25% more yield with a diffused LED ?

[Cerathule]

The spots are due to varying angles when leaves allow a small corridor of light to shine through.
It's typical for LEDs setups that use different colours and esp. mid-powered diodes. The only way to not have these is to use a single white diode for all. It's not really pronounced here but there are other lamps like Greenception4 that give a funny mosaic colour to walls or the floor once the tent fills up in veg

 

[Ca++]

Good pics. Nice.
It looks like I was editing as you were typing.
This shows how the red could actually gain over the white as distance increases. Based on being right in the reds beam. However... I have seen these dots off at 45 degrees. It's still not quite the right picture.

I wonder if we see them, as there is just so much red. Red from the whites is high. Then we might be adding 10% more. Just maybe, like plants, are eyes are particularly receptive to 660nm. I can't speak for the biology behind either. Still.. it's dots

 

[Cerathule]

No eyes are either most receptive to 550nm or 500nm but 660 is already way outside and around only 15-1% of the max depending on whether it's day or night

 

[Ca++]

The spots are due to varying angles when leaves allow a small corridor of light to shine through.
It's typical for LEDs setups that use different colours and esp. mid-powered diodes. The only way to not have these is to use a single white diode for all. It's not really pronounced here but there are other lamps like Greenception4 that give a funny mosaic colour to walls or the floor once the tent fills up in veg

Yes, shuttering has been the best explanation yet. Though the suggestion came with reason why it might not be so. Also, that this shuttering causes areas on the plant to have this excess red spotting which is shown to have a negative effect. Lowering yield beside the control

 

[Ca++]

No eyes are either most receptive to 550nm or 500nm but 660 is already way outside and around only 15-1% of the max depending on whether it's day or night

Yes, green. Slap bang in the middle. We see more shades of green than any other colour. I'm open to the idea of other spot frequencies exciting certain receptors though

 

[Cerathule]

Under a GC4 white COB + midpower monos

it's at max hanging height

Royal Blue monos at close range, even the presence of 2 HIDs can't help to give any "dillution"

 

[Ca++]

Looks nice with the blue on it, but such ratio's have also been shown to be unhealthy.
If your light units are quite separate, such as some cobs with auxiliary lighting, it's somewhat more expected. Two lights in different places.
With something like a QB, it becomes less likely, but still happening.

I must resist using my eyesight to consider what a plant might see. We obviously pick out different colours quite well, but only by our own standards. Some animals only see in black and white it's (perhaps wrongly) said. While we see white as different colour temperatures with which we have seen plants respond. These 40 60 80% red ratios plants have been tested with, are certainly not missed by us. We see blue to red, as oddly they do. It's not dissimilar. However they like blue and red, and we like green.
We can see what a lot of red or blue looks like though, in terms of what a plant also feels about it. Our plants like different colour temperatures of white, like we do. Not red or blue painted leaves. I bet a diffuse cover would solve this colour spotting we know isn't wanted. What we need to weigh, is just how bad these poor ratio's really are. In terms of actual damage being done. Find light that we don't actually want. Which isn't an issue of the colours in use, but rather, good colours can be used in ratio's that have a negative effect. Not poor. But actually subtracting from our goals.

papers on blue and red from different studies both said 40% and when we think about them studies, it's based on blue green and red. Where the sun would be giving each a 33% share. So 40% is not that big a difference in white balance, before things go bad.


I started off thinking this diffuser idea was just lost light, so bad. The more I think about it, lost light isn't always a bad thing.

 

[sshz]

Interesting that the Gavita 1650e Pro LED (older model) came with diffusers over the diodes but Gavita removed them from the latest 1700e LED Pro's............ there was a reason but I can't seem to find it now.

 

[Three Berries]

I use to do side lighting. Each plant got two sides and turned 90* once a day. Had a dual T5 and two 50 w square COBs.

 

[Ca++]

I use to do side lighting. Each plant got two sides and turned 90* once a day. Had a dual T5 and two 50 w square COBs.

I like side lighting. Many people will fit some that's not as strong as the main lighting. This will fill up the plants with stuff you don't want. Often people trim the bottoms off in early bloom, so any side lighting before this time is growing stuff to chuck. The better use of side lighting is to use it after stretch, and training/trimming is done. At this time the bud sites are set, and any extra light, however weak, just adds to the bud sites in situ. This way an e27 domestic lamp won't grow an extra bud to chuck away. It will instead help a bud that's going to be there regardless.
I actually don't sidelight. I put lights on the floor. Illuminating the bottom of the main canopy. Something like 400ppfd. The growth pattern is like the top lights got deeper penetration. Then you realise.. no rubbish to chuck either.
Running such lighting in veg is totally pointless for most grows. It's just a load more at the bottom to remove. Millions of cuttings you didn't need.
I think auxillary lighting hasn't caught on because of this basic misuse.

 

[Three Berries]

TALF is underrated.

 

[GMT]

The radiation pattern for the red diodes in question is narrow?

Working Principle of LED - The Engineering Knowledge

In today’s tutorial, we will have a look at Working Principle of LED. The full form of led is a light-emitting diode it is a diode that emits light when

www.theengineeringknowledge.com

Does that suggest the inverse square law doesn't apply to red LEDs?

