Does CRI Make a Big Difference?

Hybridway

Well-Known Member
I have done a side by side with 4000k 80 vs. 3200k 95+ CRI and the high CRI produced less larf. This was less than a 5% difference in weight and less than 1% difference in THC test. I think the extra stretch helped the high CRI. The lux meter shows that the high CRI is 10% less, but the plants said something else.
How'd you get 95+ CRI chip? Or dod you supplement w/ monos? I'll head over to see. You got the sick DIY HO lights if I remember correctly.
 

DrBlaze

Well-Known Member
It did slightly better for being less lux.
I applaud you for the work that you went to detailing this side-by-side. The only thing is, I have no way of knowing if the differences in the 2 sides were due to color temperature or cri. I suspect that the color temp may have had more to do with the slight difference in how the plants grew (much more blue), moreso than the cri, but that is just a guess.

While the lower cri cobs will always beat the higher cri cobs on a lumen meter, since they have more of their energy at 550nm, I suspect that the overall par readings of the 2 are probably close. But until someone like @CobKits, or his Clark Kent-like friend @BOBBY_G, does a par comparison between 2 chips of the same color temp (high and low cri), we can only speculate.
 

MeGaKiLlErMaN

Well-Known Member
I applaud you for the work that you went to detailing this side-by-side. The only thing is, I have no way of knowing if the differences in the 2 sides were due to color temperature or cri. I suspect that the color temp may have had more to do with the slight difference in how the plants grew (much more blue), moreso than the cri, but that is just a guess.

While the lower cri cobs will always beat the higher cri cobs on a lumen meter, since they have more of their energy at 550nm, I suspect that the overall par readings of the 2 are probably close. But until someone like @CobKits, or his Clark Kent-like friend @BOBBY_G, does a par comparison between 2 chips of the same color temp (high and low cri), we can only speculate.
Check out the DIY led calculator, the par reading are there, not for all and it's not a spectral analysis but still
 

DrBlaze

Well-Known Member
Check out the DIY led calculator, the par reading are there, not for all and it's not a spectral analysis but still
But are those par numbers the result of measurements of cobs of various color temperatures and cri, or did the person who built the spreadsheet just take the lumen numbers supplied by the manufacturer and apply the standard led adjustment (which does not take account the spectrum, color temperature, or cri but is just an approximate average of all led lights), in order to get a guestimate of par for their par/w calculations? If the latter is the case, then the par numbers in the spreadsheet would be exactly as useful as the lumen numbers for comparing cobs of differing temperatures and cri..
 

Ganjineer

Member
It is a really interesting question. We obviously need to see more real world grows. I applaud @nevergoodenuf for being on the cutting edge!

I have a feeling that we will start to see more people supplementing their "normal" 80CRI lighting with low temperature 90+ CRI lighting, in a similar manner to how we see people supplementing with 660nm monos. I believe @Nenno44 has already done this.
 

DrBlaze

Well-Known Member
I applaud you for the work that you went to detailing this side-by-side. The only thing is, I have no way of knowing if the differences in the 2 sides were due to color temperature or cri. I suspect that the color temp may have had more to do with the slight difference in how the plants grew (much more blue), moreso than the cri, but that is just a guess.

While the lower cri cobs will always beat the higher cri cobs on a lumen meter, since they have more of their energy at 550nm, I suspect that the overall par readings of the 2 are probably close. But until someone like @CobKits, or his Clark Kent-like friend @BOBBY_G, does a par comparison between 2 chips of the same color temp (high and low cri), we can only speculate.
OK, I guess I'm behind the times. Rahz took a bunch of par readings comparing different temperatures and 70-80-90 cri for the 1825 in this thread which i somehow missed:

https://www.rollitup.org/t/cri-test-and-mcree-weighted-results.919923/

What's nice is that he also weights the measurements with Mcree to give us a bit more to consider
 

CobKits

Well-Known Member
I have done a side by side with 4000k 80 vs. 3200k 95+ CRI and the high CRI produced less larf. This was less than a 5% difference in weight and less than 1% difference in THC test. I think the extra stretch helped the high CRI. The lux meter shows that the high CRI is 10% less, but the plants said something else.
lux meters are pretty biased to visible spectrum centered around green
 

Rayne

Well-Known Member
With utter disregard for the needs of human eyes(IE: Luminous flux, luminous effeciency, lumens per watt, etc).

Within a grow space that is about 3 square feet.

In addition to supplementary ultra violet B and ultra violet A radiation.
For vegetative growth related purposes, since there is more blue. I am using 6500k 80CRI
For flowering growth related purposes, since there is more red. I am using 3500K 90CRI

Also keep in mind... HPS/MH has a cri rating of maybe in the middle twenties. Relative to the output of HPS/MH... Yes. Higher CRI, whether 80 or 90+, will make a difference.
 
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HalfBee

Well-Known Member
I took the lower lumen output of the 90 CRI and it's additional red and put it between two 80 CRI,
seeing if it would mellow out the 'hot spot' in the center of grow space, still testing...

Only have one plant centered at the moment and it's rotated 1/4 turn daily. (not really testing is it...)
They had 80 and 90 in stock for same price so mix & match - possibly the opposite combo double 90 and 80 in center.
OP - does it make a difference? A: Not to me, I use what I have and can afford but am satisfied BEEing a bit different...
 
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