Decorating my sons (2.5 yr old) room and suddenly had a thought...
He love glow-in-the-dark things. Ceiling is covered in sharks and
cows (don't ask) that glow in the dark for a while when they have
been exposed to bright light for a while. You know the type - they
are plastic and a sortof yellow-green colour.
When you see these things for sale in shops they are often glowing
brightly under some sort of UV (AFAIK) light. Now all I remember
from my electronics/physics days is that UV light is not good and
that eprom erasers shouldn't be looked at. This is obviously different
to the UV that I see in shop displays (UVA and UVB rings bells...).
What I would like to do would be to get a normal cheapo uplighter.
stick it to the wall and stick a UV bulb into it. Something like
KJ64U from maplin.co.uk for example.
Will this work? If so is it a sensible idea or are there bad things
likely to happen with this much UV exposure (i'm guessing that this
is nothing compared to the suns output).
If it won't work then can anyone suggest something that would? I know
the shop displays use some sort of flourescent tube but ideally I would
like to be able to dim this light using a normal dimmer switch (I
assume there would be no problems with this?). I'm looking at flooding
the ceiling really although if I could just light the room in UV with
no side effects then even better!
Anyone else done something similar?
There`s a site somewhere (linked from an advert on www.filesoup.com IIRC
but I can`t see the advert there atm) where you can buy some sort of
flourescent paint which is practically invisible under normal light, but
looks great under UV ;-)
Failing that, there`s always something like...
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First of all, do make sure your black light can't be looked at straight.
It will lead to conjunctivitis with prolonged exposure.
Fluorescent paints are available. I suggest you google on 'black light';
and Disco effects' and so on, because thats where we used to use it.
Dayglo paints sometimes are UV reactive. Craft shops stock em.
Firstly Ultraviolet light does damage eyesight. It can cause blindness
if misused, and it it very easy to misuse it without reailsing what
one is doing. Real uv is not something I would be putting in a kids
Pointing the thing upwards is obviously not going to work, as kids are
inquisitive, and he/she will climb up and peer into it, eyes wide open
in the dark, and all of 6" from the light.
Some types of UV source are real nasty, some are much less so. In
short this plan is not a good one.
What is less well known is that flourescent and phosphorescent things
do not require UV to glow, all they need is a light with a higher
frequency colour than they emit. So something that glows yellow or
green would work well with blue light. Blue ilght, unlike uv, is safe.
It is thus the obvious choice.
Blue filament bulbs are very inefficient, blue fluorescent tubes are
Fair enough. I take it that disco lights and the things on glow-in-the-dark
displays in shops are UV but rely on the fact that people are not looking
at them for hours on end (although I wonder how shop workers stand on
this...). Or maybe they are not UV after all - they certainly looklike
it and they give out very little visable light.
Is something that is used in disco lighting likely to be ok or are
these things just "less bad"? I noticed that one of the Safeway stores
in Canterbury now uses UV lighting in the loos (and this is not to
make things glow :-) - again, I guess it isn't somewhere you would
be hanging around for long.
Interesting. Maybe I will take a look at the lights that are meant to
be fitted in PCs - nice and small and reasonably cheap.
email@example.com (dmc) wrote in message wrote:> >Firstly Ultraviolet light does damage eyesight. It can cause blindness
Disco blacklights are lowest frequency uv plus visible violet, and are
low power, the light source is spread out along the length of a low
power tube, and there are warnings to mount them so they arent seen
directly, to use them for limited times, and to use them with other
lighting on. These warnings are not necessarily all heeded of course.
At the other end of the scale there are uv sources that are short
wavelength, intense, and accompanied by no visible light. Sources ilke
this can cause immediate blindness. I've worked with 1.6kW uv sources,
and before I was there, there was someone who caught a glimpse of the
arc and was [temporarily] blinded instantly. He got to see again later
that day. Believe me, uv sources like that hurt!
The problem with using a blacklight in a kids room is that the kid is
not going to take any notice of the safety issues, and will probably
stick their nose on it sooner or later, with dark-accustomed eyes. The
result can be swelling and inflammation of the back of the eye,
temporary blindness, pain, and detachment of the retina from the eye.
Its known as snow-blindness, and it is possible for it to cause
permanent and considerable damage.
Far less bad than some sources. But, see above.
you cant see ultraviolet, its invisible. I dont know what they've got
but it might well be violet rather than ultraviolet.
Its not in the best bit of Canterbury but still surprised me that they have
had much of a problem there. Still, despite the signs claiming that this
is UV lighting it is a faily deep violet colour.
Fair enough. I think I am convinced that this is not a smart idea.
Interestingly, I was in Woolworths this morning and they are selling
a "UV" cd rack. This is a fluorescent tube that glows a deep purple
in the middle of a load of plastic that "glows".
