Best fluorescent blacklight tubes? And their data?

TCJ

Member
Even though I'm new here, and there was some UV light discussion in the past, I'm just going to dive in and post this... 'cause that's how I roll. (And past posts didn't answer my specific questions.)

So, what are your experiences re. fluorescent blacklights? And where can I get their technical data?

I've always hated the still-visible violet glow they emit, and wish a manufacturer could create an optical filter (either in/on the tube glass, or to cover the tube) that pretty much looks as black as the opaque paint on the metal fixture itself.

I tried F40T12BLB tubes from both Philips and G.E., and I found the Philips tubes had less purple spoiling the show compared to the G.E. But now I can't find any retailers here selling the Philips; they're all G.E. And even so, the Philips still wasn't as close to "perfect" as I'd like.

I tried looking up technical data on various UV fluorescent tubes (like emission spectrum graphs, phosphor chemistry, glass type (Wood's, quartz/silica, etc.), coatings on the tubes, etc.), but couldn't find anything. I also want to know more about their electrical properties, like filament resistance as a function of temperature, ideal filament temperature, gas breakdown voltage as a function of filament temperature, minimum sustainable arc current, maximum arc current without filament damage, etc. (The importance of this is evident in the next paragraph.)

High-pressure mercury vapour is not a solution for me, as I'm looking to build an instant-on/off, dimmable-down-to-zero UV lamp, that can be rapidly modulated across its brightness range (slew rate of 40W within 0.2s).
Of course I'm not 100% sure this is possible, but I believe it can be achieved... even if an instant "super dim" can only be achieved by firing a high-voltage arc across the tube in a carefully controlled high-frequency pulse-width modulation.

And I know all the rage is LED lighting now, but LEDs still suck for reaching small enough wavelengths, without spilling out a bunch of longer wavelength light and spoiling the desired UV fluorescence effect, and without destroying their own plastic/epoxy potting from the UV radiation, while still producing decently bright intensity, at a cost that's decently affordable.

So for this application, I think low-pressure mercury vapour fluorescent technology still reigns supreme.
...Anyone know just which ones have the least of that annoying purple glow? And where to find the technical data I seek?
 
What wavelength are you looking for? I know you said you aren't as interested in LED, but we do have an UV T8 LED Tube. It is 380-415nm. While I don't know how that compares with the mercury vapor tubes, people have been impressed with them. If you know that is too high, just ignore this. http://apollodesign.net/Products/View/4663.aspx
I'm also curious as to what your application is and if something different might work for you, but I'm guessing not, since you are asking about fluorescent tubes. However, I'll still mention that we have a UV LED fixture that is 365nm. There is no visible light from the fixture. It may be worth a look if you need a solution with better UV pop and no visible light spoiling the effect. Take a look. http://apollodesign.net/Products/View/4554.aspx
If interested in a demo unit or two of either item, contact an Apollo dealer, or if there isn't one near you, I'm sure @Kelite would love to help you out. Shoot him a message.
 
"No visible light" is what I desire... but I think a solution with that Avere 4UV is a little out-of-reach.

From what little technical data I could find on Philips BLB tubes, the efficiency was quoted at ~25%. So for a typical magnetically-ballasted 80W fixture (two F40T12 tubes), I don't think it's unreasonable to assume I'll get around 20W of actual light radiation, give or take a little. (The amount of true UV (<390nm) being slightly less.) Correct me if I'm wrong.

Looking at the Avere 4UV listed specs, max UV output is 5W. So I'd need 4 of them to replace every twin F40T12 fluorescent fixture, to get equivalent intensity. That brings up the price issue...

