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No mention of tint, only color temperature. > In my experimentation I discovered that I liked closer to 5000 in the mornings and closer to 2700 in evenings. T

No mention of tint, only color temperature. > In my experimentation I discovered that I liked closer to 5000 in the mornings and closer to 2700 in evenings. The color temperature of the sun at noon is 5000K. So at noon, you want your light to be 5000K or higher, especially outdoors (who needs auxiliary light outdoors at noon? Exactly. High color temperatures are bullshit.) But it really has more to do with eyes than the sun: the more dark adaptation your eyes currently have, the more that blue, cooler light is blinding, the more warmer light is comfortable. I don't know what it is about old timers that insist on using 6500K light even after midnight. They are literally blinding themselves and slowly doing permanent damage to their eyes. Light that cool is unnatural, and I suppose that part of the attraction, but mostly it is the mistake of believing that the brighter a light appears, the more you can see. This is completely false, of course. Beyond low light levels, brightness has absolutely nothing to do with what can be seen. The accuracy of color rendition is more important than brightness in regards to what can be seen, and the state of one's eyes is more important than brightness in regards to what can be seen. It is very possible to likely that one can see more with dark adapted eyes in the dark than with 2000Lm of 6500K light. Also not mentioned is drivers, and this is critical. Manufacturers are using the cheapest crap they can find, which means there's a lot of LED drivers out there with PWM. There is a huge rift in the lumens community about PWM, so much so that it is mostly banned from being discussed. The tl;dr is that PWM sucks and hurts some people, causes migraines, but some people don't notice PWM, and many of them are so egotistical and bereft of empathy that they don't care about anything that doesn't affect them. In order of importance, a half-decent light should have 1) No PWM, nor anything like it, instead the driver should employ constant current 2) Good tint (neutral white, like white sand... without any green or yellow cast, but a rosy cast is ok) 3) 3200K to 5200K color temperature (depends on the eyes, which depends on the time of day) and at a very distant last: 4) effective brightness

adrian_b 5y ago
The only reason why most old CRT displays were calibrated for a 6500 K color temperature was because the red phosphor had a lower efficiency than the others. Using a white with less red and more green and blue allowed the vendors to advertise a higher brightness for the displays. The same reason applied to fluorescent lamps. Choosing 6500 K allowed the vendors to advertise a higher luminous flux at a given electrical power. Nowadays there is absolutely no technical reason to use a white with the 6500 K color temperature, even if the low-quality LED lamps with a single orange phosphor still have better efficiency when emitting more bluish light, but those have a too low CRI to be an acceptable lighting solution. Nevertheless, for the lighting of my home I do not like a too yellowish white, so I use LEDs with the 4000 K color temperature, which, unfortunately, are much harder to find than those with a yellowish 2700 K or a bluish 6500 K.

adrian_b 5y ago

The only reason why most old CRT displays were calibrated for a 6500 K color temperature was because the red phosphor had a lower efficiency than the others. Using a white with less red and more green and blue allowed the vendors to advertise a higher brightness for the displays. The same reason applied to fluorescent lamps. Choosing 6500 K allowed the vendors to advertise a higher luminous flux at a given electrical power. Nowadays there is absolutely no technical reason to use a white with the 6500 K color temperature, even if the low-quality LED lamps with a single orange phosphor still have better efficiency when emitting more bluish light, but those have a too low CRI to be an acceptable lighting solution. Nevertheless, for the lighting of my home I do not like a too yellowish white, so I use LEDs with the 4000 K color temperature, which, unfortunately, are much harder to find than those with a yellowish 2700 K or a bluish 6500 K.