Lighting for copy photography

In reply to W.T. Chase, regarding series/parallel lighting for
modelling: I seem to recall that, when this discussion began, the
problem was to construct a copy stand setup for public use.  If this
is the case, a better solution might be to use the tungstens on a
variable voltage transformer--a potentiometer, that is--to allow
continuous, infinitely-variable illumination.  This would not only
address "modelling", but also answer the problem of users bringing a
variety of equipment and film speeds to the stand: different light
levels will be more practical with different films and, as pointed
out by Chase, running at reduced voltages will greatly extend lamp
life.  There could be small problems with color temperature
variation at different voltages, but I don't know how exacting the
users are likely to be in this regard.

Chas. Stewart
Sr. Photographic Technician
LPS, U.C., Berkeley

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                  Conservation DistList Instance 12:84
                   Distributed: Tuesday, May 4, 1999
                       Message Id: cdl-12-84-002
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