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LED lamps UV light emissions?
Mar 21, 2016 16:27:45   #
pahtspix
 
There's been some discussion regarding the color temp of LED lamps. My current concern is UV emissions from LED lamps, do they or do they NOT emit UV?..We all know that MOST flourescents are big UV polluters, which will accelerate the fading of most COLOR prints on most papers..But how about "light from LED's"?..Need we be cautious regarding UV emissions from LED Light sources?
PAHTSPIX..(Eddie Wiseman)

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Mar 21, 2016 16:50:39   #
DirtFarmer Loc: Escaped from the NYC area, back to MA
 
pahtspix wrote:
There's been some discussion regarding the color temp of LED lamps. My current concern is UV emissions from LED lamps, do they or do they NOT emit UV?..We all know that MOST flourescents are big UV polluters, which will accelerate the fading of most COLOR prints on most papers..But how about "light from LED's"?..Need we be cautious regarding UV emissions from LED Light sources?
PAHTSPIX..(Eddie Wiseman)


I can't say I know in detail the spectrum of LEDs but I strongly suspect they do not emit any significant UV.

LEDs and fluorescent lamps are very different. The LED light comes from an electronic transition in an atom. That is a fixed energy, so it gives a fixed wavelength. There are many different atomic energy levels in an LED so you get a mixture of wavelengths, which make up white light. The first LEDs were red. Blue LEDs came much later. I believe the material used for the LED cuts off the energy levels pretty close to the blue.

Fluorescent lamps, on the other hand, start at the UV. Mercury is used because it has a strong UV line. The UV light hits the coating on the outside of the tube, which absorbs most of the UV light. The energy from the UV is then re-emitted at different wavelengths. The coating is made up of a mixture of materials (phosphors), each of which emits a fairly broad range of wavelengths compared to an atomic spectral line, but the range is generally a limited range in color. Different colors of fluorescent lamps are created by using different phosphor mixtures.

Since the fluorescent lamps require the UV light to get the phosphors to work, some of the UV leaks out. LEDs don't have that problem so they can be made to cut off closer to the blue.

Of course, blue light will also interact with the organic dyes used in color prints, just not as efficiently as UV light. Put your color prints in an album and limit their exposure to light in general.

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Mar 21, 2016 16:51:43   #
Violameister Loc: michigan
 
There is a lot of information on the web, including experimental evidence from incandescent, CFL and LED bulbs.

In short, unless the LED has been specifically manufactured to produce UV, for example for use in a greenhouse to illuminate plants, there is very little UV in the output of a standard LED bulb. It seems to be similar to an incandescent.

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Mar 21, 2016 19:52:32   #
Rongnongno Loc: FL
 
The only thing I can tell you is that my plants love the led light and discard the windows light for it...

Been growing herbs underneath and, well they grow like weeds.

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Mar 21, 2016 20:19:39   #
nicksr1125 Loc: Mesa, AZ
 
One of the selling points we use with LED bulbs in outdoor applications is that they do not emit UV light.

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Mar 22, 2016 05:46:17   #
Julian Loc: Sarasota, FL
 
Rongnongno wrote:
The only thing I can tell you is that my plants love the led light and discard the windows light for it...

Been growing herbs underneath and, well they grow like weeds.


Same here. 👍🏼👍🏼

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Mar 22, 2016 07:12:46   #
gmw12 Loc: Indianapolis & Windsor/UK & Montreux/Switzerl
 
http://www.leapfroglighting.com/lighting_and_uv_radiation/

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Mar 22, 2016 08:10:16   #
zigipha Loc: north nj
 
no uv.

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Mar 22, 2016 09:32:04   #
CHOLLY Loc: THE FLORIDA PANHANDLE!
 
DirtFarmer wrote:
I can't say I know in detail the spectrum of LEDs but I strongly suspect they do not emit any significant UV.

LEDs and fluorescent lamps are very different. The LED light comes from an electronic transition in an atom. That is a fixed energy, so it gives a fixed wavelength. There are many different atomic energy levels in an LED so you get a mixture of wavelengths, which make up white light. The first LEDs were red. Blue LEDs came much later. I believe the material used for the LED cuts off the energy levels pretty close to the blue.

Fluorescent lamps, on the other hand, start at the UV. Mercury is used because it has a strong UV line. The UV light hits the coating on the outside of the tube, which absorbs most of the UV light. The energy from the UV is then re-emitted at different wavelengths. The coating is made up of a mixture of materials (phosphors), each of which emits a fairly broad range of wavelengths compared to an atomic spectral line, but the range is generally a limited range in color. Different colors of fluorescent lamps are created by using different phosphor mixtures.

Since the fluorescent lamps require the UV light to get the phosphors to work, some of the UV leaks out. LEDs don't have that problem so they can be made to cut off closer to the blue.

Of course, blue light will also interact with the organic dyes used in color prints, just not as efficiently as UV light. Put your color prints in an album and limit their exposure to light in general.
I can't say I know in detail the spectrum of LEDs ... (show quote)


EXCELLENT!! :thumbup: :thumbup: :thumbup:

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Mar 22, 2016 10:38:40   #
lsimpkins Loc: SE Pennsylvania
 
DirtFarmer wrote:
I can't say I know in detail the spectrum of LEDs but I strongly suspect they do not emit any significant UV.

LEDs and fluorescent lamps are very different. The LED light comes from an electronic transition in an atom. That is a fixed energy, so it gives a fixed wavelength. There are many different atomic energy levels in an LED so you get a mixture of wavelengths, which make up white light. The first LEDs were red. Blue LEDs came much later. I believe the material used for the LED cuts off the energy levels pretty close to the blue.

Fluorescent lamps, on the other hand, start at the UV. Mercury is used because it has a strong UV line. The UV light hits the coating on the outside of the tube, which absorbs most of the UV light. The energy from the UV is then re-emitted at different wavelengths. The coating is made up of a mixture of materials (phosphors), each of which emits a fairly broad range of wavelengths compared to an atomic spectral line, but the range is generally a limited range in color. Different colors of fluorescent lamps are created by using different phosphor mixtures.

Since the fluorescent lamps require the UV light to get the phosphors to work, some of the UV leaks out. LEDs don't have that problem so they can be made to cut off closer to the blue.

Of course, blue light will also interact with the organic dyes used in color prints, just not as efficiently as UV light. Put your color prints in an album and limit their exposure to light in general.
I can't say I know in detail the spectrum of LEDs ... (show quote)

Excellent explanation of the light production process in both types of lamps.

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Mar 22, 2016 11:06:00   #
BebuLamar
 
LED initially are only red and infrared. Only later on that they can make them in the high spectrum and even in UV. So I think unless they want to they can make LED without UV easy.

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Mar 22, 2016 14:22:11   #
Brian in Whitby Loc: Whitby, Ontario, Canada
 
It is very unlikely that LEDs emit UV. If you are concerned, place a piece of 1/4 inch plate glass in front of it. Glass filters out Uv. Incidentally, halogen bulbs do emit UV and glass is used to filter it out.

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Mar 22, 2016 15:49:35   #
John_F Loc: Minneapolis, MN
 
Wikipedia has a quite good article on LEDs. Most use one or another of the 3,5 semiconductor p-n junctions with various dopants.

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Mar 22, 2016 21:09:24   #
pahtspix
 
I wish to thank all of you who Hoggers who chimed back on my question regarding UV pollution from LED's, and Im happy that the consenus is that there is no UV color fading due to UV light rays because Led's have very little or most likely none of those harmful side effects! I actually expected that resulr, but needed confirmation from those "in the know"..

THX again!

Eddie W
iseman (PAHTSPIX)

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