[Rockhounds] Telling the UV from the Lamppost.

[Axel Emmermann]

Ok, this calls for the "definitive" answer... ;-)))

Take something that will fluoresce in either LW or SW UV.
Try grey or blue paper with fluomarker painted on.
Put it behind a glass plate.
Shine you UV lamp through the glass.
If the object fluoresces you have a long wave lamp.
If the glass fluoresces and the object doesn't, you have a SW lamp.

Make sure that the glass is glass and not some acrylic plastic.

Glass blocks SW-UV but allows LW to pass.

There, I said it ;-)


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 jb
> Verzonden: donderdag 14 mei 2009 6:02
> Aan: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
> Onderwerp: Re: [Rockhounds] Telling the UV from the Lamppost.
> 
> jb wrote:
> > Kreigh Tomaszewski wrote:
> >> If it makes a postage stamp glow it is short wave.
> >>
> >>
> >>>
> >>> I have a UV light with no markings.
> >>> The tube itself has no markings.
> >>> I have no immediate access to reference material that may be of any
> >>> help. So...
> >>>
> >>> What is the best way to determine what frequency the lamp is?
> >>>
> >
> > So far this answer is the one that makes the most sense. This is a
> > specific technical application with specific known characteristics,
> > utilizing UVC.
> >
> > And (first class) postage stamps are likely to be almost anywhere. The
> > glow is green with a short phosphorescence afterwards.  And if somehow
> > I came across an old air mail stamp, the glow would be red with the
> > same short afterglow. Most of the papers in modern stamps is also
> > fluorescent (usually some shade of white) but that would not be
> > definitive as to which UV I have.
> >
> >
> > john
> >
> 
> P.S. The fluorescence is used to distinguish between stamped and
> non-stamped mail. the phosphorescence is used as a trigger to cancel the
> piece. All this happens at a rate of  36000+ letters per machine per
> hour.  Often a "hot" envelope (usually but not always a red or pink
> colored one) will also trigger the cancellation even if it does not have
> a stamp.
> 
> U.S. and foreign currency also have specific UV characteristics, but
> these may not always be known. Still it would be instructive to try the
> light on a $5 bill taken from one's pocket. I think most of the
> distinguishing characteristics are UVB because those are the most
> commonly available detectors to merchants and others.
> 
> 
> john
> 
> --
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