White LEDs?

AirAnt

AirAnt

Well-Known Member
churchhaze said:
You're just digging your grave deeper by implying that those of us who use whites are the lowest common denominator. You're really not going to make any friends that way, and you don't look very smart comparing yourself with some of the very bright posters on this forum who are currently experimenting with whites, whites+reds, whites+730nm, etc.
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jeanlucpicard'ohcomeon'.gif

I'm not saying you're the lowest common denominator, I'm saying mass manufactured white LEDs are. Now I know you're being intentionally obtuse and I'll stop posting in what is quite clearly a troll thread.
 
Yodaweed

Yodaweed

Well-Known Member
White LED's work great a lot of people use 2700-3000k for bloom spectrum on white chips and 6500k for veg spectrum on white chips. You can also get COB LEDs with white chips and they are very powerful some of the best ones on the market right now, examples are all over these forums of home built LEDs using cree cxa3070 chips and getting REALLY good results.
 
AirAnt

AirAnt

Well-Known Member
if white leds are so great then why are people using monochromes at all? why does a blue white outperform and all white in veg and a red white out perform an all white in flower?

if white is the best there is then why are there other colors being used at all. quite a strange anomaly. perhaps you fine people of rollitup forums could embark on some grand crusade to educate and enlighten the world as to how wasteful we have all been using precious resources illuminating plants with anything other than white, the all-superior, all-purpose, and all purposeful hue of all. The world dwells in a darkness of ignorance inspired by the lack of true appreciation for white LEDs, and it's up to us to save it. Good luck, gentlemen, synchronize watches.
 
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churchhaze

Well-Known Member
AirAnt said:
why does a blue white outperform and all white in veg and a red white out perform an all white in flower?
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Show me proof of blue+white outperforming all white in veg please. You keep making these general claims with out any real references.

I could easily turn your fallacious question around and ask "If red+white is so good for flower,why not use a pure red light?"
 
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hyroot

hyroot

Well-Known Member
AirAnt said:
if white leds are so great then why are people using monochromes at all? why does a blue white outperform and all white in veg and a red white out perform an all white in flower?

if white is the best there is then why are there other colors being used at all. quite a strange anomaly. perhaps you fine people of rollitup forums could embark on some grand crusade to educate and enlighten the world as to how wasteful we have all been using precious resources illuminating plants with anything other than white, the all-superior, all-purpose, and all purposeful hue of all. The world dwells in a darkness of ignorance inspired by the lack of true appreciation for white LEDs, and it's up to us to save it. Good luck, gentlemen, synchronize watches.
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plants absorb more then blue and red. With monos. It causes pigments to go dormant. Not absorbing specific wave length. Green and amber are missing from monos. Green wave lengths drive photosynthesis by helping the plants to absorb more photons in other regions.. Hence the whites. Plus whites have a much higher cri than monos. The reds that are being used with whites is because those particular whites are 4500k and 6000k and are heavier on the blue side. the all white leds are best at 3000k. there's 100's of led companies that don't know anything about how plants absorb light and how light works. There's only a handful of companies that make quality led panels... the DIY white cobs are killing all other led panels and hps
 
gk skunky

gk skunky

Well-Known Member
AirAnt said:
It's not theory, it's science and common sense. 90% of usable Plant light is from like 440-460nm and 630-660nm. LED lights should therefore be 90% within those spectrums to get the maximum spectral intensity of usable plant light per watt.

If you're using white LEDs, you might as well have 300 little 3 watt HPS bulbs. Could you grow weed with that? yeah, you could. Would it be as good as lights set in the range of 90% usable plant light. Don't be freakin ridiculous.

You try it yourself. Put a white LED on one side of the plant and a blue LED on the other. I bet you all the wax in B.C. the plant leans toward the blue. I've seen it happen with different kelvins of white, plants prefer the bluer hues. Now take that same, obvious visual example of the plant showing preference for one bandwidth of light and apply it to the other end of the spectrum. Except that instead of leaning towards a bluer light, the plant will use a redder light to develop better buds and more complex cannabinoid structures.

