GrowLightResearch
Well-Known Member
I said that only becasue a particular study I read on lettuce used florescent as a control and it did better than BR. BRW did best and had superior sweetness.
Can a light get too efficient
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PSUAGRO.
Well-Known Member
................maybe he's secretly a full house fan instead of osram? oslons are tiny ass little diodes, not good for angry/shaky hands
wietefras
Well-Known Member
Heh makes sense. Better go for Olsons instead then
shaky hands
That's probably what the lettuce is for too.
alesh
Well-Known Member
I only found 4T-2U. Is there a chance for them to actually be 2U?
I think if they have a high yield of 2U bins, they would separate them and charge a premium. but who knows maybe ask an osram tech ?
mahiluana
Well-Known Member
the peak of 637nm is close to Mr. Mc Cree PAR - so i agree with the spec for the first look.
But i`m convinced that a deep gap in the cyan(485-505nm like always with white phos. led chip) is still nothing else than a problem of phosphors and has nothing to do with photosynthesis.
I like to eat carots - and carotenoids are an important part of my life and my plants.
Weed contains more than a dozen of different carotenoids, that peak in different wavelenghts.
Many of them absorb @400-550nm and i don`t want to miss any of them.
I`m much more confident in the spectral holistic of the sun and the evolutional process of plants.
Much less in grow light concepts of cree,citizen, epileds etc...........and so the whole debate about chlorophyll as a main actor in photosynthesis imo get senseless --- if finally we could drive our leds with a good, efficient overall spectrum like the real
solar radiation spectrum.
In a natural daylight cyan 490-510nm is one of the most intense & present wavelenghts inside 400-700nm range. Natural sunlight has a constant overall presence in this range, that is called
CRI100
I would suggest to mix/fade your 637nm spec with a led that carry the same red phosphored silicone layer, but is exited 50% by 450nm blue leds and 50% by 490nm cyan led.
Or even a mixture of 3, 4, or more wavelenghts in between a 400-500nm range.
Chips of these wavelenghts have all the same Vf and it is not necessary to use seperated channels.
There must be an important switch between 470nm and 490nm as you can see in the pics.
while wavelenght of 400nm, 425nm, 450nm, 470nm all get converted to ~ the same magenta red ---
the cyan led shows clearly green and amber and looks like a more neutral or even coolw. spec.
to my eye. To mix the light of 450/637nm with 490/600nm should result in better Cri !and! better coverage of the carotenoids.
left 3w 490nm cyan led // right 10w 470nm blue led
--- both covered with the same thin silicone layer of a red phosphor chinise chip.
both - or multiple specs(400-500nm) together should reach much better CRI and imitate sunlight a bit closer to perfect.
So what do you think about my concept ? ------- Does it work ?
Or is there any physical reason why most of the white chips are made with a 450nm led under the phosphor layer ?
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I'm really tired of trying to explain things to you. I strongly suggest you do more study and get up to speed on lighting for cannabis. Search out @stardustsailor always a good read for those smart enough to know what he is talking about.
Too many photons are being ABSORBED by the UPPER chloroplasts inside the leaves of the TOP part of the leaf canopy => Overload of energy => light saturation => Non-photochemical quenching => excess energy from photons is turned into heat and fluorescence in the IR region .
When leaves are exposed to greater than saturating light ( energy = power x time =DLI ) ,
the excess light energy absorbed at the top of the leaf must be dissipated as heat.
Heat dissipation at the leaf surface is feasible, and evapotranspiration is a major component of
such dissipation of energy. Any number of possible heat dissipation mechanisms may be involved (Demmig-Adams
& Adams 1992; Sun et al. 1996b). Indirectly, non-plastid absorption by cellular components decreases photosynthetic action (Strain 1950; Inada 1976); and xerophytes tend to have PM that are decreased in diameter, thereby increasing their cell wall per plastid (Shields 1950). The increase in cell wall may afford protection, as cell walls, while being somewhat transparent, also absorb light (see Strain 1950, 1951); they also may aid in transmission of light more deeply into the leaf. Future research aimed at understanding the specific mechanisms that control energy dissipation across the leaf will be enlightening.
The presently evolved absorption characteristics of higher plant Chl’s a and b
allow optimal photosynthesis under saturating and non-saturating light conditions. Under
high photon flux, the blue and red light are efficiently absorbed in the upper part of the leaf.
Since NPQ is linked to light absorbed by Chl and carotenoids, blue and red light absorbed at the top of the leaf must contribute mainly to such quenching when it is induced.
Green light absorbed at the top of the leaf will also be proportionately dissipated.
Thus, light absorbed by Chl and carotenoids at the top of the leaf protects the lower region of the leaf from high photon flux. In particular, the blue light, will be ‘screened’ out and its energy will be dissipated as heat
(see Fig. 7).
