New LED lights stretching

Kassiopeija

Kassiopeija

Well-Known Member
grotbags said:
haha i knew you would pick em to bits...:D
Click to expand...
my initial response got deleted before posting, I want to add that the second .pdf held a nice spec about water absorption (showing the depths)
imagine now algae adopting to all these various colors or specs, for 2.5bn years until life went onto land..

the one commentator is essentially right all of this is already known. but books that go very deep into it are costly and hard to comprehend. even alot of studies are skewed when they only show a very narrow "side if the story".
 
Rocket Soul

Rocket Soul

Well-Known Member
jimihendrix1 said:
I got the spectrum chart from the HLG site.

This was a comparison of a LUXX 645 Pro vs the Gavita 1700e. They say the Gavita has a 3000k spectrum. LUXX is 3900k


#4 Luxx vs. Gavita LED Light Spectrum
If light output is like your cars horsepower, then light spectrum would be the handling. Choosing the appropriate light spectrum, or using a grow light controller to adjust your light’s channels will determine how your plant will grow. Both Luxx 645 Pro LED and Gavita 1700e are extremely similar in the light quality they produce. The Luxx uses a 3900 Kelvin light spectrum, while the Gavita 1700e uses a 3000 Kelvin spectrum with additional 660 nanometer (nm) Osram red diodes to balance the spectrum for full-cycle production. You’re not going to find much difference in terms of spectral performance from these fixtures, again making both good options for cultivation at any growth stage.
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Thats not the spectrum from the hlg site though, this is the revised spectrum:
HLGADVScorpionDiabloSpectrum1600x1600_rnd_360x.jpg
The difference is not as visible as the one i posted as this light meter has a different scale and detail but you cna fairly easily see that it has more 660red and a slightly "fatter" blue spike. The other spectrum i posted is from the independent ppfd report under the diablo scorpion, more detailed and valid.

Also: "while the Gavita 1700e uses a 3000 Kelvin spectrum with additional 660 nanometer (nm) "

If this statement is right then the spectrum you posted is not right. 3000k 80cri white does not have a blue spike that high. Sorry but either the comparison or the spectrum is not right.



Wow, i seem to be ranting by now.

As stated i dont have a horse in these race it feels like i might be bashing on you, please, im not, im just hoping to help you get you better informed regarding your light purchase.
 
PJ Diaz

PJ Diaz

Well-Known Member
Kassiopeija said:
Emmerson effect is about the abnormal increased excitation
of photosystem 2, which can happen with any PAR white light <681nm, and its counterbalancing via PS2, that absorbs also all PAR light, but accepts light more redshifted, thus the darkred/farred colours serve to stimulate this - in the presence of other PAR light.
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Huh? White light below 681nm??

Emerson effect - Wikipedia

en.wikipedia.org en.wikipedia.org

"The Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to light of wavelength 680 nm (deep red spectrum) and more than 680 nm (far red spectrum). When simultaneously exposed to light of both wavelengths, the rate of photosynthesis is far higher than the sum of the red light and far red light photosynthesis rates. The effect was early evidence that two photosystems, processing different wavelengths, cooperate in photosynthesis."
 
Kassiopeija

Kassiopeija

Well-Known Member
PJ Diaz said:
Huh? White light below 681nm??

Emerson effect - Wikipedia

en.wikipedia.org en.wikipedia.org

"The Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to light of wavelength 680 nm (deep red spectrum) and more than 680 nm (far red spectrum). When simultaneously exposed to light of both wavelengths, the rate of photosynthesis is far higher than the sum of the red light and far red light photosynthesis rates. The effect was early evidence that two photosystems, processing different wavelengths, cooperate in photosynthesis."
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yes white light
that Wikipedia article is unfortunately misleading
I read through Emmerson's original work and he didnt use monochromatic light-sources but broadbands which was cut off by blends on one side of the spectrum

I mean why do you think light in the range of 400-630nm wouldnt excitate PS2?
 
PJ Diaz

PJ Diaz

Well-Known Member
Kassiopeija said:
yes white light
that Wikipedia article is unfortunately misleading
I read through Emmerson's original work and he didnt use monochromatic light-sources but broadbands which was cut off by blends on one side of the spectrum

I mean why do you think light in the range of 400-630nm wouldnt excitate PS2?
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I'll have to go back and read his work myself I guess. Thanks for the tip.
 
