# HID Blacklight



## PhotonWrangler (Oct 25, 2003)

Anyone ever used one of the Philips 175 watt mercury-vapor
black lights, the one made out of black-light-blue glass?

I bought one years ago to use as a light source for
Halloween and other effects lighting, but it seems
to be dim. I bought the recommended ballast and
capacitor, so it should be running at it's optimal
voltage and current, but it seems that the lamp
is made without the internal blue phosphor coating
that fluorescent blacklights (and bug zapper bulbs)
are made with, and the direct output of the ionized
mercury vapor doesn't seem to have a lot of output
in the near-UV range.

Has anyone else used these? Am I missing something?

/ubbthreads/images/graemlins/confused.gif

pw


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## JSWrightOC (Oct 30, 2003)

Mercury vapor discharge lamps put out a LOT of UV light. This includes streetlights, unless they are filtered. To the best of my knowledge bug-zapper tubes simply have a frosted coating inside to diffuse the light. I have seen low-pressure mercury vapor lights that are the same overall design and dimensions as a fluorescent lamp, but with no coating at all, phosphor or otherwise. It was used in a sterilizing cabinet for lab saftey goggles. Its light output looked just like the output of a bug zapper tube, except you could directly see the ionized gas. It has that ghostly blue-ish glow that has "volume"...ie, the thicker cross section of gas from your POV was brighter.

"Fluorescent" blacklights (I say that because technically it isn't fluorescent, not utilizing a phosphor or anything /ubbthreads/images/graemlins/tongue.gif) simply have a violet filter painted on the tube or pigment in the glass to block out most of the visible light. The fill gass is the same as standard fluorescent lamps, I believe--it would almost have to be for them to be drop-in replacements.

Back to your lamp, is it possible the lamp is near the end of its useful life? Possibly electrode sputtering has blackened the inside of the gas envelope? Can you confirm actual power consumption? I don't know if higher cross-sectional currents in Hg vapor would change its spectral output...if not, you could probably compare this lamps' output against the equivalent of 175 watts of standard blacklight output. A friend of mine has 160W of 4' T12 blacklights (4 lamps total) in his apartment livingroom, it causes moderate fluorescence in cotton and fluorescent articles. Not very bright actually. The room is not that large either.


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## mattheww50 (Oct 30, 2003)

Mercury vapor lights do have high output in the UV spectrum, however there is very little mercury left in lighting these days. It has been regulated out of the lamps, just as it has been regulated out of batteries and other products. In a true Mercury vapor lamp, as long as their is mercury in the lamp, here will be UV output.

But there just about aren't any true Mercury vapor lamps any longer! They are lamps made that will operate in fixtures and with ballasts designed for mercury vapor, but they aren't mercury vapor.


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## JSWrightOC (Oct 30, 2003)

Interesting. So, why do they still call them "Mercury Vapor" and what is the fill gas nowadays?

How about fluorescent lamps? UV is still needed for the phosphor to convert to wide-spectrum visible light (well, wide-spectrum in the case of precision high-CRI lamps /ubbthreads/images/graemlins/tongue.gif).

I have noticed that most new outdoor installations (such as parking lots) involve either HPS (high-pressure Sodium) or Metal Halide lighting. That makes me happy, I hate the light output from mercury vapor lights...inefficient too.


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## PhotonWrangler (Oct 30, 2003)

[ QUOTE ]
*JSWrightOC said:*

Back to your lamp, is it possible the lamp is near the end of its useful life? Possibly electrode sputtering has blackened the inside of the gas envelope? Can you confirm actual power consumption? I don't know if higher cross-sectional currents in Hg vapor would change its spectral output...if not, you could probably compare this lamps' output against the equivalent of 175 watts of standard blacklight output. A friend of mine has 160W of 4' T12 blacklights (4 lamps total) in his apartment livingroom, it causes moderate fluorescence in cotton and fluorescent articles. Not very bright actually. The room is not that large either. 

[/ QUOTE ]

Thanks...

It's a 125w lamp; my mistake. But it was dim even when
it was brand new from the factory, and it only has about
2 running hours on it so far.

I've just fired it up again and lit up a 22w u-shaped
fluorescent blacklight (with integral BLB glass filter)
next to it and conducted some subjective brightness
tests using various things that fluoresced.

