What colour temperature is subjectively closest to "pure white"?

[Lawliet]

They are about half black body radiation, half a blend of red, green and blue spectral lines that get smeared because of the high pressure/temperature.

I haven't seen CRI measurements, but the only time someone makes a fuss about lighting selection is when some pigments are UV active. Thats from people who complain if you use incans of different age in one lighting setup.

[Kinnza]

The problem with this question is each person has a different expectation about what "true white" should be. So the first consensus about it is that there is no universal "true white", neither from an objective of subjective viewpoint.

Color perception varies from person to person, although fortunately it follows some universal paths. But the main complication is color is a multi dimensional concept. Should be "true white" about hue? In this case, a pure white should fall on the planckian locus or very close to it, say no more than 3 step McAdam ellipse and preferably, for definition, into a 1 step one (Duv<0,0007) so no any hue ("tint") is noticeable. I think in this point most people agrees. And between 3500 and 7000K.

But color has many more dimensions, and agreeing which of them is more important is way more subjective. It depends of personal preference and somewhat on the culture you have grown in. Should "true white" render colors as more similar as possible as sunlight? If so, what sunlight phase? Morning, noon, afternoon? Cloudy or clear sky? In general, most consensus along the color scientific community has been to choose sunlight like light sources, the most prominent the Illuminant D65, in which is based CIELAB, the main official (CIE) color space. But many people feels 6507K as too "cold".

It seems most people favor other dimension of color and light: its effect on our mood. Almost perfect white sources, as D65, but with a high percentage of blue white may be perfect for many people on a working space or when they want a feeling of cleanliness, but too "active" for a living room, where people prefer warmer tones so they feel more relaxed.

Another dimension of lighting is the level of light itself. This parameter is often overlooked, but it is very important. A same color of light has different effect on our mood and render colors differently as luminance level varies. Although our brain usually compensates for changes and contrast when luminance varies, it is not the same a D50 at 5 cd/m2 than at 100 cd/m2. Actually, I think many people that identifies incandescent lamps as the most pleasant white would be surprised if tries a colder tone, as 4500K but at lower luminance.

Should "true white" be pleasant or reliable on color rendering? I think the point most difficult to reach a consensus is this. Should it make scenes appear "natural" (whatever it means) or vivid, with enhanced color?

In my personal preference, I think a true white is somewhere between 4000 and 5000K, very close to planckian locus and providing a luminance matched to each application.

[smarkum]

Reviving a sleepy thread. . . this caught my interest as I spend 8-10 hours a day in an office lit by 3 lamps. Initially I just put the reg. bulbs in there that were "full spectrum" 40 or 60 watt. The result was flickering . . . I work in a big office buliding so checking for the power flow to the outlets is out. So, I then tried those low watt cfl bulbs that were rated "warm". The flickering was much better , but still there. I'm VERY aware of such flickerings, a sad thing for sure! Finally I have in there two LED bulbs that use 6 watts or something like that. I'm at home now, so I cannot confim what temp the bulbs are , but I know they are warm. My goal in my office was to create warm ambiance. . . and soft lighting. I did accomplish the soft lighting part, but after reading this thread, I think I've gone overboard on the warmth scale. And, I do get headaches nearly everyday at work (I thought it was due to the nature of my work). And, I find that at certain times it seems as though the room is "foggy". I know that probably doesn't make sense, but that is how it seems by the end of the day and when my eyes and ears are REALLY tired. So I think I will get some bulbs today that are in the 4500 - 5500 range and see what diff. that makes. This has been an expensive experiment. And, considering the LED are the way I must go for less flickering, it will be even more expensive after the new bulb purchase. If anyone has any thoughts on my approach, I'd love to hear them. And, thanks for this most informative thread!

[fyrstormer]

Use a halogen desk lamp. The rest of the office can be lit by flickery fluorescent bulbs and it won't matter as long as the light near your workspace is steady.

[smarkum]

good info to have . . . thanks fyrstormer!