UV effect with LED

[Ian Cunningham]

Good Evening

 

I'm working on a panto LX design that needs a UV scene (not purely UV, but using UV to activate UV sensitve costumes on the "bugs" for Ugly Bug Ball)

 

I would normally use a couple of 400W UV cannon but was wondering if an LED solution may be better (the warm up time of the discharge lamps is an issue)

 

Not having used UV LED before I'm uncertain of how much power I need to match a 400w discharge or how effective UV LED is at all

 

IF anyone has used LED Uv before I'd be interested in your experiences and any recomendations for equipment

 

cheers

 

Ian

[mac.calder]

Your problem is wavelength.

 

LED's are typically fairly narrow in the wavelengths of light they put out. UV reactive items are generally fairly specific in the wavelengths they fluoresce at - and they are not all at the same wavelength. Your wildfires and UV cannons will traditionally be fairly broad-spectrum UV - spiking between 350 and 400nm. Most UV panels I have seen are around the 400-410nm range which is bordering on the visible spectrum.

 

Best solution is wildfires with DMX controlled shutters IMO.

 

Alternatively I believe wildfire have an LED fixture which is 365nm which is around the sweet spot for most things that fluoresce.

[timsabre]

Another problem is cost, you will need to spend a lot to get uv led of equivalent brightness to a 400w uv cannon.

 

Although Mac is right about wavelength if you need proper uv, fluorescent items will actually glow brightly under blue Led. So if you're not looking for a true blacklight but just want to make the fluorescent colours "pop" then led pars set to Blue might do it for you.

[garysmith]

Don't know if you have anything like this available but these are great. http://www.altmanltg.com/altman-featured-project-liberty-university.htm

[paulears]

Led blue will make uv fabric and paint fluoresce over the top of the blue visible light. Did a dance show week before last where the effect was really vivid, and unexpected. The trouble with the Specific LED UV types is they are still putting out light you can see, so the traditional uv scene where you cannot see the black clad operators doesn't work that well, as they are still visible! Led uv sources are brighter and more controllable than uv cannons, but as said above, the frequency of the LED light makes them behave differently.

[Guest]

After hiring some RGBAWUV LED PARs, I will never go back to UV cannons. I used some Visage Multipars I believe and they have a UV wavelength of around 400nm, which is visible, but still very effective. They're bright too, and with a very wide beam angle and so I used 4 pairs as pipe-ends. And at the end of the day they're not discharge, and so the ease of control is fantastic.

 

Edward

[musht]

 

Alternatively I believe wildfire have an LED fixture which is 365nm which is around the sweet spot for most things that fluoresce.

 

As well as Widlfire, Altman as mentioned , Rosco and Apollo all make 365nM units, sit down when you look at the price though. Low wavelength LEDs are expensive.

 

Human visibility of light drops a steep slope below 400nM , 365nM is trues blacklight can only see items glowing as they re-emit light at a higher visible wavelength.

 

If its not important for true blacklight, 400nM and above will still make things pop. Visible light fluoresecence,so not to be confused with the type of UV filtering Wood`s glass the effect should be called the `Frank Effect` ;-)

 

 

Bit too old to include LEDS but still some good coverage of the subject:

 

http://donklipstein.com/uvbulb.html

[Bryson]

I had a play with the Rosco Miro Cube UV the other day. They're amazingly bright. We were saying how bright it was and then noticed we only had it on at 50%. It's punchy.