Reason I used a "typical magnetically-ballasted 80W fixture" in the example is, those can be purchased for $20 and painted black (on the outside) and a reflective metallized paint (on the inner surfaces). (The spraypaint cans themselves being only a few dollars, and lasting long enough to paint several fixtures.) And G.E. fluorescent F40T12BLB tubes can be had for about $15 ea. Compare that $50 (let's say) twin F40T12 UV light solution, with a quad Avere 4UV set costing $2800 (and that's with the 30% discount!), and you can see that's a lot of dollars just to get rid of the visible violet! (I'm just going by what I see on the product web page.)

Then we still have the dimming issue. Can the brightness of the Avere 4UV be controlled? Over how much range? How quickly? And can it dim-start? And what's the cold-start time?
My experience with simple dirt-cheap non-dimmable magnetic ballasts is the fluorescent tubes can cold-start within about 2~3 seconds, if the fixture is properly grounded. (Not good, but not bad either for applications that don't need the light to be modulated.) And I know commercially-available dimmable electronic ballasts for twin T12 and twin T8 fixtures can be readily purchased, with quoted dimming levels supposedly reaching down to approx. 20% of the tube's rated brightness. (I don't know if they can start the tube at a dim level, or how quickly the brightness can be modulated, or their typical price, but still.)

And even though designing an electronic ballast capable of wideband dimming, instant dim-start, and rapid slew rate / fast modulation is an electronics R&D challenge... possibly racking up the dollars too... I think the challenge could be somewhat fun. ;-) (And still less than $2800, all said and done.)
 
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I don't know what the output of Apollo's LED fixture is, but LEDs tend to be more efficient than other sources so it wouldn't surprise me if the output was similar or even better than what your getting from the fluorescent stuff. LEDs are also good at emitting very specific frequencies, so all of that 5w of light will be in the spectrum you want, and not wasted on the higher frequencies that you don't want. Unless there is some weird technology involved the LED's should be instant on, and able to strobe, dim, etc.
 
When it comes to UV, isn't it more about how well the UV reactive "subject" reacts to the light and not how many watts the unit is? It doesn't take as much to make something pop when you aren't battling the visible light. The visible light cuts down on the effect. In that respect, the 4UV fixture can beat the Altman 400W fixture.
 
Why not do a discharge fixture with a mechanical dimmer/dowser? I mean, they aren't cheap, but they really do a far better job than fluorescent.

Hmm... interesting idea.
4 things came to mind just now:

1. Can the dowser open and close at frequencies up to as fast as ~5 Hz?
2. Can the dowser's ballistics be reasonably managed? (ie. rapidly open-up or close-down to a specified position, without overshooting and oscillating too long?) I'm not a mechanical engineer, so this might be a little outside my realm. (Could be a fun project in terms of servos and tuning feedback loops, though.)
3. Can the dowser dissipate the heat? (Ok, the answer is "somehow yes", because cinema projectors have done this for almost a century. I guess the real question is "How?")
4. Being mechanical, would noise be an issue?

Perhaps the solution to these is to use a focused beam, put a small and fast servo-controlled mirror at the focal point, have a fixed matte-black "light absorber" to which the light can be deflected (similar to DLP projectors), and then optics to collect the "unwasted" light (that doesn't go to the absorber) and project it where desired?

Makes me wonder now, if there's already a commercial product (not necessarily UV) that works like this, and can be modified for UV... and rapid control...
 
Check out the high end Wildfire UV lights. I am pretty sure they have a bunch that are available with DMX controlled dowsers.
 
Hmm... interesting idea.
4 things came to mind just now:

1. Can the dowser open and close at frequencies up to as fast as ~5 Hz?
2. Can the dowser's ballistics be reasonably managed? (ie. rapidly open-up or close-down to a specified position, without overshooting and oscillating too long?) I'm not a mechanical engineer, so this might be a little outside my realm. (Could be a fun project in terms of servos and tuning feedback loops, though.)
3. Can the dowser dissipate the heat? (Ok, the answer is "somehow yes", because cinema projectors have done this for almost a century. I guess the real question is "How?")
4. Being mechanical, would noise be an issue?

