knna

Hey, Quantrill, im glad you already mastered the sheet

It would be nice all the people input the data of its own bulbs and report it here.

Remember there is a lot of SPDs avalaible at Penguin's SPDs thread.

Good growing

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Bulb Analyzer Tool

Quantrill

Why don't you give us a brief explanation of the more important specs the sheet gives us. Maybe some ideal numbers to shoot for, or goals. I mean what kind of R/B ratio are we looking for? Whats a good lm / W
PPF / W
PUR / W
PPF / Klm
PUR / Klm
?


Thanks

__________________
Each man must for himself alone decide what is right and what is wrong, which course is patriotic and which isn't.

~Mark Twain

knna

Ok, here i go.

This sheet is designed to calc photosyntetic efficacy of each bulb. It dont calc the "best light", because there are qualitative issues, not computable. The more relevant is the blue content, because blue light penalize photosyntetic efficacy by two ways: have less photosyntetic efficiency and emits less photons per watt emited. But blue light is very relevant in order to grow health and productive plants. Because of this, the sheet provides the total blue emission. A reccomended level of blue is 30-40 uE/m2, but more blue have qualitative possitive effects, althoughit low the photosyntetic efficiency.

There are two mains parameters when considering each bulb efficacy for growing:

-Spectrum: emitting in the wavelenghts plants use more efficiently. The concept that explain it is PPF/PUR. As higher, better photosyntetic efficacy of the spectrum alone.

-System efficiency/Watt: the efficiency of the system bulb+ballast in converting light from the imput energy (system electric comsuption). Here is where larger differences exist, thus, its the more relevant parameter.

Until now, mixing both concepts was a qualitative analysis. The sheet weight both and provide accurate photosyntetic efficacy.

PPF/W: How many photons the bulb emits per watt comsumed. The reason to give it per watt is to do comparision between differents wattage bulbs possible and easy. The highest the better. Currently, 1,5 uE/W seems to be the line wich split between good bulbs and not so good. This is an objetive parameter, there is no any subjetive calc implied, so PPF is the main measure used in botany.

PUR/W: This is the measure of true photosyntetic efficacy. Corrects PPF for the relative leave's absortion of each wavelenght, aswell for the relative photosyntetic capacity. This is the final goal of the sheet, as provide in a single figure a summary of all the parameters implied. In order to do a list of best bulbs for plants, this parameter would be the used as a reference of best and worst. The higher the better. Any figure over 1 is good, but the 1,2 figure correspond to top end bulbs.

There is a problem with the PUR figure, as it implies a correction with the plants quantum yield, and there is no any study to compute that for cannabis, so the correction factor is calculated indirectly, so it implies some subjetivity.

The PPF/Klm and PUR/klm just are provided to compute PPF and PUR from lux data in real measurements. Sunlight is about 16,8 uE/Klm. HPSs are around 12 uE/klm, while MHs are around 14-15 uE/Klm and standard floros between 13-15 uE/Klm.

The Red/Blue ratio is provided to help in qualitative analysis. Its difficult to say whats the best. Anyway, it depends of the plant's developing stage. NASA scientifics works with R/B of 9 as optimum, but it probably depends of the plant specie. I believe any ratio below 10 is good for vegetative stage, preferably in the 3-6 figure, while in flower it depends of the total irradiance used, but a R/B ratio between 8-16 seems good. As general guidance, as higher the irradiance used (uE/m2), the R/B ratio must be higher.

Peace and good grows

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Bulb Analyzer Tool

Quantrill

Dude, You Rock!


Ok, so PPF gives each photon an equal weight? and PUR tries its best to give accurite weight to each photon according to marijuana's ability to use it for growth?

If I have a light meter, I can use its measurements in photmometric terms in conjunction with the PPF/Klm and PUR/klm data from the spreadsheet to calculate the actual amount of energy falling on any given spot in the grow?

__________________
Each man must for himself alone decide what is right and what is wrong, which course is patriotic and which isn't.

~Mark Twain

knna

Yes, PPF is Photon Flux, is a count of photons, simply. The unit uE is equivalent to micro mols of photons. A mol of any thing is 6,0221415*10^23 (yep, a 6 followed by 23 zeros) particles, in this case, photons. A micro mol is the 1/1000000 part of a mol, so each uE is about 6 followed by 17 zeros photons per second.

PPF relates to bulb emission, an absolute measure. Another thing is how this photons reach the plant, the irradiance, wich relates to the surface receiving the light. This is the measure wich changes depending of the bulb distance, with no reflectorized bulbs, it decreases with the square of the distance (square law). This measure is Photon Flux Density, PPFD, wich correspond to uE/m2, its one radiometric equivalence of flux, wich unit is the lux (=lm/m2), and this is what luxometer o photometer measures. To convert from lux to PPFD, just multiply it (in Klux=1000lux) by the PPF/Klm data in the sheet, and you obtain irradiance uE/m2 (what expensive photon count detectors measure with less accuracy).

