CRI and ANSI White bin questions

G

grouch

Well-Known Member
Greengenes707 said:
That's cool. Options are great. And sometimes if motivated enough by them to be a true believe, can actually drive new scientifically valid and accepted pricipals.
That said...your disagreement is with accepted science, not my opinion.

You also imply I said that the 80cri has nothing over 700nm. It does and is more in line with sun like and ideal to the higher CRI counterpart. As where too much is of the high CRI is devoted up there.
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I didn't imply anything about the 80cri. I think mixing both cri variations of 3000k might be my next route. I was just saying the McCree Curve isn't a hard rule. It is what the plant is most efficient at using but the plants don't disregard extra light when it doesn't match the curve exactly. Saying that higher amounts of a specific spectrum will go to waste is what I disagreed with. IMO smothering them with as much red as possible and enough blue to keep them happy might be the key (works for hps).
 
G

grouch

Well-Known Member
Would the spectrum chart found on the data sheet showing relative power be fairly accurate if comparing 80cri and 90cri if they were the same bin?
 
alesh

alesh

Well-Known Member
Greengenes707 said:
Actually the opposite.
When the McCree curve is factored into each spectrum, the 80CRI has less of a loss.
SDS has it as PER, but the more commonly known as YPF.

The high CRI "waste" it's load above 700nm. Though it is used, we all know the steep drop off at 680 to basically nothing by 740nm in the RQE(mccree) isn't contributing to the YPF very much.

Stardust is using the whole spectrum ~380-780nm so they are counted and still the higher CRI falls short in it's fitting of the RQE/mcree curve.
80cri=94,848-85,960=8888µmols÷94,848= ~9% loss to RQE
90cri=81,870-73,332=8538µmols...8538÷81,870= ~10% loss to RQE
That is just speaking spectrum potential, not counting output differences.

Output/flux is the 90% of the goal. The rest is spectrum, and when deciding between whites, leads us to 3500K giving the highest output while still hitting the somewhat accepted values of nm range ratios like blue, red, and r:fr.
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On the other hand, 3000K 90CRI has actually higher photon output than both 3000K & 3500K 80CRI (700nm+ included). It's fair to include them since they're weighted by McCree's curve.

Anyway, I made some lights for a friend with both 3000K 90CRI and 3500K 80CRI and from what he's telling, he likes 3000K 90CRI better so far.
[CXB3590]
 
SSGrower

SSGrower

Well-Known Member
grouch said:
Would the spectrum chart found on the data sheet showing relative power be fairly accurate if comparing 80cri and 90cri if they were the same bin?
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By no means am I an expert but in the CREE tech info I interpret the term "relative" to mean in relation to the total flux generated by that specific led and is not a comparison to any other led or CRI. Therefor the graph is only showing what percentage of the light's intensity is generated at a given frequency by that specific led.

I feel like CRI is like a filter and a higher CRI is a better filter but it comes with drawbacks, kind of like how a better water filter will have higher backpressure and lower flow rates unless a manufacturer makes an innovation that accommodates the better filter. I see the development of higher flux bins (AC,AD,...) as CREE's attempt at this innovation.

For my purpose I will be using only one or two(the 3000k) CXA leds from each 2700 (Y2, 80CRI), 3000(AB, 80CRI), 4000(Z2, 70CRI), or 5000(AB, 80CRI),in addition there will be 2-CXB 3000K(AB, 80CRI), 2-CXB3500(BB, 80CRI). CXBs will be driven at 36v @1.2amp and CXAs 2 in parallel on a 42V 1.5amp driver.

Your constructive criticism is appreciated especially if you have empirical data or experimental observations.
 
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Greengenes707

Greengenes707

Well-Known Member
alesh said:
On the other hand, 3000K 90CRI has actually higher photon output than both 3000K & 3500K 80CRI (700nm+ included). It's fair to include them since they're weighted by McCree's curve.

Anyway, I made some lights for a friend with both 3000K 90CRI and 3500K 80CRI and from what he's telling, he likes 3000K 90CRI better so far.
[CXB3590]
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Interesting. You'll have to get some good quantitative info from him when he is done.

If we are talking about all photons 380-780 it's...
80cri losses 13.25%
90cri losses 17.9%
to McCree

You know from the past with me I have an issue with what is consider PAR...to me and actual words of the definition... the acronym "PAR" by definition is anything that drives photosynthesis and should include all activity on the mccree curve, which is basically 320-780nm.
 
welight

welight

Well-Known Member
SSGrower said:
Understood, I really appreciate that you have the capability and willingness to do these one off requests for those of us who can't.
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no problem, Im all about the sharing, informed customers make better decisions
Cheers
Mark
 
SSGrower

SSGrower

Well-Known Member
Par - The predetermined number of strokes a scratch golfer should take to complete a hole, round, or tournament of golf. HaHa sure youve never heard that before. (insert sarcasm here)
 
G

grouch

Well-Known Member
Greengenes707 said:
Interesting. You'll have to get some good quantitative info from him when he is done.

If we are talking about all photons 380-780 it's...
80cri losses 13.25%
90cri losses 17.9%
to McCree

You know from the past with me I have an issue with what is consider PAR...to me and actual words of the definition... the acronym "PAR" by definition is anything that drives photosynthesis and should include all activity on the mccree curve, which is basically 320-780nm.
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I am having a hard time understanding what you mean by losses to the McCree Curve. Does the plant disregard these photons or just use them anyways?
 
Greengenes707

Greengenes707

Well-Known Member
grouch said:
I am having a hard time understanding what you mean by losses to the McCree Curve. Does the plant disregard these photons or just use them anyways?
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The McCree curve is the relative quantum efficiency for plants. It represents how much/efficiently light is used by photosynthesis. When the RQE/McCree curve is applied(every single nm value from the SPD, multiplied to every single value of the RQE) you get what is known as YPF or yield photon flux. Basically the lumens measurement for plants. And shows how well a SPD(spectrum) will be used by plants.


Here are the actual values of RQE

Screen Shot 2015-01-06 at 9.28.52 AM.jpg

So an example for one nm...
Ex.
1)Your SPD radiates 8mW of 452nm.
2)Now go to the RQE table and find it is .75 or 75%
3)8mW*.75=6mW would be the usable amount in the end.

That adjustment would be done to each nm SPD and the result is the YPF curve.
 
G

grouch

Well-Known Member
I understand it uses that light more efficiently but I still don't get why you call any light outside the curve a loss. Does the plant reject that light or adapt to its environment and use it?
 
V

voon

Well-Known Member
Finally, I would like to ask for your opinion and assessment on the use of high CRi .. I'm out of it somehow confused .. how ever not to reach conformity on it ..
.. However in the table PPF still have a very interesting offer higher CRi90 therefore mainly 4000K for growth .. I think 3500k 90CRi might not be a bad choice at all in combination with 3500k 80CRi .. peak at 630 nm and a high proportion of 600-680nm including FR
.. thanks
 

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SSGrower

SSGrower

Well-Known Member
I don't think any of what you listed as options are bad, I think the table you posted explains my understanding pretty well with one anomaly, the 3000k 80 cri. This one has a minnimally higher output then the comparable 70 and 90 cri. Is this because citizen has invested more in the development and production of the more "common" lamp? Why is the document stamped "confidential"?

I think you ask a legit question but I think the answer involves much more complicated philosophies on market driven consumerism and feasible production methods.
 
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