Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: Blacklighting
References:  <[email protected]>
From: Tomi Holger Engdahl 
Date: 01 Mar 2001 21:41:27 +0200
Message-ID: 
Organization: Helsinki University of Technology, Finland
Lines: 29
X-Newsreader: Gnus v5.6.45/Emacs 19.34
[email protected] (Frank Wood) writes:

> >The "blacklight" filament lamps are very difficult to find in the UK.
> >The Gadget Shop sold them briefly and they are available from various
> >Skytronic distributors.
> >
> >The US has a lot of nice gadgetry stuff that we don't have over here.  I
> >particularly liked the PL style compact fluorescent blacklights.  Stuff
> >like this is dirt cheap in the USA compared to here.  If someone from
> >the States mentions the price they are paying for a 4' UV tube you will
> >see what I mean.
> 
> There is no way that there is such a thing as a "blacklight" filament lamp. Not
> difficult, Impossible!

You are definately wrong! I happended to own such bulb
(not very good blacklight source, but was something).
Normal filament lamps can produce some ampund of UV when the filament
runs very hot (for example the filaments of halogen lamps produce
UV). Usually the UV is filtered aways with the outer glass of the bulb
because that UV is not wanted. If you take a bulb with hot filament,
repalce the glass with somethign which passes UV (quarz glass for example)
and put a filter which only passes UV light, you get a blacklight.
Effiency is not very good, but you have blacklight.

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/