LED Brightness

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ClassAcura

Active Member
Does the brightness of the LED light matter? I have 2 LED lights, a 357 Mag+, and a 600w Blackstar. When turned on, the Blackstar is significantly brighter than the Mag+. I was under the assumption the Mag+ is the more powerful light, but the Blackstar is much brighter. Does brightness matter with LEDs?
 
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PurpleBuz

Well-Known Member
ClassAcura said:
Does the brightness of the LED light matter? I have 2 LED lights, a 357 Mag+, and a 600w Blackstar. When turned on, the Blackstar is significantly brighter than the Mag+. I was under the assumption the Mag+ is the more powerful light, but the Blackstar is much brighter. Does brightness matter with LEDs?
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preceived brightness by the human eye can be misleading since we our sensitive peak is green light (~550nm). Some LEDs throw in some white or greens that make it brighter, and others have more red\blues which won't appear as bright. The plants have absorption peaks in both the blue and red ranges, and less in the green.
 
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ClassAcura

Active Member
The Blackstar has about 90% Red LEDs and 10% Blue. The Mag+ Has about 70% Red, 20% Blue, 7% White, and 3% Infrared LEDs. Based on the article, I am assuming that the perceived brightness of the human eye is greater on the 600w Blackstar than on the 357 Mag+, even though the Mag+ is the more powerful light here.

Is my understanding correct?

This LED stuff is too complex for me!!!!
 
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SnotBoogie

Well-Known Member
Sounds like you understand, to me :) Though i dont know the ins and outs of those panels, i would assume they are putting out light that is relatively closer or further from the peak of human eye's sensitivity (555nm) - i.e the reds on the blackstar might be mostly 630nm (closer to the peak of human sensitivity) while the reds on the mag+ might be 660nm (further away from the peak) making the BS look brighter. This is just a guess to illustrate to you, though.
 
tags420

tags420

Well-Known Member
To know the unbiased intensity of the light you want to know the par output in umols. PAR readings are unweighted, meaning each photon is valued the same no mater the wavelength.
Then there is the absorption rate curve within PAR light that the plants go by, which is where we see the red and blue peaks that led's target.
 
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ClassAcura

Active Member
In my case, would a meter determine which light is actually more powerful? Even though the Blackstar is much brighter?
 
tags420

tags420

Well-Known Member
ClassAcura said:
In my case, would a meter determine which light is actually more powerful? Even though the Blackstar is much brighter?
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Yes. It would tell you how many photos are falling in a m^2/sec equally regardless of the wavelength each photon. This will show you which is actually putting out the most light.
If the par readings were exactly the same...the differences in spectrums would have the final effect based on how well they follow the absorption rate curve.
 
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