The vapor lamp was only a little bit brighter than the fluorescent, which was disappointing. I'm beginning
to wonder about that ballast, actually. I wonder if
they make electronic ballasts for these kinds of
discharge lamps - I think that would raise the
efficiency a little bit.

Thanks for the input.

but h


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## PhotonWrangler (Oct 30, 2003)

[ QUOTE ]
*mattheww50 said:*
Mercury vapor lights do have high output in the UV spectrum, however there is very little mercury left in lighting these days. It has been regulated out of the lamps, just as it has been regulated out of batteries and other products. In a true Mercury vapor lamp, as long as their is mercury in the lamp, here will be UV output.

But there just about aren't any true Mercury vapor lamps any longer! They are lamps made that will operate in fixtures and with ballasts designed for mercury vapor, but they aren't mercury vapor. 

[/ QUOTE ]

Hmm... it's listed as a mercury vapor lamp, and
it IS an older bulb, so it probably has more
mercury in it than more recent lamps. Here's
a catalog page that shows it - it's the smaller one - 

http://www.specialtyoptical.com/catalog/h125-bl_2712672.htm

Bought it from Philips back in the early 90s. Trying to
resurrect it for some Halloween effects. /ubbthreads/images/graemlins/wink.gif


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## PhotonWrangler (Oct 30, 2003)

[ QUOTE ]
*JSWrightOC said:*

How about fluorescent lamps? UV is still needed for the phosphor to convert to wide-spectrum visible light (well, wide-spectrum in the case of precision high-CRI lamps /ubbthreads/images/graemlins/tongue.gif).

I have noticed that most new outdoor installations (such as parking lots) involve either HPS (high-pressure Sodium) or Metal Halide lighting. That makes me happy, I hate the light output from mercury vapor lights...inefficient too. 

[/ QUOTE ]

Fluorescents still have mercury... just a lot less of it.
I think that xenon creates shortwave UV also, although
I'm not positive of this.

I also prefer the spectral quality of metal halide
lamps over MV lamps for outdoor lighting at night. Much
whiter, crisper and more natural looking.


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## PhotonWrangler (Oct 30, 2003)

Just noticed that you list yourself as a TV Engineer;
what do you do? We might have something in common. /ubbthreads/images/graemlins/grin.gif


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## JSWrightOC (Oct 31, 2003)

[ QUOTE ]
*PhotonWrangler said:*
Just noticed that you list yourself as a TV Engineer;
what do you do?

[/ QUOTE ]

TV Engineering, of course! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

I work for a TV station in Charlotte, NC...WBTV VHF channel 3. My title is Maintenence Engineer, but I do all sorts of stuff...working the evening shift you're a bit of a "one-man band"...

What do _*you*_ do? /ubbthreads/images/graemlins/tongue.gif


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## PhotonWrangler (Oct 31, 2003)

[ QUOTE ]
*JSWrightOC said:*
[ QUOTE ]
*PhotonWrangler said:*
Just noticed that you list yourself as a TV Engineer;
what do you do?

[/ QUOTE ]

TV Engineering, of course! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

I work for a TV station in Charlotte, NC...WBTV VHF channel 3. My title is Maintenence Engineer, but I do all sorts of stuff...working the evening shift you're a bit of a "one-man band"...

What do _*you*_ do? /ubbthreads/images/graemlins/tongue.gif 

[/ QUOTE ]

Video, fiber & network engineering in cable tv;
Network design, maintenance & consulting for
LED videowalls.

Electrons--->photons--->neurons. /ubbthreads/images/graemlins/grin.gif


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## JSWrightOC (Nov 1, 2003)

You make me jealous!

My dad works for Time Warner Cable in Charlotte. He's in the HDTV department. Although TW employees get free cable and Road Runner, sadly we do not live in the service area. /ubbthreads/images/graemlins/frown.gif We pay a mom-and-pop operation here out the toilet muscle for crappy looking cable and mediocre cable modem service. /ubbthreads/images/graemlins/rant.gif

Just this evening I was designing a GPI interface for a 360 Systems Instant Replay machine. This will be connected to our Kalypso production switcher so they can add sound effects to their transitions (but we're not going to be as overdone as Fox News! /ubbthreads/images/graemlins/grin.gif). In fact, I have been responsible for mixing and editing down the SFX so far...I love electronic design and working with audio. /ubbthreads/images/graemlins/smile.gif


