Light Penetration?

[Hackerman]

Another variable for the equation that is part of the original posters question is that you can put a 400w (or 2) closer to the canopy than you could a 600w light.

More variables. LOL

 

[zem]

If you can't explain it, how do you know it's true?

In the laws of physics, you can not say something is true or false unless you have proof.

Not an argument. Just the way it is on your planet.

I know it is true because i have run 2 400w lights side by side and used many sorts of lights, by first hand experience and not from studying physics.

 

[The Hemp Goddess]

This is just fact. Bwanabud's pic is valid. Putting 2 400W lights side by side does not make it an 800W--it is still 2 400W lights. A 400W light will penetrate x number of feet....regardless of how many of them you have. MR1 is correct with his comparison--kind of like the fact that 2 250W halogen bulbs will not throw light as far as a single 500W halogen. This could be demonstrated very easily with a light meter. I do not have one, but really anyone who understands how light works is going to understand that a given bulb is only going to penetrate so far regardless of how many of them there are.

 

[Hushpuppy]

Just my understanding off things I believe you guys are getting hung up on the definition of "penetration". According to the definition of penetration that we use here on the fforum, it is the distance the light will travel before losing a significant amount of energy. You cant think of it in total watts because as the light travels through the air, it loses energy.

2 400w lights at 10" away ffrom the canopy and sitting side by side will give more lumens to the canopy than 1 600w light. But if you back them up to 2' away from the canopy, The energy of each light will drop off, causing ffewer lumnes to reach the canopy, (and penetrate down into the canopy). But because the 600w light is driven harder (higher intensity), it will carry the same level of energy farther than the 400w.

you can think of it like having 2 waterhoses with spray nozzles on them. If you turn on the water to the 400w, it will spray only so far as the water disperses and doesn't travel as far, with as much water as when you turn on the 600w nozzle. It sprays harder than the 400w so it carries more water farther than the 400w.
Iff you have 2 nozzles spraying water from the 400w source, It will give more water than the 600w nozzle but at a shorter distance. At the farther distance, it loses the driving energy and much less water get out as far as does the 600w.

This is the same problem that we have with LED light. you can focus an LED bulb and shine it clean into space, but it won't carry the same amount of light energy as HPS lights.
It is a matter of energy dispersion and intensity (or drive).

I hope this makes sense to everyone

 

[goats_head_soup]

no matter how many 400s you use side by side you will only penetrate below the canopy 6 inches or so and 600 8 inches and 1000k bout 11 if I remember. So the taller you want your bushes go bigger. no amount of 400's handle a 5 foot tall bush or even 4ft. you might as well remove the bottoms all the way up. So 1000k will penetrate deeper than 4 400's side by side

 

[Landing]

you can think of it like having 2 waterhoses with spray nozzles on them. If you turn on the water to the 400w, it will spray only so far as the water disperses and doesn't travel as far, with as much water as when you turn on the 600w nozzle. It sprays harder than the 400w so it carries more water farther than the 400w.
Iff you have 2 nozzles spraying water from the 400w source, It will give more water than the 600w nozzle but at a shorter distance. At the farther distance, it loses the driving energy and much less water get out as far as does the 600w.

But see, that's where I think everyone is copying their definition of penetration off of everyone else.

Sure, the 400w hose wouldn't reach as far, but we're talking about an ENCLOSED space.

So, really, penetration = amount of water and the 800w wins.

My point is that if you hang the two 400w bulbs right next to each other, unlike with water, the light streams will increase and create an 800w light, with 800w of penetration.

If this is incorrect, I'd like to know why.

 

[umbra]

its called the inverse square law. as you double the distance from the light source, you measure the square root of the energy(lumens). as you triple the distance, you would measure 1/9 of the energy. it doesn't add more lumens. constructive interference of the wave fronts does not apply since none of it is phase matched

 

[Locked]

I am sorry we have not been able to explain it to your liking, but bottom line is two 400watt lights don't equal the penetration an 800 Watt would have if it existed.

 

[Hushpuppy]

Penetration is not about how much water is being sprayed, its about how far it will spray. The "inverse square law" is a law of physics that governs the properties of light energy penetration. That is why, if you have a light set up and you start by holding your hand 5' away, It will not feel warm, even though there is plenty of light shining on your hand, but the closer you place your hand to the light, the warmer it feels to you. This is because the light intensity is increasing exponentially as you get closer.