Perhaps the solution to these is to use a focused beam, put a small and fast servo-controlled mirror at the focal point, have a fixed matte-black "light absorber" to which the light can be deflected (similar to DLP projectors), and then optics to collect the "unwasted" light (that doesn't go to the absorber) and project it where desired?

Makes me wonder now, if there's already a commercial product (not necessarily UV) that works like this, and can be modified for UV... and rapid control...

Wybron made one, there should still be some floating around, and other manufacturers may make them as well.
http://www.wybron.com/stage-lightin...ipse-IT-shutter/811020-2K-shutter-dowser.html
 
I spec'ed some Wildfires for an installation but that portion of the job was nixed so I never got to play with them. There's lots of data on the site. I believe they're 365nm which puts them out of visible range.
http://www.wildfirefx.com/products/lighting/
 
I wonder if you could find/build an LCD douser. Similar to what's used on auto-shade welding helmets.

This would be more fun if you'd describe what you're trying to accomplish on stage. I'm pretty curious about what you're doing with strobed blacklight.

Some background:
As a child, I was introduced to the classic "colour organ" or "light organ" party toy. I've always had a soft spot for these. (Though most have rather bad circuit designs, and really are just a novelty toy.) But what I do like about them is the dynamic changes in lighting is always synchronized to the music, and somewhat proportional to the music's characteristics.

One thing that's always left me dissatisfied with typical nightclubs and concert shows is the lighting has no link to the sound. At best, there's an operator / lighting technician on duty constantly changing programs and manually controlling the lights to what they think suits the music... but the synchronization and consistency isn't there. And many times I've witnessed the operator jumping to a program they thought would suit the next few beats, but the DJ suddenly changes to a different song, or the operator is unfamiliar with the song, and their prediction is wrong. If you watch the light patterns enough, and you're familiar with the songs, you can get a feel for what they're doing, and then you can see where they "goofed".
Then when you're working sound in the same booth where they're working lighting, and you see them suddenly jump to their console and hit a button 1+1/2 beats after the new phrase of the song began, you know they "goofed". ;-)

I've also seen (and used) lighting consoles that have the silly "TAP TEMPO" button on them... but that's kind of a crap-shoot band-aid solution to make lights seem synchronized to music... even though they're really not; The lights are running on their own asychronous clock which very soon drifts from the actual music tempo... especially when the music is performed by a live band that isn't using drum machines or synth rhythms or some kind of quartz-crystal regulated "tempo maintainer".

I've seen circuit designs on DJ mixers that attempt to automatically analyze the music and retrieve a beat reference, but these are usually just a simple audio low-pass filter (LPF), fixed comparator, and another beat-pulse LPF. No control over bandwidth or Q, no control of the second LPF's timebase, and when a song has a burst of rapid kick-drum pulses without the true tempo actually changing, the whole system breaks.

My intention is to create an effect where any fluorescent objects -- clothes, fashion accessories, painted sets, etc. -- things that people expect to glow, but not to have a modulated glow, will in fact flash and change intensity... synchronized with the sound... but actually following the rhythms of the sound, not some fixed steady tempo.

This requires an audio filter circuit that can be tuned to the precise aspects of the music you want the effect to track.
It also requires an "envelope filter" (LPF) that can be tuned to how "rapid" or "slow and relaxed" you want the effect to appear.
And the hard part -- it requires a dimmable blacklight that has a wide dimming range, with a very fast response.
 
Some background:
As a child, I was introduced to the classic "colour organ" or "light organ" party toy. I've always had a soft spot for these. (Though most have rather bad circuit designs, and really are just a novelty toy.) But what I do like about them is the dynamic changes in lighting is always synchronized to the music, and somewhat proportional to the music's characteristics.

