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Asunto:[gr_mulhacen] ULTRAVIOLETA
Fecha: 25 de Marzo, 2001  18:04:56 (+0100)
Autor:Frank \(Moderador\) <fmsolaf @.......com>

Me he dado una vuelta por esta página que creo interesante, sobre todo para los
que esten interesados por los fluorescentes.
El inconveniente es que está en inglés, pero creo que es interesante.


He copiado la parte que me interesa, por si alguien puede/quiere traducirlo.


http://www.uvminerals.org/photog.htm

Long wave: 
     These lamps come in four forms: blacklight, mercury-vapor spotlights,
induction lamps and halogens. 

     Blacklights are fluorescent lamps that are filled with mercury vapor. The
tube is made of Woods-glass coated on the inside with a
     phosphor. The short wave emission lines of the mercury vapor's spectrum
excite this phosphor and cause it to emit long wave UV. The long
     wave passes throught the glass and is emitted from the lamp while the short
wave is blocked. 



Short wave: 
     Photo #4 - Again the same aragonite specimen as seen in the long wave
section but this time under
     short wave UV. The source is a well filtered germicidal lamp. Collection
and photo: © Axel
     Emmermann.
Practically all short wave UV sources are based on the spectrum of mercury vapor
in fluorescent
     lamps. All of these lamps have one thing in common. They are made of fused
quartz and therefore
     somewhat more expensive than other fluorescent lamps. The reason for this
is simple; glass won't
     transmit short wave UV. Lamps like this are often used to disinfect the air
in government buildings.
     They come in all sizes, ranging from small 4-watt lamps up to full sized
40-watt tubes. This UV source
     emits a weak blue light that must be filtered out. A normal short wave
-filter will do since these lamps don't emit much heat. To get more of
     the UV on your specimen, you'll have to use a reflector. Don't use glass
mirrors or polished sheets of metal, they will either absorb the short
     wave UV or turn it into photoelectric energy. Aluminum foil will do the
job.
There are several short wave UV sources readily available from quite a few
manufacturers. The only one I have seen and tested is the
     SuperBright 2000SW. It has an amazingly powerful UV-output. If you want to
photograph specimens that fluoresce rather weakly, this is
     the one you must have. If you use it, take care to select an absolutely
non-fluorescing background or create a large enough distance
     between specimen and background! Almost anything will fluoresce under the
SuperBright's power! Make sure to protect your eyes and
     skin, and ventilate your workspace because this lamp produces a lot of
ozone.

     If you haven't enough space to set up your lamp or if you don't want to
spend too much money on purchasing one, you might want to
     consider an induction lamp. They are usually known as "economy" or
"energy-saving" lamps that come in double U-shaped quartz tubes on
     a regular socket with built-in electronics. You'll need the "germicidal"
type (see fluorescent lamps). This lamp also requires a filter and
     aluminum reflector.


http://www.uvminerals.org/photog.htm


Un saludo.




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