The argument for white LEDs is ridiculous, actually.
Blue light is better for Veg, Red light is better for Flower. To say that white is superior, you'd have to be making the argument that white was better than blue for veg and red for flower and that is insane. The best the white led camp can hope for is 'white LED is better at vegging than red and flowering than blue'. As in, it's better and easier to have a non-growth stage specific light fixture through the entire growth than it is to switch from a veg lamp to flower lamp or move plants from a veg room to a flower room.

There's just no way that a white LED can match the spectral intensity output that Red and Blue LED can in the 90% usable plant light range which is 90% blue and red. Lol. I know there's some smart people in the white LED group so it wouldn't surprise me that much if I were wrong. Until then I'd rather rely on my own common sense for judgement than an opinion fostered by the operations of a government agency or it's affiliate organizations..
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Yeah All white sucks!!!! LMFAO
 

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gk skunky

gk skunky

Well-Known Member
And to answer your question why WR and WB can be "better" it's because Whites are still becoming more efficient. Reds and blues have been pretty good for a while so they help to supplement the white light to make it more biased to support veg or flower production. So you can make a white panel a little more efficient by use of the good monos. At least that is my understanding from it all.


And hey AirAnt. Don't get offended by some of our sarcasm either. Pull up a chair and stick around, you'll learn a lot.
 
L

lax123

Well-Known Member
As Nishio (2000) clearly postulated, and as we have detailed so far, red or blue light is preferentially absorbed by the chloroplasts in the upper part of the leaf. Then, when PPFD is high, the energy of these wavelengths tends to be dissipated as heat by the upper chloroplasts, while green light drives photosynthesis in the lower chloroplasts that are not light saturated (Sun et al. 1998, Nishio 2000).

http://pcp.oxfordjournals.org/content/50/4/684.full
 
ficklejester

ficklejester

Well-Known Member
hyroot said:
plants absorb more then blue and red. With monos. It causes pigments to go dormant. Not absorbing specific wave length. Green and amber are missing from monos. Green wave lengths drive photosynthesis by helping the plants to absorb more photons in other regions.. Hence the whites. Plus whites have a much higher cri than monos. The reds that are being used with whites is because those particular whites are 4500k and 6000k and are heavier on the blue side. the all white leds are best at 3000k. there's 100's of led companies that don't know anything about how plants absorb light and how light works. There's only a handful of companies that make quality led panels... the DIY white cobs are killing all other led panels and hps
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What does CRI have to do with photosynthesis?
 
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churchhaze

Well-Known Member
Exactly. Since 660nm is absorbed so well in the chloroplasts, very little of it makes it through the first layer.

Everyone talks about how they want "penetration", but they don't realize that good penetration means poor chlorophyll absorbance, by definition.

Good penetration (transmittance) is the same thing as poor absorbance.


660nm photons do not penetrate!

The poor absorbance of amber in HPS is what penetrates so well! All the red from HPS is absorbed in the top level of canopy.

lax123 said:
As Nishio (2000) clearly postulated, and as we have detailed so far, red or blue light is preferentially absorbed by the chloroplasts in the upper part of the leaf. Then, when PPFD is high, the energy of these wavelengths tends to be dissipated as heat by the upper chloroplasts, while green light drives photosynthesis in the lower chloroplasts that are not light saturated (Sun et al. 1998, Nishio 2000).

http://pcp.oxfordjournals.org/content/50/4/684.full
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hyroot

hyroot

Well-Known Member
ficklejester said:
What does CRI have to do with photosynthesis?
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Cri is color rendering index. The higher the cri the more even the spectral distribution. The more balanced or even a spectrum the more light is processed. This can be observed when leaves pray. That's a result of the stomata opening more in turn processing more light. The more even spectrum the better performance and better results. Led is 80-92 cri. Induction around 90 cri. CMH 85 - 93 cri, hps 25-35 cri.
 
hyroot

hyroot

Well-Known Member
ficklejester said:
But we know that plants do not process all wavelengths equally, so why would we give them a balance?
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so they can process all wavelengths. other wise pigments would go dormant. You want all wave lengths to be present.



