^^^^ Stacking Lumens ****

rivers2gates

rivers2gates

Well-Known Member
Happy easter everybody!
I have a question, i have seen it debated a couple times but for the life of me i cant find any threads on the topic.

I have noticed recently people advertising that they have for lack of a better example 2x42 watt cfl's. some users assume that since they are getting 2500 lumens out of each bulb that their grow room should hold 5000 lumens.

I have always been under the impression that lumens could not be "stacked". However, 31 flashlights shining on a spot on a wall will be far brighter that 1 flashlight....so i dont know

Can anyone help clear this up?:joint:
 
JohnnyBravo

JohnnyBravo

Well-Known Member
31 flashlights shining on a spot on a wall will be far brighter that 1 flashlight.....I think you just answered your question!!!!
 
JohnnyBravo

JohnnyBravo

Well-Known Member
Tanuvan said:
I answered it here

https://www.rollitup.org/cfl-growing/57813-advantage-v-disadvantage-cfl-s-8.html#post660595

You can stack lumens, but you can't increase intensity by adding more light. I posted the formulas and everything.
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I'm not good with math and formulas.....explain this if you can....I use 6 t5 flouros to veg with....when I turn off a couple of them the light gets dimmer....Like comparing evening light to 12 noon light.....brighter equals more intense...Doesn't it?????
 
Tanuvan

Tanuvan

Well-Known Member
No, brighter equals more perceived light to the human eye. Or more lumens. Intense light can be bright...but it does not have to be. Consider some lasers. They can be very intense, but not very bright in our visible spectrum.


The key word is perceived. If you have an extremely bright green light, and a dull blue light, the blue light will appear brighter to a plant because it can't see green. So the green light while more lumens to a human, will actually be less lumens to a plant.

So in short, intense light CAN be bright, but bright light does not necessarily mean it will be more intense. Bright light...to a human eye will always have more lumens or lux...the more light...the more perceived brightness...the more lumens.
 
JohnnyBravo

JohnnyBravo

Well-Known Member
Tanuvan said:
No, brighter equals more perceived light to the human eye. Or more lumens. Intense light can be bright...but it does not have to be. Consider some lasers. They can be very intense, but not very bright in our visible spectrum.


The key word is perceived. If you have an extremely bright green light, and a dull blue light, the blue light will appear brighter to a plant because it can't see green. So the green light while more lumens to a human, will actually be less lumens to a plant.
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I call BS.......my lights are 6500k spectrum(BLUE LIGHT)....If I perceive more green light it would stand to reason there is more green light....Just because I don't perceive more blue light doesnt mean there isn't more blue light...Its just not reflected off the green leaves....you imply that adding more lights only increased the green light...in doing that you concede that adding lights increases the amount of light....if it increase the green light, it has to increase the entire light spectrum that the bulb produces.....hence why it is brighter when i add more lights....:)
 
Tanuvan

Tanuvan

Well-Known Member
LMAO you call BS, and you want me to exclude the math that proves it?

That was called an analogy. Wow, when you try to simplify something...people want to point out the technicalities...when you are too technical, they want you to simplify. Which is it do you want?

If you perceive more green light, it doesn't mean that technically there is more green light present. It just means that the pigment in your eye is sensitive to that spectrum. Yes, of course the entire spectrum increases...but in all practicality for this example it does not matter because the human eye cannot see outside of the visible spectrum.

I won't argue something that is already been proven scientifically. In the vein of keeping things simple, if you add more light...generally the lumens increase, but not the intensity.
 
C

cyks

Well-Known Member
You guys should be careful about word choice before seriously arguing. Although Tanuvan is more correct, "Intensity" is a pretty vague word. #2 Plants can't see; they don't have eyes... so be careful there too lol. From wiki, "Light with the same radiant intensity at other wavelengths has a lower luminous intensity, but radiant intensity is distinct from intensity defined by irradiance or radiant exitance which measure radiation directed at or emitted from a given surface area." This is all relative to the human eye.

In other words, adding more lights will help increase the photosynthetic response, but if they are more CFLs, the photosysthesis doesn't work any more efficiently than if the lights were HPS. You cannot make sunlight from a million CFLs! Not 2 million, not ever!
 
JohnnyBravo

JohnnyBravo

Well-Known Member
Tanuvan said:
LMAO you call BS, and you want me to exclude the math that proves it?

That was called an analogy. Wow, when you try to simplify something...people want to point out the technicalities...when you are too technical, they want you to simplify. Which is it do you want?

If you perceive more green light, it doesn't mean that technically there is more green light present. It just means that the pigment in your eye is sensitive to that spectrum. Yes, of course the entire spectrum increases...but in all practicality for this example it does not matter because the human eye cannot see outside of the visible spectrum.