In contrast, deep within the leaf where light fluxes are decreased, and there is a strong correlation between the green light gradient and carbon fixation ( no bubbles there for Mr.Engelmann )(Fig. 5c), NPQ will be disengaged; and green light will efficiently drive photosynthesis (Sunet al. 1998 ).
It appears that the particular complement of photosynthetic pigments in higher plants evolved to maximally utilize green light
Sun et a. 1998 ).
Instead of having a maximum extinction in green light, however, higher plant photosynthetic pigments exhibit the lowest extinction in the green. Hence, modulation of green light absorption by leaves and the leaf canopy can occur by varying leaf thickness and the Chl content in leaves, whereas red and blue light absorption varies relatively little (e.g. Rabideau et al.1946; Strain 1951; Moss & Loomis 1952; Inada 1976; seeFig. 7).
( At this point the whole "secret" about green light is revealed ! )
http://www.esalq.usp.br/lepse/imgs/conteudo_thumb/Why-are-higher-plants-green--Evolution-of-the-higher-plant-photosynthetic-pigment-complement.pdf
Green light to you -up till now and if I've understood correctly -is "waste".
For me and a bunch of others is the "main fuel " ,since most of us aim
for high PPFD figures ,constantly for 12 long hours .
I always thought royal blue diodes were used because of their high efficiency. Biggest weakness of white phosphors driven by royal blues for plants, especially Cannabis is the complete lack of light in the UVA and actinic range (350nm to 430nm). Even ordinary fluoros do better in this region.
Gotta have some 420 's
Schalalala
Active Member
GrowLightResearch
Well-Known Member
What has convinced you these cyan wavelengths are important?
These are wavelengths are not used because they are not needed and not as efficient. White LEDs are made for illumination markets not horticulture.
450nm is the sweet spot for Indium Gallium Nitride LEDs (InGaN). 450nm is used for its photoluminescence properties.
White LEDs are like black light posters. When the UVA (black light) strikes the phosphor on the poster, the color is changed (wavelength converted) by the phosphorescent ink. It's not a reflection, the photons are absorbed and a few nanoseconds later are re-emitted at a different wavelength. When you turn off a white LED in a dark room it may look like it is still dimly lit. that is the phosphor still emitting photons.
Most all of the R&D goes into the 450nm deep blue LED and red phosphors. That's why it is the most efficient LED at converting electrons to photons. There are very few uses for green LEDs other than a stop and go light and RGB displays. Green is the least efficient LED because less R&D is spent on green.
Blue LEDs were introduced as very dim Silicon Carbide (SiC) LEDs. Gallium Nitride was then grown directly on the SiC substrate for an 8x boost in output. Recently (10 years ago?) a layer of Indium was added for a more than 12x boost in output.
Green can also be created natively with the same type of LED (InGaN) as deep blue but the band gap is wider and requires more energy for electron to jump the gap causing a shift in chromaticity.
Blue photons carry more energy than reds so it take more energy to create a blue. That is why blue (white, green) LEDs are ≈3v and red are ≈2v.
The phosphors in a white LED are a combination of RGB phosphors. When the wavelengths are converted the larger the difference between deep blue and the re-emitted color the less efficient the conversion becomes. This is why lower CCT, higher the CRI, and more red equate to lower efficiency.
For purposes of photosynthesis blue has more energy than a plant needs. When a pigment is excited with a blue photon it must lower the energy level before transferring the energy to the carbon reaction center.
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GrowLightResearch
Well-Known Member
I do not know exactly what that means. You think a sun spectrum is better than LEDs? That is very reasonable and logical thinking. Unless you want kick ass cannabis.
There seems to be a lot of confusion between light being used for photosynthesis PPF and Biologically Active Photon Flux (280-800nm, e.g. UV and Far Red). There are pigments that absorb photons for photosynthesis and then there are photoreceptor proteins (e.g. phytochromes).
I have not heard much said about secondary metabolites on RolliTup. There are primary metabolites (e.g. amino acids, sugars, lipids) and secondary metabolites (e.g. cannabinoids).
Secondary metabolites are used by the plant mostly as attractants (e.g. bees) repellents (e.g. microbes) that affect taste, aroma, and medicinals.
There are 3 types of secondary Metabolites: Terpenes, phenolics, and nitrogen compounds. Of interests are the terpenes and phenolics. These are the targets of GMO and more recently photomorphogenesis (e.g. grow light research).
For examples: When a plant is attacked by insects, after the attack begins the plant produces terpenes such as monoterpenes and sesquiterpenes. UV light activates the biosynthesis of phenolic compounds. A virgin female cannabis produces cannabinoids to attract bees and make viscous oils for pollen to stick to.
