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We use red light for high speed videography. currently we use a Tungsten light source with a Red filter. Unfortunately, the Tungsten light source creates too much heat for our laboratory use.

We want to find an alternative light source for our videography and have been trying to work with LED lighting. We are currently trying to work with a white LED light source, the spectrum of which looks as follows ---

White LED Spectrum

I want to filter out red light from this white LED source. But as you can see the spectrum dwindles in the red zone.

And therefore, when I put red filter (absorptive filter) in front of my white LED light source, the brightness suddenly drops down to abysmal values.

Is there a way in which I could use this spectrum and get red lights without compromising on the brightness? I thought about interference and then I came across dichroic filters. But I'm not sure if that'll do it.

I also came across these filters called LEE LED filters which are filters specifically meant for LEDs. From the spectrum shown in the link, these filters can give you more than 85% red. But the overall transmission is just 10.1% of the original intensity. So it's kinda bleh. Or maybe I don't understand properly. I would be grateful if you can follow the link and explain to me , if I am wrong.

A red LED light source would be just perfect for me, but a high wattage (50W-100W) red LED light source is hard to come across in the market. Do you guys have any suggestion ?

Let me know if there are other options you guys can think of, for producing cool red LED light. Right now I use a tungsten lamp with RED absorptive filter, but there is so much heat (infrared) in it that my houseflies get fried up. [ I work in an insect flight lab and we use red light for high speed videography, since houseflies dont see well in the red zone]. So I want to switch to LEDs.

  • Can't you convert it to black&white, and then drop the blue and green channels? Or am I thinking too simplistic? – Jeroen Kransen Jul 31 '14 at 13:05
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    This question appears to be off-topic because it is about LEDs and light filtration not in a photographic context. – Matt Grum Jul 31 '14 at 13:08
  • Electrical Engineering SE might be able to suggest an alternative light source comprised of red LED's? – James Snell Jul 31 '14 at 19:36
  • @BShaw - Videography is still off topic to this site. – John Cavan Aug 1 '14 at 12:31
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    This might be a good choice for the Physics SE. We have a lab here that has a fruit fly tracking project, according to ftp.aip.org/epaps/phys_rev_lett/E-PRLTAO-104-146101/… they use these high power LEDs: digikey.com/Web%20Export/Supplier%20Content/Osram_475/PDF/… although I don't know what color. Why do you need red? – ARM Aug 1 '14 at 17:47