So, let me shift the burden of explanation to you; please explain to me how it is that knowledge is possible WITHOUT perception, please explain to me how we can know one light is brighter than another without looking at the lights, or having to look at instruments that produce readings that indicate they are different, because that's what it seems you are arguing here. Please let me know how we can know anything at all without some way of perceiving it in the world.
I have not at any point intended to claim that knowledge is possible without perception. Rather, my point all along has been that a discussion of human perception is out of place in a thread asking what it means when an LED is marketed as Neutral. Perception originally came into the discussion when a few people posted personal opinions, not about what a "Neutral White" LED means, but about how neutral that color appears to them.
There were then several responses essentially stating that just because someone doesn't think 4500K is actually neutral, doesn't mean the name Neutral should be applied to a different color. There's a science-based definition for Neutral, and personal opinion isn't used in binning them. There's not some guy at the Cree factory whose job is to look at each LED and throw it in the Neutral pile if he likes it; the process is computerized and based on math and numbers. Just because an individual doesn't find the color particularly neutral doesn't mean it's not Neutral, because the rating is not based on any one individual's perception.
I apologize that the claim "perception isn't involved" seems to have bothered you so much. Plainly, human perception is involved in all of science at some point. However, we're not trying to redefine science in this thread, we're trying to use it to answer an incredibly simple question. Perception is no more involved in the binning and naming of LED tints than it is in the measurement of brightness. Lumens are based on human perception in the same way tint is (else we'd use mW output to describe our lights, like we do laser pointers), but we don't generally argue with the results of a test in an integrating sphere with the claim that it's all based on human perception.
Basically, I don't think we've been having the same argument. I don't technically disagree with you, I just think it's a frustrating and unhelpful approach to the question we were originally discussing.
NASA estimates that its closer to
5778K. That doesn't stop the Sun from appearing red when it sets. We do not live on the moon where there is no atmosphere to reflect, refract, diffuse and shift the color to what we experience everyday. What we experience everyday is closer to CW than it is to NW.
I'm curious whether you actually read my whole post, or looked at any of the links in it.
If you look carefully at the temperature resource I linked (also NASA), you'd see that it agrees with your figure, saying the surface temperature is about 5500°C, which is 5773K. I think the use of the word "about" in their description covers them for the missing five degrees.
I chose to round further than that because I didn't really think anyone was going to complain about the 4% margin of error, particularly since it had me listing the Sun as
cooler than it actually is, which works against my argument.
After that, I thought I'd made it very clear that yes, typical sunlight should be classified as Cool White, although not typically quite so cool as 6500K, and that even on the Moon with no atmosphere, sunlight is Cool. However, due to human physiology, the only way a flashlight should be
cooler than the Sun is if it's
brighter than the sun. Since this is generally not the case, flashlights should generally be tinted more warmly than sunlight. Sure, this won't fit 100% of humans, but I think it's a pretty good guideline - in use, for most people, Neutral tints will appear as white as sunlight, even though they're technically warmer.