If you have a scrog grow where your canopy is set at one level that is only about 10" deep (or tall from the screen), then two 400w lights will give you more lumens to that canopy if kept within 8-10" of the tops, than one 600w light would give. I don't know any other way to make it any clearer. :confused2:

 

[umbra]

So if light follows the inverse square law, how come my outdoor plants dont have any problems with light penetrations?

The light from the sun travels 1,000's of light years. the distance from the top of the plant to the bottom of the plant is quite small compared to the total distance that the light traveled from the sun, so the plant does not see a difference in total lumens. Indoors this is different because of the relative distance from the light.

 

[Landing]

I am sorry we have not been able to explain it to your liking, but bottom line is two 400watt lights don't equal the penetration an 800 Watt would have if it existed.

If you haven't been able to explain it, then you must not understand it. In which case, a debate would fill that void. No?

Penetration is not about how much water is being sprayed, its about how far it will spray.

But my contention is that it is the same thing if you're filling up an enclosed area.

If you're trying to fill a 20 liter containers, then the 800w-equivalent would be superior.

In our case, we're trying to fill an enclosed 1 square meter of space, so whatever light doesn't penetrate at first will bounce off the sides of the space and continuously hit the canopy.

I mean, the light doesn't just disappear. If you have an 800w bulb or two 400w bulbs you have 800w of light, yes? So, if you position two 400w together, why should they have less penetration?

 

[umbra]

light is part of the electomagnetic spectrum. it is a wave form. a sine wave actually. there are troughs and valleys to the sine wave. if 2 lights' waves' troughs and valleys, do not line up with one another the total lumens are averaged and not added to each other. you never paid attention is science class

 

[bwanabud]

If you haven't been able to explain it, then you must not understand it. In which case, a debate would fill that void. No?

You can "debate" proven science all you want, but specialists in Optics have done the math....this is just bantering hi-jinx.

You're welcome to redesign the wheel too, but I'd advise to devote your time to a "better Mousetrap"...it would be worth millions, and still hasn't been done

 

[Hackerman]

its called the inverse square law. as you double the distance from the light source, you measure the square root of the energy(lumens). as you triple the distance, you would measure 1/9 of the energy. it doesn't add more lumens. constructive interference of the wave fronts does not apply since none of it is phase matched

Bingo!

That's the proof I was looking for.

Hey umbra, is your real name Mr. Baker and did you teach at MIT a thousand years ago? ROTFLMAO

So, now we know the answer to the original question. Sorry, all my threads seems to lead to arguments. LMAO But then, logical arguments are the basics for learning.

So, even though we have 2, 400w lights side by side and we are, indeed providing more lumens to the canopy (as Hushpuppy stated) we do not get more penetration to the lower areas where the 2 lights intersect.

You be da man, umbra.

 

[Locked]

If you haven't been able to explain it, then you must not understand it. In which case, a debate would fill that void. No?

It has been explained and I do understand it. You are the one who came here to ask a question and don't want to accept the answer. If you want a different answer just keep "shopping around" your question at other forums. Maybe you will get the answer you so desperately want.

But my contention is that it is the same thing if you're filling up an enclosed area.

If you're trying to fill a 20 liter containers, then the 800w-equivalent would be superior.

In our case, we're trying to fill an enclosed 1 square meter of space, so whatever light doesn't penetrate at first will bounce off the sides of the space and continuously hit the canopy.

I mean, the light doesn't just disappear. If you have an 800w bulb or two 400w bulbs you have 800w of light, yes? So, if you position two 400w together, why should they have less penetration?

Your contention is wrong.

 

[Hackerman]

It's all about the phase matching. If you could line up the sine waves it would penetrate like an 800w but since it is not matched, it's not cumulative.

umbra nailed this discussion to a close with the proper answer (at least for me).

 

[Hackerman]

LOL, it never stops with me.... all this reading of lighting makes me wonder what the benefit of a plano-convex (or negative meniscus) lens on the light hoods would do for distribution of light.

Things that make you go hmmmmmm?



Hey umbra, what do you know about the water solubility of canabanoids before and after decarboxylization? (is that a word?) LOL

 

[umbra]

his some technical info on decarboxy

Cannabis produces phyto cannabinoids in a carboxylic acid form that are not orally active at least at the CB-1 receptor sites, because they don’t readily pass the blood brain barrier in their polar form.

To enable them to pass the blood brain barrier, they must first be decarboxylated, to remove the COOH carboxyl group of atoms, which exits in the form of H20 and CO2.

