7 replies to this topic

[gianteagle]

I've been thinking about making my own light... I've had a hard time finding any 415 nm LEDs.

It occurred to me that I could use an incandescent light with a gel color filter... I happen to have a small pin spotlight that I could use.

This manufacturer provides wavelength graphs for all of the hundreds of color filters they produce:

http://www.rosco.com/us/filters/supergel.asp

http://www.rosco.com/us/filters/roscolux.asp

http://www.rosco.com/us/filters/ecolour.asp

Several of the violet/indigo filters look like they would do the job.

And, if there's too much UV... the same supplier sells UV filters.

Any given filter retails for like $5-6 apiece.

Would this work?

[stevo396]

Just thinking about it quickly and looking at their site, i guess the first problem would be testing both the wavelength and intensity of the light coming through the filters.

I think it could work in theory. Though in my eyes its alot of work.

[stevo396]

im just reading on the roscolux product, they say in general it transmits 40% blue violet and 75% orange and red energy. So couldnt u get both red and blue light treatments in the one go, i.e 415nm and 620nm

Id write to the company and see wat they say. Ask it they think it would be safe to use on ur face tc.

[hhughes]

I think there would be a problem with this idea b/c you are not producing light.

You are only filtering out all other colors so that only 415nm would remain.

You can't create uV either by applying a gel.

basically... you are applying filtered light... instead of actual 415nm light...

so basically... you could sit under the light with no filter... and get the same amount of 415nm light that you would get if you just used a gel.

does that make any sense?

you need a light that actually produces 415nm only...

[stevo396]

i get wat ur saying, i think. Are u saying that the core function of a filter is to filter so it then wont let enough of the 415 wavelength through. Whereas led's would let 100% of the correct light onto the skin.

They got the ratings for most of the filters on how much light they let through, the highest ive seen is about 20% of the light getting through the filter.

[hhughes]

i get wat ur saying, i think. Are u saying that the core function of a filter is to filter so it then wont let enough of the 415 wavelength through. Whereas led's would let 100% of the correct light onto the skin.

They got the ratings for most of the filters on how much light they let through, the highest ive seen is about 20% of the light getting through the filter.

yeah in a way.

what im saying is.... applying the filter will ONLY let the wavelength or color of light through that you want.

for example... if you apply a blue gel/filter... it filters out all the other light... except the blue light.

BUT... it doesn't boost the strength of the light... if anything... it diminishes it. you might as well sit under the light with no filter.

you can't change light... you can only filter it or block it with a gel.

you need a 415nm "source" that is focused.

a gel doesn't focus... instead it just filters everything else out.

sort of like how green tinted glasses filter out yellow light to make everything appear brighter.

so i don't think using a filter would work.

you know how some people make their acne better by going out in the sun.... applying a filter would basically be like sitting under a giant translucent shade that only lets the 415nm wl through.

but with an incandecent... it will be infinitely less powerful.

[stevo396]

ahhh k yeh it would be as effective as sitting in the sun then...shame

[gianteagle]

It would be wasting energy as you're producing light at a bunch of wavelengths you don't need and then filtering it out, but it should still basically work. How much 415nm gets through depends on the power of the incandescent light, need more 415nm just get a stronger light. Right? Exactly what wattage you need I don't quite know how to figure out.

Or you could just stick a UV filter on a light and not care about all the rest of the visible light spectrum that you don't really need. It wouldn't be energy efficient but should still work?