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Quote: Lux clearly adds. No doubt about it... theres meters people have and you can buy for $25 to prove it. but Lumens cant add. Its physically impossible. Light moves in wavelengths at different speeds. Putting two lightbulbs of the same lumen, kelvin, watt does nothing to change the wavelength so your not getting any increase other then the light deminishes less over space. Just like a reflector helps do the same as putting another light there. It takes the photons shooting upwards (bulbs have 360 degrees of lighting) and points them downwards. Thus using the light that would normally be wasted and using it as a second bulb would act...
And here's where you're wrong.
Quote: Lumens don't measure photons. It's measuring perception and intensity, in relation to the human eye. It's not a matter of arguing the physics of light, it's matter of quantifying the way we can percieve it.
So you're trying to compare apples to oranges here. You're saying this isn't true because of the way photons work, but if lumens aren't measured by photon output then your argument is invalid. Since lumens are a measure of how we perceive light it is entirely plausible that they add up with more bulbs added. Are you going to tell me that a room is going to be as bright with one bulb as it is with 20? If I go in my veg cab right now and flip off one of my T-5 banks the grow area is visibly darker. If a lumen is a measure of light intensity, well, then my light just got less intense. If I flip it back on it becomes brighter, well, then my light just got more intense.
In the end we shouldn't be concerned with the energy released (which is what lumens measured) rather the illuminance which is how much light makes it to said object.
Quote: The problem is simply people assume taking 2 lights of the same lumens and putting them side by side you effectivly double your lumen output. And thats incorrect. Cause as soon as you go 1mm away from that bulb... you no longer have max lumen output (if you even had that at bulb ignition). The further to you; the less you get. When you put two bulbs together you simply decrease how much less you get as you step further away from the bulb.
Well that would hold true if for even one bulb. At the point closest to the source you would have a higher output then that of a point farther away. Adding in more bulbs doesn't make this any more or any less true. The lumen output would rise or fall according to distance (which is something that has already been pointed out).
Carotenoids, xanthophyll and chlorophyll are merely the pigments within the chloroplasts (photosynthetic organelles) that absorb the light. scientists have figured out down to the single nanometer exactly which wavelengths are absorbed best by each of these pigments. this is the "PAR" that kine referred to, PAR standing for Photosynthetically active radiation. The problem here is that although there are certain peaks where the pigments absorb best, they still do work at other wavelengths. just because they're best at one color doesn't mean that all the other colors are useless see this graph for an example.
Lumens are useless in this debate anyway since they in no way have any bearing on the activation of photosynthetic organelles. the only necessary measurement is the intensity of the light source.
Quote: Too make it more difficult, is it possible that marijuana has special photosynthetic organelles that other plants do NOT have because they are used by Cannabis spp. in the production of the psychoactive resin in the female flowers. I mean, the fact that a plant can make crystalline solids on its leaf surface, that when vaporized to the point of combustion, there are psychoactive in mammals (reptiles?). I mean, what other plant can such an unusual task.
You are absolutely correct, very good inference From the little research that's been done it's been speculated that UV-B is the specific wavelength for catalyzing production of THC but unfortunately until MJ gets classified in a schedule that allows medical research nothing concrete can be published
Just for everyone's reference on light wavelenghts, here's a diagram of the electromagnetic spectrum...
^ Note that the middle picture row has an unusual scale. Its for "Frequency", and the photos they put there are how "tall" the peaks of the wave are from eachother. Take the microwave lined up vertically with the photo for "Humans", is that a radiowave has a size of about a height of a human, head to foot (~5.5ft).
Also note how narrow the visible light spectrum is in comparison to the rest of the spectrum, its only a small fraction of the radio-to-gamma wavelenght range.
Hope that helps people with some of the confusion on the light spectrum. Hey Harry, can you calculate color temp, such as 2700 K using nanometers of a given light wave? It seems like they are directly related....
