CRI 70 vs CRI 80

I notice that both Samsung and Osram are now offering white diodes with CRI 70. The Osrams came out not long ago and are described 'to increase horticulture efficiency' which is 237lm/w. Not sure what Samsungs are at CRI 70, but they are definitely more efficient than the 80's?

I was under the impression that CRI 70 were not that great for growing? Thoughts?

Low cri diodes have a lot of green phosphor in them, this is the most luminous color to our eyes. They have slightly better photon efficiency (but with low reds and yellows) but significant better lux/lumen efficiency: they are much brighter to our eyes than what they are to plants. They may make sense if youre adding in lots of reds.

Rocket Soul said:

Low cri diodes have a lot of green phosphor in them, this is the most luminous color to our eyes. They have slightly better photon efficiency (but with low reds and yellows) but significant better lux/lumen efficiency: they are much brighter to our eyes than what they are to plants. They may make sense if youre adding in lots of reds.

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Correction 234lm/w. Here is that datasheet from Osram: https://www.mouser.com/datasheet/2/588/Osram_GWQSLMS2_HM_EN-3236077.pdf

The Osram datasheet says... Photon Flux Efficacy: typ. 3.15 umol/J @ 5000K - Photon Flux: typ 0.552 umol/s @ 5000K

The LM301H EVO is 0.56 μmol/s, 3.14 μmol/J - just a cunthair more efficient in terms of photon flux.

But do the plants recognize it, I guess that is the big question? Do you by chance have any colormetrics to show too in terms of spectrum changes between cri 70 and 80? Would be interesting to find out what the deal is here as there has been way to much BS 'bro-science' that have been feeding hype on grow-lights since the inception of QB's and the whole binning/cri craze around the LM561C release.

KitnerPush said:

Correction 234lm/w. Here is that datasheet from Osram: https://www.mouser.com/datasheet/2/588/Osram_GWQSLMS2_HM_EN-3236077.pdf

The Osram datasheet says... Photon Flux Efficacy: typ. 3.15 umol/J @ 5000K - Photon Flux: typ 0.552 umol/s @ 5000K

The LM301H EVO is 0.56 μmol/s, 3.14 μmol/J - just a cunthair more efficient in terms of photon flux.

But do the plants recognize it, I guess that is the big question? Do you by chance have any colormetrics to show too in terms of spectrum changes between cri 70 and 80? Would be interesting to find out what the deal is here as there has been way to much BS 'bro-science' that have been feeding hype on grow-lights since the inception of QB's and the whole binning/cri craze around the LM561C release.

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There was a lot of discussion about this before when most used cobs and not midpower whites + reds. Also some side by side by @Rahz . I think theres a lot of info in this thread, like spectrums in different cri : https://www.rollitup.org/t/cri-test-and-mcree-weighted-results.919923/post-12928422


This pic kinda shows the overlay between a few different spectrums: basicly 70/80/90cri each have a blue peak and then a bump going thru greens yellows and reds, this bump will peak at 580/600/620-630 depending on cri. The efficiency is best with green phosphors followed close by yellow, red 630 has definite efficiency disadvantage.

The evo h has a slightly different spectrum based on blue 437nm: this light is slightly less luminous to the eye which ends up messing with the cct; warm/coldness of the light. If you check the datasheet you see it; if you compare one standard 3000k to evo h 3000k spectrum youll see that theres a slight bit more blue in the evo, which means its not really apples to apples. Youre comparing two diodes that supposed to have the same color distribution to the eye. The reality is that one needs more blue to achieve that which means you need less of phosphor to achieve the same results. Phosphors are always inherently draw back on efficiency, so the Evo h strikes a bit above this weight in efficiency in comparison.

I used to believe in high cris for higher reds and faster finishing. In our grow we had some very encouraging initial tries but over time weve seen both 80 and 90cri win to many times to be able to say whats best. Not tried 70 cri, id expect slower finishing time unless you add reds and far reds but also slightly better par /w.