Decarboxylation occurs naturally with time and temperature, as a function of drying, but we can shorten the amount of time required considerably, by adding more heat. The more heat, the faster it occurs, within reasonable ranges, and in fact occurs spontaneously when the material is burned or vaporized.

There is another mechanism at play however, which suggests that we need to control the decarboxylation temperatures carefully.

When we heat cannabis to convert the THCA and CBDA into THC and CBD, we are also converting THC to CBN at a faster rate. At about 70% decarboxylation, we actually start converting THC to CBN at a faster rate than we are converting THCA to THC, so as you can see by the following graph, after about 70% decarboxylation, the levels of THC actually start to fall sharply.

That of course means that the CBN also begins to rise and the medication is becoming more sedative.

Thank you Jump 117 for this excellent graph!

Decarboxylation Graph-1-1

Decarboxylation graph

Another fly in the ointment, is that we can never know for sure exactly what the starting state of decarboxylation is, so the times at temperature shown on the graphs are an average.

We can’t expect dry material placed in an oven at any given temperature to be that uniform temperature throughout instantly upon placing it in a heated oven, nor know for sure the state of decarboxylation by simple observation.

Decarboxylating plant material, also alters the taste (roasted/toasted), which some find less agreeable, and of course decarboxylating also evaporates away the smaller Monoterpenes and Sequiterpenes alcohols, phenols, ketones, aldehydes, ethers, and esters.

The good news is that it is dirt simple to monitor the state of cannabis oil decarboxylation placed in a 121C/250F hot oil bath, because you can watch the CO2 bubble production.

Just like the curves suggest, CO2 bubble production will proceed at its own observable rate. By keeping the puddle of oil lightly stirred on the bottom and in the corners of the pot (I use a bamboo skewer), so as to keep the bubbles broken free and floating to the top, you can tell exactly when the bubble formation suddenly tapers off at the top of the curve.

That is the point that we take it out of the oil for maximum head effect, and we leave it in until all bubbling stops, if we want a more sedative night time med.

Here are a couple pictures of what oil looks like when boiling off the residual butane. Residual butane or alcohol produces larger, randomly sized bubbles, and is fully purged, when they cease.

I am seemingly missing the middle picture of the CO2 bubbles, so I will add it later, but the second picture shows what fully decarboxylated oil looks like.



Residual solvent bubbles above:

Quiescent oil.
THC and other cannabinoids are not soluble in water

 

[MR1]

I have two 430w bulbs and ballasts and a light meter that reads foot candles. Test anyone?

 

[Hushpuppy]

OK here it is, an oversimplified explanation of light energy: light sources emit light in photons. These photons carry energy that is given to the plants for energizing their processes. Think of this energy as gasoline. These photons are gassed up like a car at the light source and then sent out to the plants. The trip across the space to the target (the plant) burns a certain amount of the gas that the photon has on board (If it was going through the vacuum of space(as opposed to traveling through earth's atmosphere) it doesn't burn any gas because there is no resistance).

The 400w light only fills each of the photons with 40gallons of gas while the 600w give the photons 60gallons of gas and the 1000w gives 100gallons of gas to each photon. If all three lights send out photons 3' through atmosphere to the plants, the 400w photon will burn up 35 gallons of its gas before it gets there, so it only has 5 gallons of gas to give to the plants. The 600w gets there but still burns up some of its gas, but it still has 15 gallons of gas to give to the plants. The 1kw photons get there and has 30 gallons of gas to give to the plants.

The plants need 12 gallons of gas from each photon to run their engines efficiently. So even if you have 2 of the 400w lights, the photons don't carry enough energy to go the distance (penetration) to the lower parts of the plants and still be able to give them the energy they need.

I oversimplified it and used made up numbers because I don't ffeel like doing all of the researching and calculating to get the actual energy numbers in joules(scientific unit of energy) but it is the same function of loss off energy over distance. I just used my numbers to illustrate the point of the energy loss because the statement, "the light doesn't just disappear". No the light doesn't but the energy does. It gets lost to the resistance of the air molecules which are heated by the energy that is lost as the photons pass through the molecules.

The same principal can be seen happening in water which is the same as air but far more dense population of molecules. The sun shines onto the ocean with trillions of joules of energy. Those photons are driven unbelievably hard by the sun, but the deeper you go into the ocean, the darker it gets. Not because the water is reflecting the light but because the molecules in the ocean are absorbing the energy from the photons as they travel through all those molecules. Eventually as the photons travel deeper into the ocean, they completely run out of energy and die. At that point, the ocean is dark.