I think I like the term Irradiance for explaining electromagnetic radiation on a surface. This is the word I've been looking for to describe my scenario. I don't quite have all of the math to fully mathmatically explain multiple artificial light sources but I think is taking me in the right direction. Particularly when you look at the example of solar irradiation below. Where E adds in a linear fashion. Also this link helped a little. But right now I don't have the time to fully investigate this article. I.e. sit down with the math for a while.
What I'm having a little trouble with is whether or not the E from two identical CFLs is fairly equal. If I had to guess the answer is yes. Which I think means I= [(constant)/2][total E]^2. So the more lights the more E. If you have more E then you have more I. But like I said I have to sit down with the math from the above article to really sort out the E. Probably need some more information beyond that too. Maybe I can check the manufacturers websites and find E from a few CFL.
Irradiance From Wikipedia, the free encyclopedia Jump to: navigation, search Irradiance, radiant emittance, and radiant exitance are radiometry terms for the power per unit area of electromagnetic radiation at a surface. "Irradiance" is used when the electromagnetic radiation is incident on the surface. "Radiant exitance" or "radiant emittance" is used when the radiation is emerging from the surface. The SI units for all of these quantities are watts per square meter (W/m2), while the cgs units are ergs per square centimeter per second (erg·cm−2·s−1, often used in astronomy). These quantities are sometimes called intensity, but this usage leads to confusion with radiant intensity, which has different units.
All of these quantities characterize the total amount of radiation present, at all frequencies. It is also common to consider each frequency in the spectrum separately. When this is done for radiation incident on a surface, it is called spectral irradiance, and has SI units W/m3, or commonly W·m−2·nm−1.
If a point source radiates light uniformly in all directions and there is no absorption, then the irradiance drops off in proportion to the distance from the object squared, since the total power is constant and it is spread over an area that increases with the square of the distance from the source.
[edit] Technical details The irradiance of a light wave is given in terms of its electric field by , where E is the complex amplitude of the wave's electric field, n is the refractive index of the medium, c is the speed of light in vacuum, and ε0 is the vacuum permittivity.
Irradiance is also the time average of the component of the Poynting vector perpendicular to the surface.
[edit] Solar energy Irradiance due to solar radiation is also called insolation. The global irradiance on a horizontal surface on Earth consists of the direct irradiance Edir and diffuse irradiance Edif. On a tilted plane, there is another irradiance component: Eref, which is the component that is reflected from the ground. The average ground reflection is about 20% of the global irradiance. Hence, the irradiance Etilt on a tilted plane consists of three components: Etilt = Edir + Edif + Eref.[1]
The integral of solar irradiance over a time period is solar irradiation. Irradiation is measured in J/m2 and is represented by the symbol H.[1]
I found this under a wiki search on the word light. I found it informative about why one thing looks brighter than another. http://en.wikipedia.org/wiki/Light
Quote: Light is measured with two main alternative sets of units: radiometry consists of measurements of light power at all wavelengths, while photometry measures light with wavelength weighted with respect to a standardized model of human brightness perception. Photometry is useful, for example, to quantify illumination intended for human use. The SI units for both systems are summarized in the following tables.
[edit]
The photometry units are different from most systems of physical units in that they take into account how the human eye responds to light. The cone cells in the human eye are of three types which respond differently across the visible spectrum, and the cumulative response peaks at a wavelength of around 555 nm. Therefore, two sources of light which produce the same intensity (W/m2) of visible light do not necessarily appear equally bright. The photometry units are designed to take this into account, and therefore are a better representation of how "bright" a light appears to be than raw intensity. They relate to raw power by a quantity called luminous efficacy, and are used for purposes like determining how to best achieve sufficient illumination for various tasks in indoor and outdoor settings. The illumination measured by a photocell sensor does not necessarily correspond to what is perceived by the human eye, and without filters which may be costly, photocells and CCDs tend to respond to some infrared, ultraviolet or both.
As far as Gamma vs Visable light Wiki to the rescue.
Well, I'm back from the experiment and I've got some interesting results.
So, what I used for the experiment was two 27watt 5000K bulbs, 2 socket adapters, a 3 cell (each cell has a 1.5 volt MAX output) small solar panel, a digital multi-meter, a black shirt, some tape, and a completely dark room.
