[Rockhounds] Telling the UV from the Lamppost.

[Axel Emmermann]

No, probably plastic. 
There are more plastics that Block UV than there are that let it pass...
The main advantage of those safety goggles is that they fit closer to your
face. Normal glasses don't protect against UV from above and aside.

Cheers

Axel Emmermann
European Regional Vice President of the
Fluorescent Mineral Society
<http://www.uvminerals.org/>
=========================
Mineralogische Kring Antwerpen/Antwerp Mineralogical Society
<http://www.minerant.org/index.html>
Werkgroepleider/Workgroup leader: Fluorescerende mineralen/Fluorescent
minerals
Technische Realisaties/Engineering
My website: http://users.telenet.be/axel.emmerman/FiatLux/Index.php
 
 
> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com
[mailto:rockhounds-bounces at lists.drizzle.com]
> Namens Tom Bowers
> Verzonden: vrijdag 15 mei 2009 23:54
> Aan: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
> Onderwerp: RE: [Rockhounds] Telling the UV from the Lamppost.
> 
> So, those folks who sell safety glasses for viewing shortwave fluoresence,
are those just
> normal glass lens glasses?
> 
> --- On Fri, 5/15/09, Axel Emmermann <axel.emmermann at pandora.be> wrote:
> 
> 
> From: Axel Emmermann <axel.emmermann at pandora.be>
> Subject: RE: [Rockhounds] Telling the UV from the Lamppost.
> To: "'Rockhounds at drizzle.com: A mailing list for rock and gem collectors'"
> <rockhounds at lists.drizzle.com>
> Date: Friday, May 15, 2009, 2:45 AM
> 
> 
> 
> >
> > All glass?
> 
> [Axel] Yes, except the kind of glass that the bulb is made of. That's
> barium-silicate glass, designed to pass UV and quite expensive.
> 
> 
> > I have a SW UV bulb with no markings other than "Japan" that was made in
> > the 1960's. It looks to have been made of glass with two filaments
> > inside. The filaments have a whitish glow next to them when 120v is put
> > to them
> 
> [Axel] If you can see the filaments when the lamp's off it's clearly a
> short-wave.
> 
> > and the light is passed through a special filter, which looks to
> > be made of some very dark purple crystalline material, for the SW UV.
> 
> [Axel] That would be a UV-diaphanous filter. If it's from the 60's it is
> probably an old type that suffers from solarisation easily and has a
limited
> lifespan. Does it still perform?
> 
> > The shape of the bulb is like that of  the other in the lamp, a standard
> > F4T5-BLB LW bulb.
> 
> [Axel] a 4 watt? How large is the filter?
> 
> > Your answer is good and I accept it as a general pretty good one as the
> > fact that UVC does not penetrate ordinary window glass is a good
> > distinguishing characteristic. And ordinary window glass can be found
> > almost anywhere.
> >
> > So the answer would appear to me to be:    1. find something that will
> > fluoresce.  2. Put it behind some ordinary glass and see if it will
> > still fluoresce with the same lamp.   3. Yes = LW; No = SW.
> >
> 
> [Axel] Yes, Houston we have lift off ;-))))
> 
> You're welcome
> 
> Axel!
> 
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