One thing that's always left me dissatisfied with typical nightclubs and concert shows is the lighting has no link to the sound. At best, there's an operator / lighting technician on duty constantly changing programs and manually controlling the lights to what they think suits the music... but the synchronization and consistency isn't there. And many times I've witnessed the operator jumping to a program they thought would suit the next few beats, but the DJ suddenly changes to a different song, or the operator is unfamiliar with the song, and their prediction is wrong. If you watch the light patterns enough, and you're familiar with the songs, you can get a feel for what they're doing, and then you can see where they "goofed".
Then when you're working sound in the same booth where they're working lighting, and you see them suddenly jump to their console and hit a button 1+1/2 beats after the new phrase of the song began, you know they "goofed". ;-)

I've also seen (and used) lighting consoles that have the silly "TAP TEMPO" button on them... but that's kind of a crap-shoot band-aid solution to make lights seem synchronized to music... even though they're really not; The lights are running on their own asychronous clock which very soon drifts from the actual music tempo... especially when the music is performed by a live band that isn't using drum machines or synth rhythms or some kind of quartz-crystal regulated "tempo maintainer".

I've seen circuit designs on DJ mixers that attempt to automatically analyze the music and retrieve a beat reference, but these are usually just a simple audio low-pass filter (LPF), fixed comparator, and another beat-pulse LPF. No control over bandwidth or Q, no control of the second LPF's timebase, and when a song has a burst of rapid kick-drum pulses without the true tempo actually changing, the whole system breaks.

My intention is to create an effect where any fluorescent objects -- clothes, fashion accessories, painted sets, etc. -- things that people expect to glow, but not to have a modulated glow, will in fact flash and change intensity... synchronized with the sound... but actually following the rhythms of the sound, not some fixed steady tempo.

This requires an audio filter circuit that can be tuned to the precise aspects of the music you want the effect to track.
It also requires an "envelope filter" (LPF) that can be tuned to how "rapid" or "slow and relaxed" you want the effect to appear.
And the hard part -- it requires a dimmable blacklight that has a wide dimming range, with a very fast response.

I don't think you understand how lighting programming works. It can be sequenced to a specific show and many large production, large budget shows are done that way. Just watch anything by Nine Inch Nails.
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Many times because of budgetary constraints, the artist doesn't carry an LD (Lighting Director) and the house or lighting supplier furnishes the LD. He doesn't know the show, and many times maybe not even the music. He has to "Punt" or "Busk" the show, which is on-the-fly operating of the console. Even when the artist carry's an LD, many times they don't carry a console or lights. He has to learn the console, and run different fixtures every night. I just don't think you realize what goes into programming a show. Here is a video that will explain the concept of "busking".
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I think the OP is talking about night clubs, or small venue concerts that may be busked, or even just have a DJ or sound guy firing sequences. He's looking for a way to automate lighting effects that respond to the music. Sounds cool to me.
 
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Most lighting consoles have an audio input for that exact reason.
 
I don't think you understand how lighting programming works. It can be sequenced to a specific show and many large production...

Of course the lights can be sequenced for a specific show... but that's exactly the problem -- everything is pre-programmed! The lighting console steps through the programs at a speed determined either by its internal clock, or the operator pressing a button. Never the actual audio signal itself!

In live band settings, if the musicians' tempo drifts (which it does), the lights do not automatically follow. (Think sequence steps that need to advance precisely in time with the beat.) I've only seen such "pseudo-sync" implemented by a lighting technician manually tapping a button on the console in sync with what they hear.

And in nightclub / dance hall / wedding / party scenarios, where the DJ is constantly "reading the crowd" and choosing the music selections accordingly on-the-fly, there is no scripted / pre-planned sequence for the whole show, obviously. You have a lighting technician who programmed a bunch of preset "moods" and "effects" (who could be the same person as the DJ, for a small event like a wedding), then manually chooses the preset they feel is appropriate for the song that's playing.

