knna

I forgot to mention: to check the new sheet, just copy and paste the SPD column of the old sheet, aswell as the watts/Klm data.

In the documentation process toward the new version, i found detailed info about the Inada and McCree curves.

One info very relevant is 30years ago Inada did the same im doing now, but cheking the calculated result (for photosynthesis, the PUR data) with on field measurements, getting that the metodology used (suppouse that the total photosynthesis is the sum of photosynthesis produced by each separate wavelenght) provide meanglifull results, with error margin around 7%. So enhancement (sinergistic) effects, affect little.

In the same trend, extrapolating the sheet results to a full canopy, and not only the top, is more complicated and need complicated corrections for each type of canopy. Anyway, its out of the purpose of the sheet, wich only tries to give a reference about the efficacy of bulbs for growing.

As noted before, the McCree curve is refered to absorbed photons. At least, the widely used one. What confused me was the fact that in many horticultural pages they apply the McCree curve directly to SPDs, and thats a wrong methodology way (mix differents units). It have an explanation, the difficulty getting the methodology used to build the curve: i started to research the topic two years ago and i found that info recently.

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Fafhrd

Major kudos to Knna and team.


I've been researching this very subject for the last six months or so, and stumbled across this particular thread from a google search for "plantastar spd". Wish I had found it sooner, as it covers much of what I've struggled with figuring out, in a very direct and understandable way... least for me.



THIS SHOULD BE A STICKY!!!


I can't believe it's not... I've not seen anything at any of the canna sites that comes anywhere close to this...

Professionally done, well thought out... an invaluable resource that can only get better with refinement and addition.



Knna... I've read many of your posts here and on other sites, regards LEDs... I too have a interest in LED lighting, (and hope for it). I've found your posts about them and photobiology to be incredibly informative and enlightening... hats off and a very big Mucho Gracias! for your efforts and community spirit.



As an aside...

I have access to a ILT 400 Radiometer/Photometer,

IL1400A Radiometer & Photometer — International Light Technologies Inc


and have played around with it a fair amount... I'm hoping that in the near future I can afford the Par filter and sharp cut filters,

Plant Photobiology Light Measurement Systems — International Light Technologies Inc

for more accurate measurements of uE and spd specifics... I hope to contribute back to the community soon.



I have some baseline measurements from some LED experiments I've run... but have put the bench aside for a bit now, as my grow and life have taken precedent.... I hope to have some spare time soon to revisit the bench and my tests and compile and share my results.


much regards and THANKS again,

fafhrd

LJB

knna, I'm having some trouble understand your analyzer tool.

Specifically with the 400w Philips CMH, can you say what the % distribution within each color waveband is?

Looking at the chart your program creates for the CMH, where did you get the number - red to blue ratio of 4?

I've read through a lot of your posts.

Don't know if you've seen this before, if not, thought you might be interested in table 3:

L.B.Prikupets & A.A.Tikhomirov - OPTIMIZATION OF LAMP SPECTRUM FOR VEGETABLE GROWTH

LJB

knna, another link for you to look at if you haven't before:

RE: PAR, Lumens, Watts, etc

Aqua Botanic-light bulb comparison

MPAR

Is the same thing as your own system?

knna

I actually dont remember where I posted the CMH data. But currently I have it in the new sheet format (check link in my signature), and it shows a R/B ratio of 1.41 (PAR Watts) or 2 (uE). Its calculated dividing output between 600-700nm (Red) by 400-500nm (Blue).

Percentages of each band (W-uE)

Blue (400-499nm): 25.24%- 20.29%

Green (500-599nm): 39.17%-38.75%

Red (600-699nm): 35.6%-40.96%

Those link have been already posted in the thread. I based the sheet on the articles of Ivo Busko, although I modified their procedures for better accuracy. I think that the curves that weight uE for its photosynthetic potential are more accurate on my sheet, aswell as the method for obtaining energy efficiency (although its basically the same).

As for the rest, we sometimes use different terms, but they refer to the same.

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LJB

http://www.gardenscure.com/420/light...tml#post907594

CMH data on page four of this thread from yourself and quantrill

This tool is extremely valuable, thanks for sharing it and for posting those percentages.

I've read elsewhere...

https://www.cannabis-world.org/cw/sh...9092#post59092

...that you came up with a quantum yield curve for c.s. but the link to a post on "hempcultivation.com" is dead.

Would love to see that graph!!!

knna

Ok, thanks, I looked for it but I was looking for "CMH" so I didnt see it. Results for the new format of the sheet are almost identical.

The division between veg and flower spectrums on the R/B ratio of 4 is just an empirical observation: spectrums used traditionaly for veg have usually R/B of 3 and lower, while those used for bloom have R/B over 4, very often way over it (8-12). Anyway, I actually doubt traditional thinking of what MJ likes for veg and flowering is right.

The thread linked in CW is this one. This site was "hempcultivation.com". The link to the brief QY thread is on the first post of this thread.

Since I wrote that thread about cannabis QY I learned a lot more. Now I know that QY curve has many limitations and that is only useful as orientative way of weighting spectrums. Its not valid under photosynthetic saturating irradiances, and not take into account plants adaptability. But continue being the better way of weighting spectrum. Simply its not possible to do accurately it for all irradiances levels and light's qualities.

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