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## PhotonWrangler (Nov 1, 2003)

[ QUOTE ]
*JSWrightOC said:*
Just this evening I was designing a GPI interface for a 360 Systems Instant Replay machine. This will be connected to our Kalypso production switcher so they can add sound effects to their transitions (but we're not going to be as overdone as Fox News! /ubbthreads/images/graemlins/grin.gif). In fact, I have been responsible for mixing and editing down the SFX so far...I love electronic design and working with audio. /ubbthreads/images/graemlins/smile.gif 

[/ QUOTE ]

Very cool! /ubbthreads/images/graemlins/cool.gif
I rememeber that the Video Toaster had some
transitions with built-in sound effects; nothing
terribly fancy, but the falling sheep immediately
comes to mind. /ubbthreads/images/graemlins/tongue.gif

HDTV, yeah, we're experimenting with this now.
Just brought home our first HD box, and I'm going
to be experimenting with the various spigots.
Also working with our training guys to get a
better grip on all of the different formats.
It's going to be an interesting learning curve!

NOW you've got me thinking about that 360 Systems
device... cut that out! /ubbthreads/images/graemlins/grin.gif


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## JSWrightOC (Nov 2, 2003)

Huh? /ubbthreads/images/graemlins/smile.gif

http://www.360systems.com

Thinking about what? /ubbthreads/images/graemlins/tongue.gif

http://www.360systems.com/docs/prod_ir_main.html

What did you say? Cut that out? Sure! /ubbthreads/images/graemlins/grin.gif


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## Lasernerd (Nov 2, 2003)

Check these out,,
this is what we use at our shows..

http://www.fogmachinesandhazers.com/bl400.html


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## PhotonWrangler (Nov 2, 2003)

[ QUOTE ]
*Lasernerd said:*
Check these out,,
this is what we use at our shows..

http://www.fogmachinesandhazers.com/bl400.html 

[/ QUOTE ]

Interesting... the site says that it's a metal halide
bulb? Is this a more efficient source of longwave UV
than mercury vapor?


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## PhotonWrangler (Nov 3, 2003)

[ QUOTE ]
*JSWrightOC said:*

http://www.360systems.com/docs/prod_ir_main.html

What did you say? Cut that out? Sure! /ubbthreads/images/graemlins/grin.gif 

[/ QUOTE ]

Thanks for the link... I think I've heard this system
(or something similar) on the air here and there and
I've always wondered what they looked like and who
makes them. Filing this away for future reference... /ubbthreads/images/graemlins/thumbsup.gif


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## JSWrightOC (Nov 4, 2003)

PM me if you're interested in the GPI project I'm working on. /ubbthreads/images/graemlins/smile.gif

Back on topic...

If Metal Halide lamps generate a lot of longwave UV, then how can they be so much more efficient than MV lamps? This means that every MH streetlight, parking lot light, indoor light, HID flashlight and headlight generates UV, and in many of thes applications it must be filtered out. Right? /ubbthreads/images/graemlins/confused.gif


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## PhotonWrangler (Nov 5, 2003)

[ QUOTE ]
*JSWrightOC said:*

If Metal Halide lamps generate a lot of longwave UV, then how can they be so much more efficient than MV lamps? This means that every MH streetlight, parking lot light, indoor light, HID flashlight and headlight generates UV, and in many of thes applications it must be filtered out. Right? /ubbthreads/images/graemlins/confused.gif 

[/ QUOTE ]

I think it only needs to be filtered out whenever it's
considered harmful or somehow pollutes the desired spectra.
HID headlights have that distinct bluish halo, which
I suspect is at least in part due to the presence of
longwave UV. In the case of headlights, I know that
bluish light tends to show more fog & haze, so maybe
any light at the blue end of the spectrum is harmful
in the presence of fog(?).

Back to blacklight usage though, I have no idea whether
the spectra from metal halide contains more useful longwave
UV energy than an equivalent wattage of MV lamp. I would
think, though, that since halides contain a lot more energy
towards the red end of the spectrum, this would produce more
heat buildup in the bulb since the visible wavelengths are
absorbed by the BLB filter glass.

Oh well, Halloween is over now, so I have another year
to worry about this. /ubbthreads/images/graemlins/tongue.gif

Thanks


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