>Are these the generally low voltage ( 6 V ) tungsten lamps often used in the
>home as spot lights and in headlights ?
>I have also assumed that tungsten UV ' health' lamps work by filtering out the
>unwanted 'light' which results in low UV output and high heat. Are there any
>other significant factors ?
There are some types of low voltage halogens (6-12-24 V) for home and
exhibition use: these types had a "cold" mirror around the lamp. This
mirror reflecting the visible light but not the IR or UV (these light
are transmitted). However the direct radiation is unfiltered in these
lamps but the remainder of UV/IR is usually enough weak for average case
(not recommended for continuous lighting of photolitic silver made pictures:
all POP especially salt papers, untoned materials, albumen, etc.) Gum:
up to the durability of the used colorant. You can test a sample.
I suggest an UV meter instead of the description of producer to control
the true amount of UV/IR or at least the 40 lux maximal energy on the surface
of lighted object. A possible alt-control tool a piece of POP in the light of
this lamp: when the paper is darkening while a few hours the lamp is wrong
(too much UV). To cover a part of this POP material with a piece of black
paper is suggested because the naked eye cannot to see the changes without
an ethalon. The simple IR control is a thermometer on the lighted surface:
when it's too warm: the IR radiation is too strong.
Balint
- Balint Flesch - Archaist/conservation photographer. - Budapest/Hungary. -