 

[goingrey]

Does that suggest the inverse square law doesn't apply to red LEDs?

It suggests that a narrow beam LED (of any color) spreads out less.

 

[Cerathule]

Does that suggest the inverse square law doesn't apply to red LEDs?

Exactly. The Inverse-Square-Law can only be applied if you have a point-source, where the light emanates from in all directions, like a sphere.

 

[FranJan]

https://www.sciencedirect.com/topics/engineering/inverse-square-law

​

LED advancements for plant-factory artificial lighting​

Cary A. Mitchell, Fatemeh Sheibani, in Plant Factory (Second Edition), 2020

10.18 Distribution of light from LEDs​

In isolation, an LED is a point source of radiation that obeys the inverse square law (Bickford and Dunn, 1972), which explains why radiation from an individual LED declines exponentially with increasing separation distance between the photon-emitting surface (LED chip) and a photon-absorbing surface (leaf). However, the combination of emission angle from LEDs determined by the lens surrounding each chip (typically 120–150 degrees) plus the designed spacing among LEDs on an array together determine the degree of photon-beam overlap designed to provide a coherent beam of light from a given planar fixture to irradiate a given cropping area. The combination of primary optic lens surrounding each diode plus LED spacing on an array lessens the loss of beam intensity from an array with increasing separation distance compared to isolated, individual LEDs. Fixture beam intensity still declines with distance in a nonlinear fashion, but less than for widely spaced point sources. One cost of overlapping light beams from individual LEDs in an array includes beam spreading beyond the boundaries of the fixture and a drop-off of irradiance at its edges, which causes a certain loss of photons (Cocetta et al., 2017) unless multiple fixtures are then spaced for overlapping array beams over a growth area. That is a common supplemental lighting strategy for large growth areas in greenhouses, but in PFAL with long, narrow shelves on multiple tiers, spillover and reflection of photons into aisles and off of warehouse walls decreases the efficiency of lighting and wastes electricity for SSL. Secondary optics can be fitted over LEDs to reshape beams and reduce such edge effects, but at the cost of LED photon efficacy (Lee et al., 2013). Additional research is required to determine tradeoffs between loss of LED efficiency associated with beam reshaping/collimation versus loss of radiation beyond boundaries of the growth area.

 

[Cerathule]

How much radiant power will a laser diode's beam loose with the distance when the photons travel in an ideal vaccuum?

 

[FranJan]

^^^
With or without coconuts?

To quote:
"In a perfect laser beam the 1r2 law would not hold. The beam diameter would not change, you would have the same energy density at any point on along the beam. HOWEVER. Perfect laser beams do not exist. Every real laser has a bit of beam divergence. If the beam is divergent, then at a significantly large distance you would measure a drop off in energy density according to 1r2."

Reference: https://www.physicsforums.com/threads/inverse-square-law-and-lasers.177187/

 

[Cerathule]

^^^
With or without coconuts?

To quote:
"In a perfect laser beam the 1r2 law would not hold. The beam diameter would not change, you would have the same energy density at any point on along the beam. HOWEVER. Perfect laser beams do not exist. Every real laser has a bit of beam divergence. If the beam is divergent, then at a significantly large distance you would measure a drop off in energy density according to 1r2."

Reference: https://www.physicsforums.com/threads/inverse-square-law-and-lasers.177187/

I think the poster #8 is actually right.

Because, when you measure it (even a cheap laser like from a laserpen diode just over a small distance, even in our atmosphere) you get nowhere the diminishing of irradiance as "1/r^2" puts it.

This formulae calculates that after 2m distance the laser should be only of 1/4th irradiance than compared to 1m distance.

 

[Ca++]

The rule is big bang like stuff. Where everything comes from the middle, heading out equally in all directions, in straight lines.

While everything is on the same heading, moving outwards, the rate at which the matter thins out is described mathematically as such "1+1 makes 2"

There are presumptions involved, to make the math so simple. We have a single point everything comes from, and an equal radiation in all directions.

Once we start taking our evenly emitted light, and bending it off in other directions, or having light from other directions joining ours, these need adding to the math in order to get the right answer. Our math is just about that point source emission in all directions. Even spread for everything,

We have the big bang law, but the laser also has gravitational lensing. Forces used to reduce the lights diversion angle, outside that of sphere-like radiation patterns (r?2)


As a side note, we can bend light a lot. The crt tv fired coloured light from the back, and used charged deflectors to bend the beam, so it fell on just the right part of the screen. When you think about the 3 colours, and the refresh rates, it's no small task. Kinda makes the job of an LED tv look dull. Non of the drama. That high pitched climbing scream from the high voltage transformers coming online, like a space ship powering for warp. Then the drop out, as you switch off, and all the mass of light collapsed into a central glow. That was entertainment taken for granted.

 

[Koondense]

Not so fast
It's off topic but the crt tvs or monitors didn't fire photons and deflect them. It fired electrons which excited the screen and the screen emitted photons. Electrons have a charge which makes them react to magnetic and electric fields,light is inert to it as photons don't have charge.
Second...inverse square law simplified. It tells you how to spread anything over a surface. Lasers beam don't change surface with distance so the law does not apply here. A laser beam intensity is constant if not disturbed.

Cheers