I won't argue something that is already been proven scientifically. In the vein of keeping things simple, if you add more light...generally the lumens increase, but not the intensity.
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Ok there buddy, answer this....The reason the light seems brighter is because of my sensitivity to green light....If I add more light, it seems brighter to my eye because the intensity has increased....Booo Yaaaa...Buddy....In your Face!!!!
 
Roullette

Roullette

Well-Known Member
lumen= 1 square foot candle of light..

its pretty obvious. if you have one bulb that has 10 lumens its gonna light that area 10 foot candles in a square foot.. you would have to take the 2nd bulb and move it to another location for it to cover another area. its not gonna light further its just gonna over lap that same area.because there putting 10 lumens of light on the same area. .. you would have to move the bulbs to get better coverage.

your comparing with flash lights that have built in reflectors.. now if you add a reflector thats a different story.
 
Tanuvan

Tanuvan

Well-Known Member
I am not even going to entertain you Johnny...yeah..you got me...all in my face. I couldn't pull one over on you!

CYKS, again I was simplifying. If you want the actual calculations, I've listed them elsewhere. I think it is pretty clear that plants can't "see" light because they have no eyes. It was an analogy. An attempt to explain something more complicated in simple terms.

Apparently, I can't do that on this site. So from now on, I will be technical. By "seeing", I was referring to the wavelengths that correspond to plant chlorophyll A & B.

So what appears bright to our eyes lumen wise or intensity may have no impact to a plant if it is not within the plants usable spectrum.
 
Tanuvan

Tanuvan

Well-Known Member
Roullette said:
lumen= 1 square foot candle of light..

its pretty obvious. if you have one bulb that has 10 lumens its gonna light that area 10 foot candles in a square foot.. you would have to take the 2nd bulb and move it to another location for it to cover another area. its not gonna light further its just gonna over lap that same area.because there putting 10 lumens of light on the same area. .. you would have to move the bulbs to get better coverage.

your comparing with flash lights that have built in reflectors.. now if you add a reflector thats a different story.
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What you are increasing by adding more lights is lumens. Intensity is altogether different and it has to do with the amount of energy a photon is carrying. When you calculate intensity, it becomes complicated because the functions depend on whether the packets are being emited from a point source. That is why LED's are different than a light bulb insofar as the math is concerned.
 
Tanuvan

Tanuvan

Well-Known Member
cyks said:
You guys should be careful about word choice before seriously arguing. Although Tanuvan is more correct, "Intensity" is a pretty vague word. #2 Plants can't see; they don't have eyes... so be careful there too lol. From wiki, "Light with the same radiant intensity at other wavelengths has a lower luminous intensity, but radiant intensity is distinct from intensity defined by irradiance or radiant exitance which measure radiation directed at or emitted from a given surface area." This is all relative to the human eye.

In other words, adding more lights will help increase the photosynthetic response, but if they are more CFLs, the photosysthesis doesn't work any more efficiently than if the lights were HPS. You cannot make sunlight from a million CFLs! Not 2 million, not ever!
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I am not sure what you are getting at. Are you prepared to explain the effects of different light intensities (in your case you mentioned CFL and HPS) with regards to the photosynthetic response? If so, I would be glad to see this. Please post your math so that I can calculate it myself.

I am interested in your statement on the efficiency you alluded to in your aforementioned paragraph. It would seem that you are referencing blackman's law, but I've yet to see anyone here or elsewhere put up the calculations for a plant's light saturation point.

Thanks
 
JohnnyBravo

JohnnyBravo

Well-Known Member
I don't know all your math but, If I had a meter that only reads blue light and I turned on one of my T5's.....the more of my lights I turn on the higher the meter would read....you know it....I know it....so again...BOOOOOOO YAAAAAAAA.....LMAO:)
 
Tanuvan

Tanuvan

Well-Known Member
JohnnyBravo said:
I don't know all your math but, If I had a meter that only reads blue light and I turned on one of my T5's.....the more of my lights I turn on the higher the meter would read....you know it....I know it....so again...BOOOOOOO YAAAAAAAA.....LMAO:)
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You are the MAN!!!! :hump:


" this forum isnt about spectrum output its lumens" <- All of it is important if we are to maximize efficiency. You have to have the correct spectral output, maximum "usable" lumens, and enough intensity.

It's all good though. I am done with this topic. :joint:
 
formypleasure

formypleasure

Member
This is old topic and i need to say something about it for all who will read it in future so that they dont get confused in this arrgue.

"To be honest every1 said something smart here but TANUVAN got the point about spectrum and intesity. Its clearly that the man know something about light and not just speculates."

Nice posts Tanuvan.
 
dluck

dluck

Well-Known Member
Does this have something to do with the cri ratings on bulbs...my CFL's are rated at 80 cri's
 
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