PUR correspond to Photosyntetic Usable Radiation, its a adimensional measure, as its PPF weighted by plant's absorbance and photosyntetic action of each wavelenght. I use "pur" as "unit". PURD can be obtained from lux data the same as PPFD, multiplying the Klux measure per sheet's PUR/Klm.

Why obtain this adimensional data? Because its the measure wich can give an accurate measurement of light used in a grow, independ of the kynd of light used, opposite at PPFD. Give up watts/sq ft, lm/sq feet, whose indications are only valid for one type of light and wattage.

We can say: MJ needs 20000 (=20K) purd in order to flower. MJ reach its maximun photosyntesis capacity at 30K purd, and reach saturation point at 60 purd (these are improvised example levels, apart each strain is a bit different in this), and these are valid data independent of the light used, in quality and wattage: for example, an average 30K purd at canopy can be reached with a 400w HPS in 15 sq ft, with 600w of 32 w of CFLs, or with 400w of T5s floros (again example invented level). The sheet is the tool to calc how many watts of the light we are going to use are needed to reach the PURD level choosed, or calc the grow area a specific bulb can cover at the PURD desired level.

Astract: yes to the three Quantrill questions

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Bulb Analyzer Tool

Quantrill

Bravo! Bravo!


It really is a great tool! With the spreadsheet doing all the math, the hardest part is resizing the SPD graph so that the superimposed grid has the proper number of horizontal boxes per 5 or 10 nm increment, and then counting the vertical grid boxes to come up with the data to input into the spreadsheet.


Voila! valid info to evaluate your light source.


Did I say thanks and great job knna yet? Great job knna, Thank You for doing the hard part.

So what kind of PURD and PPFD are you growing with?

__________________
Each man must for himself alone decide what is right and what is wrong, which course is patriotic and which isn't.

~Mark Twain

knna

Thanks for your kind words, Quantrill.

Im very glad my work is useful for the people. I would like more people try to analyze their bulbs, and specially, report the yields at each PURD (true measurements) or at least, PUR/sq ft, in order to know the MJ best light grow ranges.

I think maybe im too much technic in my explanations, but i dont mind to explain things from the beggining if people wants. But seems many people become frightened in this thread.

Nobody born knowing all. PLEASE, ASK FOR ANYTHING YOU DONT UNDERSTAND. Dont be afraid of ask, think that most growers dont have any knowlegde about light, and asking is the way to learn.

Im very happy that Quantrill has learnt to use the sheet (i talk in 3th person when maybe just Quantrill and me read this thread ). It seems difficult at first, but in fact its very easy to use them.

I dont know exactly, but as i grow with fluos, i can stimate it very well.

Total PPF is 236 uE in 0,44m2 (4,9 sq ft). Reflector losses are about 15% in my setup, so there are about 200 uE reaching plants. It mean an average 454 uE/m2 (absolute radiance, not PPFD). I calc irradiances are between 240 and 480uE/m2. This short range is because i grow with CFLs in SOG, HID give a very uneven lighting, beeing larger difference between max and min PPFD.

I use a low PPFD, due to my setup caracteristics, and because i seek for max gr/watt. You will find lots of growers having 1500uE/m2 here. This stimated PPFD reports me about 16-18gr/sq ft each 7-8 weeks.

The PUR/PPF of my bulbs are 0,67. Multiplying PPF for this factor, obtain the equivalents PUR info.

Im saving my money from buying a luxometer because i want to buy a best light measurement system

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Bulb Analyzer Tool

knna

As i finish the last post, i realized a great application of using PUR: give up with productivity ratios given related to watts used (0,5 gr/w, 1 gr/w, etc).

The gr/w ratio is very injust with low scale growers, as low wattage bulbs are always less efficient than high wattage ones. If one CFL grower, using 23% efficiency bulbs, obtain 0,4 gr/w and other grower, using high watage HPS, with an efficiency of 38%, obtain 0,7gr/w. Who are obtaining more for photon used? This is the relevant question, how to obtain more for the same light. Comparing 32w CFLs and 1000w HPS is like comparing apples and bananas. Both fruit, but anything else in common.

Using PUR allows to compare grows productivity independent of the spectrum and the efficiency of lights used.

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Bulb Analyzer Tool

afterburner

Wow you guys. Great discussion. I'm in way over my head now

Keep up the good work


-ab

Water_Boy

Ya, like AB said.....


Thanks Guys!!