The night before a reasonably-large dance party event I was working (~500 people, rotating through 900 ticket sales), lighting tech was still programming his lights well into the wee hours of the morning, long after we had PA assembled. He was using a laptop computer running Lumidesk and a USB-DMX512 interface. And everything was just a set of sequences he could "call up" and execute at any arbitrary speed, completely independent and isolated from music. There was not even 1 wire linking his lighting control computer to the sound system. Nothing about the lighting show was automatically proportional or automatically representative of the sound in any way. He had various strobe sequences, slow sweeps as well as fast twisting and whirling sequences for his Varilites, colour presets, gobo presets... but it was all presets!

When it was showtime, he (or his friend) sat at the computer, and just clicked which program sequence to execute based on the mood of the music they were hearing from the DJ. Strobes were not in sync with the beat. The amount of light intensity variation was not based on the dynamic range of the music; it was based on what button the technician clicked on his Lumidesk interface.

In contrast, a good "colour organ" / "light organ" automates this, and keeps it in sync. For a live band: A feed from the drummer's kick drum mic driving a colour organ will always flash that light precisely on-point with when he kicks his drum, no matter when or how fast. Another colour organ on his crash cymbals mics will trigger some other light cluster every time he slams them on a fill, no matter when it occurs. A colour organ on the lead vocal's mic will light up on every word they sing, at the precise moment they sing them. Including any impromptu phrases that weren't pre-planned or called on a stage manager's cue. A (good) colour organ on a DJ's performance will always vary the light intensities more for songs that have wide dynamic range (think James Brown and similar R&B where the lead vocal's "punch" is far louder than the backing instruments"), compared to songs that are fairly consistent like ambient lounge. A (good) colour organ driving RGB lights will vary the resulting lighting hue in proportion to the DJ playing around with his tone filters, exactly in sync with the DJ's filter sweeps.

No lighting technician "punting" or "busking" at their console, or stage manager calling cues for a big production, can match the perfect timing accuracy of complex light pulses, proportional to the music, that makes the colour organ / light organ effect impressive.

So back to the original topic... I'd like to bring this effect to ultraviolet lights too, so clothing and fashion accessories and props can "glow" with similar pulsations and modulations.
 
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Of course the lights can be sequenced for a specific show... but that's exactly the problem -- everything is pre-programmed! The lighting console steps through the programs at a speed determined either by its internal clock, or the operator pressing a button. Never the actual audio signal itself!

In live band settings, if the musicians' tempo drifts (which it does), the lights do not automatically follow. (Think sequence steps that need to advance precisely in time with the beat.) I've only seen such "pseudo-sync" implemented by a lighting technician manually tapping a button on the console in sync with what they hear.

And in nightclub / dance hall / wedding / party scenarios, where the DJ is constantly "reading the crowd" and choosing the music selections accordingly on-the-fly, there is no scripted / pre-planned sequence for the whole show, obviously. You have a lighting technician who programmed a bunch of preset "moods" and "effects" (who could be the same person as the DJ, for a small event like a wedding), then manually chooses the preset they feel is appropriate for the song that's playing.
A Grand MA2 can use audio inputs as the actual trigger for each or any cue. If fact there are many options. A manual GO, Time, Follow, Sound, BPM (beats per minute), SMPTE and MTC (midi time code) are all options.

In live band settings, a drummer will wear a headset with a click track to keep the band in time with the programming. Have you ever seen an artist play a song live to their music video? That's exactly how they do it. Not only are the lights sequenced, but the ProTools rig, keyboards, vocal tracks, etc.

Many LD's write a song per page and when the song changes, they just turn the page for that specific song. So the artist (or DJ) can change the set to match the audience. Each page will normally have a main sequence (cue list) and additional faders and executors for ad-libbing or adding accents like audience blinders, ACL's. That gives him the best of both worlds, to be able to follow a scipted song, and punt at the same time.

As for black lights, especially the florescent type, there is not really a good instant on because the lamps need to come to full temperature before they reach full output. There are LED's in the 380mn range that can be turned on instantaneously. But they're visible to the eye. 365mn is invisible.
 

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