overhead fl bulbs are all covered with UV
filters. The photographs which are on display have an additional UV filter
along with glass in the frame. When the halogen bulbs first came out in
this country, archivists and museum curators were warned via newsletters
etc. of the danger of using them because of the amount of UV light they
produced. Usually, when we get a warning like this, it means that someone
at a large institution has done the necessary testing. The Amercican Archivists
Association is a pretty reliable bunch, but as I have mentioned before,
they are worrywarts and tend to be pickey because they are thinking in terms
of long-time preservation techniques. Nevertheless, I would not want any
of my work displayed under halogen lights for very long unless is was
platinium or black i.e. monochrome gum. Cyanotype and Kallitype would
probably be unhappy under these lights. Maybe someone on the list has
some technical info on these halogen bulbs.

Bob Schramm