It has been recently discovered that LED lights can modulate the biosynthesis of terpenes, phenolics. Sunlight does not invoke this activation. Plants have evolved under sunlight and adapted.
In the following image notice how the first column GH (green house sunlight) activates very few secondary volatile compounds. Blue does worse. Red about the same. Where it gets interesting is in Blue-Red-Green, Blue-Red-Yellow, and Blue-Red-FarRed.
My current hypothesis is LEDs can make better cannabis than sunlight. Goes against logic and reason, but that's me.
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GrowLightResearch
Well-Known Member
I do not need you to explain things. If I annoy you, add me to "People You Ignore".
So is this the example of why you think you have issues with transmittance and penetration?
That stuff may apply to certain species and not cannabis unless the research was specifically conducted on cannabis. If you suspect this is an issue you need to measure.
I apologize for my reaction to McCree. I am sick and tired of hearing about an antiquated study done 50 years ago using crude methods. I am especially annoyed by the way McCree studies are twisted to sell grow lights. 90% of what I read about McCree is fabricated bullshit and misinterpretations. It gets real old. For Christ's sake the guy sandwiched a piece of leaf between a two kitchen sponges. I give him credit for doing that and making his experiment repeatable and therefore scientifically valid.
But on the other hand Engelmann did a very relevant study in 1882. Engelmann's light seeking bacteria made a much better graph than McCree. McCree had limited resources in the 1960s. Since then, with much more modern equipment and methods McCree's plots have been refined and now look more like Engelmann's bacteria. Look at McCree's peaks of RQY at 600 and 625 nm. The peak has been since then found to actually be at 680 nm.
Speaking of Quantum Yield WTF is so difficult to understand???
QY = photochemicals produced ÷ photons absorbed.
This means if 800 photons are absorbed and 100 oxygen molecules are produced the QY is 100% at green. If 800,000 absorbed red photons create 100,000 oxygen molecules red's QY is also 100%. if the 800 photons of green produced 10 oxygen molecules green's QY is 10%.
Quantum Yield is NOT about the number of photons absorbed!!!!!!!!!!!
Quantum Yield is what is done with the photons AFTER being absorbed.
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GrowLightResearch
Well-Known Member
It's not a matter of if it works. It's a matter of efficiency.
A 380-400nm UVA light source will render 100CRI with a nearly 100% efficient phosphor. The problem is a 380-400nm LED is expensive to manufacture.
An LED manufacture has two criteria in choosing the type of LED (e.g. InGaN) and its efficiency and secondly the CRI.
The most efficient white phosphor LED is a 450nm LED with yellow phosphor.
I found no research on a phosphor pumped LED over 460nm.
A cyan LED is a InGaN LED with a wider band gap between the anode and cathode materials. A wider band gap increases the wavelength but also requires more energy to jump the wider gap which means less efficiency. I would guess that a cyan LED would have less fluorescence if any.
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Now you truly have shown how dumb and egotistical you are. Thinking that you can create a spectrum of light better than the sun, which the cannabis plants has evolved with at least as far back as biblical times.
GrowLightResearch
Well-Known Member
I said it's a hypothesis. Do you not now what a hypothesis is? Or am I too dumb to understand what that means?
Does it hurt to try? You cannot succeed if you don't try.
The impossible is only impossible until someone does it.
It's only those that try to change the world that are the ones that actually change the world.
Is that egotistical? I don't think so. It an attitude that has worked well for me and my kids.
That first column (GH) green house sunlight looks pretty dismal compared to the BRY.
But hey, it's your life do with it what you want.
I have no idea why you have the desire to put others down but I'm not about to let your problems become my problem.
Please add me to your "People You Ignore".
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GrowLightResearch
Well-Known Member
TROLL ALERT
I said:
The troll says:
People of normal intelligence should have no problem understanding what I said.
An intelligent person says:
Alesh was referring to the Olson SSL Hyper Red datasheet.
_______________________________________________________
And to those previous posts regarding the Luxeon Red Meat measurements the troll has been trashing, Alesh said (after comparing the measurements the troll trashed) to his Math Behind numbers :
Things a Troll says:
The troll thinks Olson is a typo.
Heh makes sense. Better go for Olsons instead then
Meanwhile back in reality:
Olson SSL series is not that new, released about two years ago.
This is from the latest Rev 2 datasheet released Nov. 2017.
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alesh
Well-Known Member
I don't think it's dumb. Plants have been evolving under the sun in order to survive and multiply. We (at least I) want them to produce larger quantity of better product. Is it really impossible that it could be achieved under different spectrum of light?
Plants outside have evolved to thrive in the world where the weather changes and there are droughts, heat waves or freezes. And yet, we've found that stable, controled climate somehow grows better plants.
Not to mention that a lot of strains we're all growing today have been through many generations of selective breeding under artificial light.
