Redoctober
Well-Known Member
Yeah funnily enough, the 90cri 3000k has more blue AND more red than the 80cri (or at least more red in the 630-700 range). I was looking up CRI and I can't find reference illuminant spectra for anything but daylight.
"For CCTs less than 5000 K, the reference illuminants used in the CRI calculation procedure are the SPDs of blackbody radiators"
....Which is not terribly helpful.
{a small aside about CRI...}
What this means to those not familiar with CRI (someone asked about it a few pages back) is that for a given color temperature say 3000k in this example, all light sources i.e. light bulbs, LED etc, are given a value or Color Render Index for how closely they reproduce the spectral signature of a perfect blackbody radiator (object that perfectly radiates energy but absorbs none) at that particular temperature. So if just for the sake of argument, a star was burning at 3000 degrees kelvin, the LED with the CRI of 80 would be pretty similar to the light signature coming from that star, but the LED with the CRI of 90 would reproduce it even more accurately. And anything above 95 is so accurate, you'd probably need photo meters to tell the difference.
{/small aside about CRI over}
So yes I agree, I think the 3500K mixed with the 90cri 3000K would also be an intriguing experiment. I really wish to god they could have just thrown in the 3500K spectrum on that chart to make it easy.
My rationale in going with the extra 4000K blue, is this:
In the very very first grow I ever did a few years back, I ran a chemdawg clone. The only light I had at the time was a 400 watt Sun System III metal halide 4200K given to me by a friend. I didn't really know what I was doing but went straight to aero and shockingly produced a really fantastic plant. I broke all the rules of drying, I cut all the branches off immediately, I hung them in a closet where I was vegging another plant with a blue T5 exposed to light the entire time, and I probably trimmed and jarred before adequate drying had taken place.....yet....to this very day....I have never produced buds with the same smell as in that first run. When you opened the jar, it was like smelling the strongest Pine Sol ever, made from pine trees that grew on Krypton; it really was THAT strong. Stings the nostrils (like Sex Panther cologne). I have reproduced nearly every variable of that first grow with the exception of the light, in an attempt to achieve that smell but to no avail. I now realize that immediately after that grow, I switched to an HPS (cause that's what you're supposed to flower with obviously), then I went through an experimental early generation LED phase, then a T5 phase, then back to an HPS phase, now in a COB phase!
I dug that old Sun System III MH out of storage and am going to run it again, this time flanked by 5 of the 3500K COBs from the mau5-V kit. Then adjacent, I will run this new 12 COB fixture....all the same original Chemdawg strain (which is now admittedly a few years older) and see what happens. My theory, which happens to fit the facts, (as Spock would say) is that it was the MH that was responsible for that amazing result that first time, and is the reason I wanted to include the 4000K COBs.
Maybe I'll go bonkers and do 2x 12-COB fixtures one half 3500K half 3000K and the other half 4000K half 3000K.......SCIENCE!!!!!!!
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I'm growmau5. I contacted Mark over at 
