-12000-14000 K whites ? ....If they really do have that temp ,in fact they should be considered as blues ...
http://www.3drender.com/glossary/colortemp.htm
-WW indeed do have a low
lumen output ...
Photometrically ,they are of lower output of same type / tech CWs or NWs ....
Not much green light in them to appear as " bright white light " to our vision brain center ..
Plenty of their output power is at reds (when high CRI WW ) or at yellow/ambers (when low CRI WW ) ..
Plus the fact that emmit more FR/NIR than rest of whites ...Unvisible light to us ...Less lumens ....
As for actual
light radiometric power .....When talking for
thin film type of leds ...
No ,they do not differ from rest of white leds ...
In "volume emission die " type of leds ,there's a slight difference ....
No ,they are not useless for that reason ...."Useless " can be when in
low numbers ..And of the
"wrong " type ,
at same time ...
You see
,low CRI WWs ,utilise a blue die and some kind of a broadpeak yellow phosphor ....
If of
volume emission type ,
they do output lower radiometric light power than CW or NW ....
And mostly at yellow/amber ...
.Neither much blues or reds ....
If used in great numbers ,they start to show great efficiency in plant cultivation,though ....
Now ...If of High CRI (>90 ) ,then warm whites utilise mostly a red phosphor (>630 nm peak ,up to 660nm ) ,along with a green one ...And a blue die .... ( RGB .... )
If of thin film type ,also ....
Then ,those ww leds ,emmit mostly at ambers/reds/deep reds /FR at high radiometric output,as CW or NW ...
Lower still than monochromatic red leds ,but covering all red band ...Not just 'peaky' parts of it ...
And offering blue ,at "sensible " percentage / ratio with reds ,at same time ......
....Still of lower lumen output than of rest white leds ...(We can not 'sense' red wls ,as bright as we can with green wls...)
Photometric wise ,they can not exist bright WW leds(always related/compared to same tech CW & NW ...) ..
The 'warmer' they get ,the 'dimmer' they 'appear' ...
But ,they are almost as if specially made to cultivate plants ,if used even alone /solely to grow ....
More than 50-60% at red band ...~3-5% FR .....~4-5% blue (like hps have ...)....Rest is green/yellow /amber .....
..I say ,that's almost there for me .....
Maybe even a boost at 645-665 nm area will do miracles .....
I totally agree ....Except the "you don't
need green to grow marijuana" part ..
I trust otherwise ...
Not much ...But you need some ...A tad ...
To bridge the 5% ...~65% " gap " between blue & red ....
Bridge it into a smooth curve or line ....
Not much to care for this detail
...Just bridge the "power gap" of 'blue' to 'red' ,smoothly ... ...
As same smoothly goes the 'absorbance' line ,there ..... ;-P
P.S. :
I'm not after your posts or you ...
It's just that ,you oftenly ,have plenty of worthy / interesting stuff ,posted ....
Keep up the good postings ,there ..
) 
. And you'll have to excuse my atrocious use of technical jargon, in the real world I speak a very slang filled dialect and can be lazy when I'm trying to get a more technical points across. Sometimes I type a sentence 5 or 6 times and still edit it cause I feel I'm not getting across my idea across properly. But I will be "digesting" your words soon.