Here's most of the materials I used (black T-shirt and bulb adapters not pictured)....
First, I wanted to test the sensetivity of the panel and meter by covering the panel and leaving it open to the overhead incadencent bulb in the room. So, I taped the meter probes to the "+" and "-" terminals of just 1 of the cells, the center one. There is a total of 3 cells on this mini-solar panel. All readings on multi-meter are in 0.000 volts (about the range of a AA battery).
Middle solar cell Uncovered
Middle solar cell Covered
As you can see, the solar panel is very sensitive, even reading a small voltage even with my hand covering the cell.
Now, its time for the bulbs. Because it was difficult to hold the bulbs hovering at 1 inch above the solar cell, I descide just to rest the bulb on the surface of the cell. That way, it keeps it consistent as well.
The reading was 1.629 volts for one bulb.
Then I tried the 2 bulbs side-by-side to see what the difference would be....
The difference was slight, but still there was a difference. These bulbs produced a total of 1.629 volts on the solar cell, which is 0.1 volts more than the 1 bulb. Small difference, but still likely signifigant.
Lastly, for my own purpose, I did a "Y" arrangement (which is my current set-up for my own grow project) to see the effect of the 90 degree angle arrangement. The result were suprizing...
With a reading of only 1.076 volts on the meter, this is enough evidence for me to conclude that the 2-way splitter arrangement is very inefficient in its orientation.
The difference was dramatic. A full 0.563 volts in contrast to the side-by-side set-up which produced 1.639 volts. These results have made me reconsider my current "Y" spliter set-up. For the results of the 1st trial with the single bulb, I see that a horizontal orientation is best, so I will be building a custom lighting set-up that has multi-bulbs, side-by-side, in a horizontal plane in parallel arrangement because that appears to be the most efficient in terms of light production.
So, from this basic experiment, I will conclude that having multi-bulbs of the same lumens/wattage/Temp. color does not increase by a signifigant amount, but there is still an increase in the amount of available light (obvious logic really). I will also conclude that the "Y" orientaion of bulbs is very inefficent in comparison to side-by-side parallel arrangement.
If anyone wants to perform this experiment to test its validity, please do so and post the results to compare and see if you got similar results.
Quote: Plus, as i said before, this debate is entirely un-needed as plants dont care how many lumens.
my god you have an interesting interpretation of reality. I was under the impression that if the post had my name at the top then I was the one who said it. I'm sorry though, it must have been you because you're so incredible.
Quote: Kine said:
Quote: Harry_Ba11sach said: even amongst the scientific community theres a grand debate over photosynthesis and artificial lighting. In one camp they say that plants utilize the full spectrum from high frequency ultraviolet all the way down to far infra-red and that growing without the full broad-spectrum will yield deficient results. The other camp looks at graphs of peak photosynthetic efficiency and claims that since chlorophyll, xanthophyll and carotenoids all have their specific peak wavelength that putting energy into producing light at any other wavelength is just a waste of energy. I wish I had an answer for you, but professional biologists and botanists haven't even agreed on an answer yet.
Interesting. Hadent heard this... i had thought they came down to refining it to "Par" is the useable light... but then again; i dont know what "Par" consists of lol...
Quote: Harry_Ba11sach said: Carotenoids, xanthophyll and chlorophyll are merely the pigments within the chloroplasts (photosynthetic organelles) that absorb the light. scientists have figured out down to the single nanometer exactly which wavelengths are absorbed best by each of these pigments. this is the "PAR" that kine referred to, PAR standing for Photosynthetically active radiation. The problem here is that although there are certain peaks where the pigments absorb best, they still do work at other wavelengths. just because they're best at one color doesn't mean that all the other colors are useless see this graph for an example.
Lumens are useless in this debate anyway since they in no way have any bearing on the activation of photosynthetic organelles. the only necessary measurement is the intensity of the light source.
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see this graph for an example.
From the little research that's been done it's been speculated that UV-B is the specific wavelength for catalyzing production of THC but unfortunately until MJ gets classified in a schedule that allows medical research nothing concrete can be published 