Nanometers PAR Influences
200 – 280 UVC ultraviolet range; extremely toxic to plants.
280 – 315 UVB ultraviolet light; causes plants colors to fade.
315 – 380 UVA ultraviolet light; is neither harmful nor beneficial to plant growth.
380 – 400 Start of visible light spectrum. Chlorophyll Absorption begins. UV protected plastics ideally block out any light below this range.
400 – 520 This range includes violet, blue, and green bands. Peak chlorophyll absorption influences photosynthesis. Most significant in promoting vegetative growth.
520 – 610 This range includes the green, yellow, and orange bands and has little absorption by receptors.
610 – 720 This is the Red band where large instances of chlorophyll absorption occur which promote flowering and budding.
720 – 1000 There is little chlorophyll absorption in this range. Flowering and germination are influenced at the high Far-Red end as infrared heat.
1000+ Totally infrared range. All energy absorbed at this point is converted to heat.


here is some reading for you

http://www.life.illinois.edu/govindjee/photosynBook.html

http://pcp.oxfordjournals.org/content/50/4/684.abstract

http://jxb.oxfordjournals.org/content/59/15/4171.full
 
Greengenes707

Greengenes707

Well-Known Member
ficklejester said:
But we know that plants do not process all wavelengths equally, so why would we give them a balance?
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The high CRI crowd is basically trying to copy the sun...which is for all intents and purposes is a high irradiance even/flat spectrum(specially when you see it on a spectroradiometer including the atmosphere). If anything the sun's curve is shaped more like a lumen curve...which to me is the reason lumens are what they are, human vision was evolved/optimized for the sun(what allows us to see). Going further in my own theory(on how things got to where they are, not what is the perfect spectrum) that plants use what they do(McCree curve) because of their reaction/respones to the suns spectrum over time(evolution). Slightly higher in yellow, thus the plants reflect more of it to balance it out to their higher absorption colors. In the end winding up with a even use of all the light nm's...doing it through eliminated/reflection the areas of excess.
Light-spectrum.jpg
 
ficklejester

ficklejester

Well-Known Member
hyroot said:
here is some reading for you

http://www.life.illinois.edu/govindjee/photosynBook.html

http://pcp.oxfordjournals.org/content/50/4/684.abstract

http://jxb.oxfordjournals.org/content/59/15/4171.full
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I skimmed the first link there, but only found information supporting red/blue efficiency
image.jpg image.jpg

If there's a section you know supporting the contrary, please share and I'll continue reading it.

The second link is specific to green wavelengths. It states green wavelengths can penetrate chloroplasts and produce photosynthesis more efficiently than red wavelengths in bright white light, but it doesn't disclose the overall efficiency of photosynthesis without green. This study was based on the effects of green wavelengths in relation to the full spectrum and doesn't address overall efficiency compared to narrow spectrums or single wavelengths without regard to the white spectrum. The presence of other wavelengths obviously changes the behavior of individual wavelengths, but the study didn't address which is more efficient.

The third link studies non-living plants, so I don't see the correlation.

Note: I'm not trolling here. I'm all about trying new things but I want to be informed, first.
 
C

churchhaze

Well-Known Member
I think this is part of the reason people who use whites also tend to also add 660nm with their whites. It's very efficiently absorbed by the top layer, and causes %Pfr to be higher.

The new cree xp-e photo reds look pretty good, but in 1W packages, it's still very inconvenient to most DIYers on a large scale.

I would LOVE a 660nm cob from CREE, bridgelux, or phillips. I think a lot of the white users here actually do see a lot of potential in 660nm leds, it's just that it seems like 660nm and blue narrow bands alone do not do as good of a job as whites, so something is missing, and I think it's the yellow/amber.

If there was an efficient amber monochrome LED, I would consider replacing white with that.

ficklejester said:
I skimmed the first link there, but only found information supporting red/blue efficiency
View attachment 3223716 View attachment 3223717

If there's a section you know supporting the contrary, please share and I'll continue reading it.

The second link is specific to green wavelengths. It states green wavelengths can penetrate chloroplasts and produce photosynthesis more efficiently than red wavelengths in bright white light, but it doesn't disclose the overall efficiency of photosynthesis without green. This study was based on the effects of green wavelengths in relation to the full spectrum and doesn't address overall efficiency compared to narrow spectrums or single wavelengths without regard to the white spectrum. The presence of other wavelengths obviously changes the behavior of individual wavelengths, but the study didn't address which is more efficient.

The third link studies non-living plants, so I don't see the correlation.

Note: I'm not trolling here. I'm all about trying new things but I want to be informed, first.
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