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-   -   Red plants and LEDs (http://www.plantedtank.net/forums/showthread.php?t=227130)

wabisabi 01-27-2013 06:59 PM

Red plants and LEDs
 
Has anyone seen photos or been able to bring out vibrant deep reds in red plants using just led lighting? I thought I read somewhere that LEDs can't bring out the reds like T5s can.

Do you find this to be true? Please post a link or pic if you know of someone growing some vibrant deep red plants with LEDs.

Thanks!

Jeffww 01-27-2013 07:13 PM

My R. macrandra japan red is very read under 10k and blue LEDs...However you can't really see the redness unless you put them under a normal 6500k bulb. I think this is the issue. Most LEDs render reds very poorly.

Kensho 01-27-2013 07:28 PM

why would 6500 render differently depending on technology used?

TexasCichlid 01-27-2013 08:47 PM

It's not dependent on technology. It's dependent on a 10k visible spectrum vs a 6500k visible spectrum. If you had an LED system more towards 6500k color temp, you would see different colors come out than with a 10k.

Hoppy 01-28-2013 02:53 AM

LEDs and fluorescent lights don't produce spectrums that match certain color temperatures. Instead, LEDs tend to all have a big, wide peak in the blue area, and a much smaller peak in the red. Fluorescents have narrow peaks that are spread around, depending on exactly what phosphors are used. Because our eyes are relatively insensitive to red light, in order to see intense reds we need our lights to supply a big peak in the red area, making most of the LEDs we use somewhat deficient in that regards. But, if our goal is growing healthy plants, that look great in our aquascape, why do we need intense reds?

Tenor1 01-28-2013 03:31 AM

I have Ecoxotic 8000 Panorama's plus 2 magenta strips and my R macranda Japan looks nice and red. Even with the magenta strips off they look red.

csf 01-29-2013 03:59 PM

I think it's CRI - color rendering index. Natural light (sun) has lots of light in the various colors. CRI of natural light is 100. Surprisingly incandescent bulbs are also ~100 (probably since they are blackbody radiators, same as the sun). CRI isn't the same as light "color".

Artificial light isn't as well spread out. CRIs can drop into the 80s and lower. Really low for the old "fish tank bulbs".

You can still grow plants (good PAR), might still look good to the eye (color temp), but might be missing some of the spectrum.

A mix of bulb colors (LED or otherwise) is what lots of people do to help spread the spectrum out.

I've got a 50/50 of warm white and cool white 10W LEDs (8 of each). I'm toying with swapping some out for some blues and/or reds as it looks a little warm for my tastes.

The RGB LEDs look interesting too - red, green and blue in one unit. Needs it's own ballast however.

james1542 01-29-2013 04:24 PM

I'm not liking the CRI.

wabisabi 01-30-2013 07:42 AM

Quote:

Originally Posted by Jeffww (Post 2368658)
My R. macrandra japan red is very read under 10k and blue LEDs...However you can't really see the redness unless you put them under a normal 6500k bulb. I think this is the issue. Most LEDs render reds very poorly.

bummer!

Quote:

Originally Posted by Hoppy (Post 2373186)
LEDs and fluorescent lights don't produce spectrums that match certain color temperatures. Instead, LEDs tend to all have a big, wide peak in the blue area, and a much smaller peak in the red. Fluorescents have narrow peaks that are spread around, depending on exactly what phosphors are used. Because our eyes are relatively insensitive to red light, in order to see intense reds we need our lights to supply a big peak in the red area, making most of the LEDs we use somewhat deficient in that regards. But, if our goal is growing healthy plants, that look great in our aquascape, why do we need intense reds?

Yes, my goal is to grow healthy plants. But also to bring out all the beauty the plant has to offer as well. There's no denying that some red plants just have a certain 'WOW' factor. If you can grow healthy vibrant red plants, then why not have your cake and eat it too?

http://www.aquaticplantcentral.com/f...butterfly.html



Quote:

Originally Posted by Tenor1 (Post 2373538)
I have Ecoxotic 8000 Panorama's plus 2 magenta strips and my R macranda Japan looks nice and red. Even with the magenta strips off they look red.

Pics or it didn't happen!:tongue:

Quote:

Originally Posted by csf (Post 2386906)
I think it's CRI - color rendering index. Natural light (sun) has lots of light in the various colors. CRI of natural light is 100. Surprisingly incandescent bulbs are also ~100 (probably since they are blackbody radiators, same as the sun). CRI isn't the same as light "color".

Artificial light isn't as well spread out. CRIs can drop into the 80s and lower. Really low for the old "fish tank bulbs".

You can still grow plants (good PAR), might still look good to the eye (color temp), but might be missing some of the spectrum.

A mix of bulb colors (LED or otherwise) is what lots of people do to help spread the spectrum out.

I've got a 50/50 of warm white and cool white 10W LEDs (8 of each). I'm toying with swapping some out for some blues and/or reds as it looks a little warm for my tastes.

The RGB LEDs look interesting too - red, green and blue in one unit. Needs it's own ballast however.

Interesting..... I'm really looking for a commercially available premade fixture though. The thing stopping me from taking the plunge with LED's is that I haven't seen a tank running them growing nice red plants.

Steve001 01-30-2013 12:13 PM

Quote:

Originally Posted by wabisabi (Post 2395266)
bummer!



Yes, my goal is to grow healthy plants. But also to bring out all the beauty the plant has to offer as well. There's no denying that some red plants just have a certain 'WOW' factor. If you can grow healthy vibrant red plants, then why not have your cake and eat it too?





Interesting..... I'm really looking for a commercially available premade fixture though. The thing stopping me from taking the plunge with LED's is that I haven't seen a tank running them growing nice red plants.

Like the other poster said. You really need a mixture of different color leds. so that the CRI and kelvin temperature is very close to 100 and between 5500-5900k. It is doable by going the diy route. You can use the diy app at buildmyled.com. I played around with it and was able to create a light source with a CRI of 98 and Kelvin temperature of 5500-5900. I suspect that incorporating a yellow led it might bring that CRI to 100. There is a thread by a member using a fixture by that company. The thread contains photos of her planted tank.


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