Kassiopeija

Kassiopeija

Well-Known Member
books.google.com

Stoffwechselphysiologie der Pflanzen

Standardlehrbuch eines wichtigen Prüfungsfaches. Setzt erhebliche chemische Kenntnisse voraus, deshalb vor allem für Hauptfach-Biologen. Für diese aber notwendig. Auflage gegenüber der 5. (ID 48/88) erheblich verändert, so wurde auf eine allzu detaillierte Beschreibung mancher komplexer...
books.google.com

page 108:
Screenshot_20220301-200404~2.png

Important is the notion:
"<670nm" while it set the other wavelength to "=700nm".
So anything that is shorter in wavelength than 670nm. Actually it's 680nm as that is the max of p680 - the core of PS1. (the book is 20 years old...)

It is the darkred light that has the tendency to excitate PS1 - with what kind of light you excitate PS2 is irrelevant, though 660nm is best for highest absorption simply.

Here is a photo out of L. O. Björn's "Photobiology"
IMG_20220301_202021~4.jpg
that shows the differences of PS I vs II.
II absorbs everywhere better except at the darkred end of the visible spectrum.
 
C

cage

Well-Known Member
I'm sure I missed some of the atleast somewhat related discussion :)

Small note on the original light of the topic.
1 COB unit has 60x3W diodes, so my 1 unit has 360W of diodes and 2x of them so 720W of diodes ran at 250W(125W each).
And no I didn't pay 500e for them :)
Untitled.jpg

I'm probably just going to keep my veg light for start of flower and add 2x of those after some of the stretch period has gone. Veg light is 115W mostly blue, so that would bring the total LED lightning (from wall 365W).
I got 1x 600W HPS setup running and I would have another 400W HPS setup, but I figure they should atleast compare to the 400W HPS..

*edit The company also had these lights custom made for them. So I guess that would indicate above china quality.
 
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D

Drasik

Active Member
grotbags said:
@Kassiopeija i seen these posted on another forum and thought you might find them interesting,

https://www.quantamagazine.org/why-are-plants-green-to-reduce-the-noise-in-photosynthesis-20200730/

http://www.esalq.usp.br/lepse/imgs/conteudo_thumb/Why-did-chlorophyl-evolve-to-be-green-as-opposed-to-black.pdf
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Interesting but none of them are papers. I read the second one but it wasn't providing any specifics details for evidence, mainly jammed a bunch of theories together. Interesting read there are def theories that can be tested. Plants have evolved hormonally to really enjoy red and blue for their energy consumption.
 
Kassiopeija

Kassiopeija

Well-Known Member
Drasik said:
Interesting but none of them are papers. I read the second one but it wasn't providing any specifics details for evidence, mainly jammed a bunch of theories together. Interesting read there are def theories that can be tested. Plants have evolved hormonally to really enjoy red and blue for their energy consumption.
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true but it's just that this
Leaf-Transmittance-1024x446.png
is a real problem, but outside the sun delivers similar light-strength no matter how tall the plant is. and moves around. and delivers a huge portion of its energy via diffuse skylight, deflection light from other plants plus transmittance of 2000ppfd is higher esp. given leaves grown in such high irradiance allow a higher transmittance by its altered structure.

it's kind of nonsense to have a spectrum consisting of colors where 95% of total radiation will absorb at the very first top leaves. most of these photons will just be quenched non-photochemically.
IMG_20220307_023739~2.jpg
it's the deep canopy aspects where many studies on green & farred supplemental light show enhanced total harvest dry mass, even when other studies (on single isolate topics like photosynthesis rate on a single leaf or stomatal conductance etc) show non-optimal, sometimes even adverse, behaviour.
 
grotbags

grotbags

Well-Known Member
Drasik said:
Interesting but none of them are papers. I read the second one but it wasn't providing any specifics details for evidence, mainly jammed a bunch of theories together. Interesting read there are def theories that can be tested. Plants have evolved hormonally to really enjoy red and blue for their energy consumption.
Click to expand...
they were not presented as papers.
 
D

Drasik

Active Member
Kassiopeija said:
true but it's just that this
View attachment 5097297
is a real problem, but outside the sun delivers similar light-strength no matter how tall the plant is. and moves around. and delivers a huge portion of its energy via diffuse skylight, deflection light from other plants plus transmittance of 2000ppfd is higher esp. given leaves grown in such high irradiance allow a higher transmittance by its altered structure.

it's kind of nonsense to have a spectrum consisting of colors where 95% of total radiation will absorb at the very first top leaves. most of these photons will just be quenched non-photochemically.
View attachment 5097305
it's the deep canopy aspects where many studies on green & farred supplemental light show enhanced total harvest dry mass, even when other studies (on single isolate topics like photosynthesis rate on a single leaf or stomatal conductance etc) show non-optimal, sometimes even adverse, behaviour.
Click to expand...
Where did these charts come from and what was the context for these measurements. Also what do you mean by the "sun delivers similar light strength"?
 
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