Also,away from the tube idea maplin are selling a "black light UV bulb"
that fits normal ES or BC fittings. The chap in the shop reckons that
it is a normal 75 watt bulb with glass that just filters all but the
violet and UV end and that the UV from it is no worse than the UV from
any normal lightbulb. The blurb on the website states "A standard size
light bulb with a special coating that produces a deep purple light and
large amounts of Ultra Violet light"
Which is most likely? I assume that there are magic coatings that could
convert visable to UV in which case this is not a good idea. If however
it really is a normal bulb with a filter then I guess its no worse than
any other bulb would be. Code KJ64U for example.
Blimey. 1.6kW visable source would be pretty blinding I would have
thought! Out of interest, can I ask what this sort of intensity UV
was being used for?
It would actually be near impossible for current child to access it - it
would be 7 ft up in an alcove that is not visable from below at all. As he
is only 2.5 yrs at the mo and there is nothing to climb on its not a major
issue at the moment. I still think that I will pass on the idea though :(
It says UV on the door but is a fairly dark violet colour. I take it that
this is perfectly safe then (assuming it is all visable violet)? If so,
are violet tubes available at reasonable price anywhere? Maplin seem to list
normal tubes and UV tubes but nowt in between. They do have coloured cold
cathode tubes for PC mods though - I may have a play... :-)
1.2kW visible is almost the standard lamp in my industry. The largest
I have worked with was 10kW, two of them, now that *was* bright and
These are halogen arc lamps (HMI) used in the film/TV industry to
match daylight colour temperature and lumen levels.
1.6kW of UV sounds lethal to anything in range to me. Sterilisation of
Dave. pam is missing e-mail
Hi. They were carbon arc parabolic reflector focussed beam lights,
1.6kW arcs. Not 1.6kW of uv, but still enough uv to blind instantly if
you caught them unfocussed, and I expect they'd blind permanently if
you got caught up with the focussed beam.
One part of the construction was open so you had to be _very_ aware of
where you walked. I think the H&S people would wet themselves
I think "blacklight" tubes are what you are after, which as far as I
know, are perfectly safe, having had all the harmful wavelengths
filtered out in the lamp coating. Our local B&Q warehouse sells them,
they fit in standard fluorescent fittings. The light is a fairly deep
blue/violet colour and causes things to fluoresce.
The "UV" incandescent lamps are a bit feeble to say the least. You only
get the very small amount of UV which all incandescent lamps produce.
Yep - I am pretty sure now that that is what I want. What I am still not
entirely clear on is how safe these are. Some people seem to say no - loads
of people say that they are fine. Unfortunatly, most of the places that
claim they are fine are places selling them so they have interest!
As there is so much doubt as to their safety I think I'll give up :(
Thats interesting. I hadn't even considered that B&Q might have some - I
was looking to mail order. I will pop in and have a look at what the
packing says - if its got dire health warnings then I suspect its game
firstname.lastname@example.org (dmc) wrote in message wrote:> Also,away from the tube idea maplin are selling a "black light UV bulb"
sounds quite doable. Standard filament bulbs are extremely inefficient
at producing uv. I have seen violet filamet bulbs before, but they
dont produce much of anything. Theyre very dim even in violet, let
alone uv. Theyre used in el cheapo flykillers. White bulbs are just as
effective, but of course people will pay more for something that looks
more like a proper flykill unit.
no, you can only go from shorter to longer wavelength.
true if used under the same lighting conditions, with the same amount
of shading. But if used in the dark, with eyes wide open, not so. But
ordinary filament bulbs produce so little uv I doubt theres any
concern even then.
yup, accepted. the only problem with that argument is that kids have a
tendency to do things long before their parents think its even
ok, probly is then.
if its low power, spread over a tube's area, low ferqwuency uv, and
used in a well lit room with people only spending limited time there,
then it will be perfectly safe. Course I'm assuming they havent got
1.6kW of it going :)
Long time since I bought any out of the ordinary tubes, and I've
tended to use either halogens or mercury arcs for uv. For most tube
type apps, halogens are cheaper and easier.
Just had a quick play with low powered(?) UV source and No.1 Daughters
bedroom (she is away...) which has a few glow-in-the-dark stars an
moons. The UV source was a battery powered security type (came with a
couple of UV flourescent marker pens).
The things that really kicked off contained optical brighteners (white
photcopier paper etc). The glow in the dark things didn't show from a
distance but the UV lamp when bought close really charged them up
As to the amount of UV coming from this lamp I haven't a clue. Nor
about any problems of long term exposure.
Dave. pam is missing e-mail
Thats because they work by absorbing light in the visible spectrum and
re-emittining it later. I have a T-shirt like this.
That's not fluorescence, its summat else.
True fluorescence is from phosphors and other strange chemicals. They
aborb UV and re-emit visible. Paint loaded with that glows under UV.
I wish you took my advice to google
What you want is here
and so on ad nauseam
Just google on black light fluorescent paint.
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