LUMENS, They don't add up?

I like Regret's analogy. A merge lane fits in well for that, both cars would be traveling the same speed as the two separate roads become one.

Can't see how lumens add, yes they illuminate more area when you add lights, but the actual brightness (intensity) doesn't increase, yet beneficial because the plant is receiving more light.

Yeah. I'm sorry, but I'm tired of seeing that lumens don't add when basic physics says they do. I'm also tired of being called stupid for saying so, when it's clear from both the results on this forum and some basic math that they do ... I think if there is a place for this discussion, it's in a thread with the phrase "lumens, they don't add up".

So, I apologize, but if you don't want to read it, don't.

firebullet said:

I like Regret's analogy. A merge lane fits in well for that, both cars would be traveling the same speed as the two separate roads become one.

Can't see how lumens add, yes they illuminate more area when you add lights, but the actual brightness (intensity) doesn't increase, yet beneficial because the plant is receiving more light.

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Do you know what intensity is?

well i say HID are Great for big grows as more light for the bill I Say CFL out push HID, out last HID and i can spray my leaves right before the lights go out and not worry about a bulb busting. oh and did i say that CFL don't cause to many heat issues and wait es come in single spectrum ,daul spectrum and mutli-spectrum setups that do in fact work for growing Cannabis and are Equally effective

just my $.02

ceestyles, I mean no offense here, but you have been putting down everyones answers (opinions) on this matter and have stated that they are wrong and have no proof, but I have yet to see you actually give any proof of your own, besides go look in a physics book. If you are so sure about what you are saying, why don't you enlighten us all. I would sure like some extra knowledge, if you've got it just lying around.

regrets said:

ceestyles, I mean no offense here, but you have been putting down everyones answers (opinions) on this matter and have stated that they are wrong and have no proof, but I have yet to see you actually give any proof of your own, besides go look in a physics book. If you are so sure about what you are saying, why don't you enlighten us all. I would sure like some extra knowledge, if you've got it just lying around.

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None taken. I'm not trying to put anyone down, but all I hear is opinion with nothing to back it up. Someone saying that two lights don't add intensity is simply wrong. Intuition or insistence doesn't make it any more right, and repeatedly stating fallacy as fact is just garbage and misleading to others.

Please see my posts on the thread below for all the science you could want, along with an experiment. I will summarize all this in a separate thread, but it will take a minute.

1550 watts of cfl s

ceestyle said:

Do you know what intensity is?

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Maybe I should ask you the same question?

Well if we've been referring to luminous intensity, it would be something like the amount of wavelength-weighted power in a direction from a light source, correct me if I'm wrong. Somewhat refered to as the model of the sensitivity of the human eye. Although the word 'brightness' was used, brightness is only perception and why I put intensity in parenthesis. so.. you sure you're asking the right person?

firebullet said:

Maybe I should ask you the same question?

Well if we've been referring to luminous intensity, it would be something like the amount of wavelength-weighted power in a direction from a light source, correct me if I'm wrong. Somewhat refered to as the model of the sensitivity of the human eye. Although the word 'brightness' was used, brightness is only perception and why I put intensity in parenthesis. so.. you sure you're asking the right person?

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Please read this: https://www.rollitup.org/indoor-growing/83128-lumens-lux-adding-all-up.html#post968899

If you have any more questions, please let me know.

i dont know if anyone has mentioned this but think of this.... plants outdoor receive aprox. 15,000 lumens per square foot... i saw this..

yojoe said:

Think about it as lumens per Sq.ft.

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.. and thought i would give you that fact as an idea of what goes on outside.... also a 150 watt HPS will be at about 15,000 lumens,,, so im not sure if that means you would have to have one 150 watt hps for every square foot of growing (next to impossible i would think) or not... does anyone have any comments on that?

p.s. how did this thread get so long?? the initial question is a VERY SIMPLE yes or no answer (YES, they don't add up) with a quite simple explanation... i didnt read the thread,, just thought i would ask.. unless all the people using 30 low watt cfls got involved.... LMAO

chuckbane said:

i dont know if anyone has mentioned this but think of this.... plants outdoor receive aprox. 15,000 lumens per square foot... i saw this.... and thought i would give you that fact as an idea of what goes on outside.... also a 150 watt HPS will be at about 15,000 lumens,,, so im not sure if that means you would have to have one 150 watt hps for every square foot of growing (next to impossible i would think) or not... does anyone have any comments on that?

