What do beam shots look like—does a blue tint dominate the beams of these two?
Depends on the lighting and tint bin. The sw45k seems fairly tightly binned and most people would say the SW45k is pink, but it is blue compared to warmer lights or at night. I have had 3 bins of the SST-20 4000k and they range from yellow-green to white-blue-pink in tint.
Interesting. Our Bundesamt für Strahlenschutz BfS gives a range of visible light up to 780nm. Is this a mean/max thing? Or don’t I understand the photopic luminosity function (likely 
)?
Question for all.
Are you willing to trade tint or color temperature for TCR?
I'm sure some people are willing to make a trade off for CRI, but "TCR" isn't a real thing. 
I’m not convinced “TCR” raises the quality of discussion. It seems more like a distraction from the subject of the thread.
Whacky, your signature grows at a frightening speed. Is there really no limit, or have you found a way around it?
There is no limit on how big a signature can be, but if it gets too big people might complain. 
I think it has found a limit. For now. :laughing:
I’ll reduce it when more and more understand and accept the reasoning behind TCR.
Yeah you have a point. Didn’t mean to distract at an expense. I’ll start my own thread on this subject. Maybe.
Don't hold your breath.
TCR will never take off because it is subjective, and not scientifically measurable.
I think you’ll be proven wrong.
PS. It’s Autumn’s thread. I’ll respectfully bow out of it.
If I was to make a guess, while those LEDs still have a significant blue spike and overall different spectral makeup than a blackbody source the difference is insignificant compared to what a lower-Ra LED or florescent would have. The latter two have HUGE gaps in the spectrum that are underrepresented vs blackbodies. Since color of an object is determined by reflected light, the slight differences in intensity of some wavelengths doesn’t matter as much for accurate color representation (since much of the light is being absorbed anyway) vs a segment/segments of the spectrum being extremely low relative the others.
About OP’s question: we do not see 450nm very well, our eyes are just 4% as sensitive to it as our peak at 555nm. So a spike at 450nm is not obvious. The blue is needed for natural colour perception, but the amount appears not very critical, although real snobs may see it.
Same for deep red, we hardly see it so it is not critical for how we perceive colours, but it does help for that last tiny bit of colour rendition.
In general: our machines detect light way better than our own detectors: our hopelessly primitive eyes. It must be noted though that we have brains that are extremely capable of squeezing every last bit of colour information out of our very poorly functioning eyes.
Lovely answer, thank you. Coming to flashlights as a bit of an objectivist audiophile, I know how controversial measurement of aesthetic machines can be. I would love to see the incandescent snobs defend their preference in a “blind” test.
I wonder if there will be any LEDs soon that fill in that last bit of red. Seems like sunlike do get rid of the blue spike.
There is another reason to not want that blue spike, not colour rendition but the influence of blue light on our mood. There is some research on that, the effect may not be huge or worrying, and the definitive facts are not out there yet, but since it is picked up by public opinion as real and dangerous, led manufacturers have no other option than respond with leds that do not have that blue peak.
Personally I have found blue blocking glasses to help me sleep and I know this is a fairly well validated fact. However for flashlights, because you can usually control the amount of light so easily, I don’t think it is as much of an issue. Also, IIRC, blue light impedes melatonin production but only if it enters the eye from above. So I drive my GF crazy by always using flashlights around the house before bedtime and turning off overhead lights.
Light level is at least as important as spectrum in regard to sleep, in real life light levels (i.e. I dim my tablet to 25% in the evening, and the house is sparingly lighted) I wonder how much those glasses add to that, and how well the “blue light effect” is researched at those levels.
Only R1 through R8 are used in the CRI Ra score. R9 through R15 were added later due to recognition that fluorescent and other lighting sources with spiky spectra were not easily compared by Ra to sources with more continuous spectra.
Hence also why you can have R9 (saturated red) scores that are effectively 0, yet score well into the 70’s for Ra.
Specifically regarding R12 being low, scroll down to TCS12 here to see a reflectance spectrum for the test swatch:
In short, blue-pumped LED’s have too narrow of a spectral peak to score get a great score here, as the test surface has significant reflectance extending into the violet range. To get a really good R12 score from an LED generally requires a violet-pumped LED like Nichia Optisolis. See here for example: Maukka’s 5000K Optisolis Measurements (source)
Fortunately, the typical LED scores in the R12 = 50 to 70 range keep the effect relatively subtle. Consider similarly how an R9 score above 50 is decent and above 70 is pretty good. Yet even before I understood the limitations of most LED’s at the blue end of the spectrum, I did notice this doing comparative photography tests of some of my first high CRI LED bulbs against some fluorescents. Although these specific CFL’s had a partially correctable color cast and had terrible rendering of greens, they actually did very well in the violet range. A vase of various colored flowers I used as a test subject showed the violet colors looking more blue and a bit dull.
Since I didn’t understand this at the time, I was confused that the high CRI bulb seemed to perform worse for shades of purple, but the improvements in the other colors compared to the CFL was far more significant.
As to the height of the spike, because most real surfaces reflect a fairly broad spectrum, we seem to not notice this. However, if you illuminated a surface with fairly narrow reflectance spectra centered on that same spike, the blue should appear exaggerated compared to when illuminated by sunlight.
As far as I know, human eye sensitivity to 700+ nm is so low that it is almost irrelevant. It should be possible to create a test scenario with extremely low reflectance until nearly 700 nm where a difference would be seen compared to sunlight, for example, but I think uncommon.