Does CRI Make a Big Difference?
- Thread starter sunny747
- Start date
Ganjineer
Member
This is really an unknown. By the traditional definition of the PAR spectrum (400-700 nm), most 90 CRI lighting will produce less photosynthetic photon flux per watt than 80 CRI. However, as CobKits stated, it is known that wavelengths over 700 nm have an effect on photosynthesis despite being outside of the traditional PAR range.
Ganjineer
Member
That would be nice, but high CRI LEDs typically have a lower luminous efficiency than their 70-80 counterparts. So you're potentially losing photosynthetic photons for the benefit of better color rendering to the human eye.
Corso312
Well-Known Member
Thank...that makes sense to use the 80 cri now..always wondered that.
mauricem00
Well-Known Member
high CRI diodes have their phosphor peak shifted toward the red giving less green but more light at 640 and 680 NM.this produces a lower lumen rating but also a lower LER so may not reflect a reduction in efficiency or radiant power.it would provide more stimulation for chlorophyll A and B.without comparison grows there is no way to know which is best. leds use indigo (450nm) to control stretching so you may need to raise the color temperature with high CRI diodes to get more 450nm light to offset the increase in deep red light
sixstring2112
Well-Known Member
without a side by side using 70 or 80 cri vs 90 or 95cri we really dont know if the benefit of more colorfull spectrum vs higher lumen makes a difference.is there a side by side like this here? i thought maybe @puffenuff did one?
DrBlaze
Well-Known Member
Any chance you could produce some par measurements, 80 cri vs 90 cri for the same series cob. I don't think I've ever seen that posted here anywhere, All we've got to go on is how many lumens each produce which is meaningless. You've got the li-cor and you stock the chips....so....
nevergoodenuf
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.
nevergoodenuf
Well-Known Member
My testing started on page 5, in my Sig is the test.
mauricem00
Well-Known Member
if radiant power is the same your photon count would go up with high CRI diodes. 1 watt of deep red light produces more photons than 1 watt of green or orange light and is more useful to plants.with all the unknown variables a comparison grow is the easiest way to determine which is best
MeGaKiLlErMaN
Well-Known Member
What was the total weight for each? Less larf is good but I'm curious what the final weights are