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Yes. It's a bit more complicated. Outdoor sun is nominally 100,000 lux, which is 100,000 lumens per square meter, and approximately 10,000 lumens/square foot.

The 15000 lumens for a 150W HPS needs to be divided by an area that accounts for the distance from the bulb to the plant. With no reflector whatsoever, this would be 4 * pi * d^2, where d is the distance to the plant.

So say that you have your light 18" from your canopy with no reflector. You get :

15,000 lumens / (4 * pi * (18 inches * .0254 m / inch)^2) = 5700 lumens / m^2 = 5700 lux

If you move it down to 12", you bump up to nearly 13,000 lux. Add a reflector and some mylar and you can easily get even better.

When comparing, however, you have to remember that the sun is not out at full intensity for as long as your HID is on, and you haven't clouds to worry about.

yes but the clouds actually give the plants more sun a it traps the green house gases in. this i why you can get more sunburned on an overcast day than a sunny day. ask any surfer they know

ceestyle said:

...which is 100,000 lumens per square meter, and approximately 10,000 lumens/square foot.

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How in the fuck do you figure? 3.3 feet in a meter,, this means it would only be three times as much,, not 10 times,, dude how can i take your math seriously when you cant even convert metric properly?

Look I am a straight up noob when it comes to the main topic of this web site, I am on my first grow of 3 bag seed seedilings, which look great so far thanks to the help on here...I digress. I do know something about quantum physics, and in QP there is a phenonemon known as a cancelation pattern. It is what it sounds like, just look this up and it may shed some light on this subject. Seriously, no pun intended, just a high coincidence.

chuckbane said:

How in the fuck do you figure? 3.3 feet in a meter,, this means it would only be three times as much,, not 10 times,, dude how can i take your math seriously when you cant even convert metric properly?

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would you care to reread what you wrote before spouting off like you know what you're talking about? i'll give you a few minutes.

ok, i'm going to edit this, and for the reason that I too can snap like you did in the post above. Considering your other posts have been good-natured, I'll just point out that when converting area, the conversion factor is squared:

1 m^2 * ( 3.3 ft / m ) ^2 = 9.9 ft^2

There are about 10 square feet per square meter, and this is why there are about 10 lux per ftc.

BudLuvr said:

Look I am a straight up noob when it comes to the main topic of this web site, I am on my first grow of 3 bag seed seedilings, which look great so far thanks to the help on here...I digress. I do know something about quantum physics, and in QP there is a phenonemon known as a cancelation pattern. It is what it sounds like, just look this up and it may shed some light on this subject. Seriously, no pun intended, just a high coincidence.

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The conditions in this case are not those that require the inclusion of interference effects. An easy way to verify this is to put two lights next to each other, and notice that the light on the wall is consistent.

If interference were significant, you would see a pattern of light/dark stripes.

ceestyle said:

would you care to reread what you wrote before spouting off like you know what you're talking about? i'll give you a few minutes.

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dude you are a real arrogant prick... please tell me how 100,000 lumens/sqaure meter = 10,000 lumens/square foot

chuckbane said:

dude you are a real arrogant prick... please tell me how 100,000 lumens/sqaure meter = 10,000 lumens/square foot

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I'm arrogant? All you had to do is point out there was a math error if there was one (there wasn't). Instead, you drop the f-bomb and tell me I can't multiply! Seriously! Not to mention I edited it five seconds later. Check it.

In the same answer you will find the conversion from square feet to square meters.

chuckbane said:

How in the fuck do you figure? 3.3 feet in a meter,, this means it would only be three times as much,, not 10 times,, dude how can i take your math seriously when you cant even convert metric properly?

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3.3 X 3.3 is pretty close to 10

Koabear said:

yes but the clouds actually give the plants more sun a it traps the green house gases in. this i why you can get more sunburned on an overcast day than a sunny day. ask any surfer they know

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You can get burned, but you will not get more burned. Direct sunlight is stronger than the indirect light scattered by clouds.