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

[thedoc007]

The study was not about preference but about what light when dark adapted looked most "white".

In terms of preference under the black body ... Was the preferred color point at all CCTs in another study.

And here we go, yet another person clueless about the study making a conclusion on it. Your point is what?

Care to provide a link to the studies you are talking about? I just read the thread again, and the only reference to a specific study was to one by the "LRC". Don't know what that is...the link in the OP to a page about HID and "pure white" perception was not a study at all, as far as I can tell. And nothing was listed about the methods they used...

Maybe we are just talking about two different things...I've just been responding to what has been linked to and discussed in the thread...if you have an actual scientific study to reference, that link is long overdue.

My point is simply that you cannot assume that just because one study finds "pure white" (a nebulous term, at best) to be a certain temperature, doesn't mean that you can assume other people will agree. As many posts have already discussed, changing any of a number of parameters in the test can dramatically skew results. And given that it is a matter of opinion anyway, a study cannot PROVE something that is subjective.

If you have a reference, I would definitely be interested, perhaps it will change my mind on the matter. But just repeating yourself, and saying people are ignorant or clueless, is not really adding much to the discussion.

 

[Bullzeyebill]

Care to provide a link to the studies you are talking about? I just read the thread again, and the only reference to a specific study was to one by the "LRC". Don't know what that is...the link in the OP to a page about HID and "pure white" perception was not a study at all, as far as I can tell. And nothing was listed about the methods they used...

Maybe we are just talking about two different things...I've just been responding to what has been linked to and discussed in the thread...if you have an actual scientific study to reference, that link is long overdue.

My point is simply that you cannot assume that just because one study finds "pure white" (a nebulous term, at best) to be a certain temperature, doesn't mean that you can assume other people will agree. As many posts have already discussed, changing any of a number of parameters in the test can dramatically skew results. And given that it is a matter of opinion anyway, a study cannot PROVE something that is subjective.

If you have a reference, I would definitely be interested, perhaps it will change my mind on the matter. But just repeating yourself, and saying people are ignorant or clueless, is not really adding much to the discussion.

I concur, please keep the conversation polite.

Bill

 

[fyrstormer]

So, I just noticed this thread is 4 years old. Probably time to retire it.

 

[Bullzeyebill]

So, I just noticed this thread is 4 years old. Probably time to retire it.

No

Bill

 

[donjoe]

Or notice this: even in the early morning, before the sun rises, the skylight does a surprisingly good job of rendering wood tones, even compared to our "neutral" artificial sources! And golly, that skylight has to be 20 000 K or more! Sure the spectral power distribution is skewed heavily towards the blue. But since it's coming from a mostly-continuous-spectrum incandescent source, the deeper red is still present in significant amounts!

I would submit rather that the reds are well represented because 20 kK is well into the violet section of the spectrum, where it's nearing red again.

 

[SemiMan]

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[donjoe]

I would submit that it is probably no where near 20K CCT. That only occurs under heavily clouded skies.

I don't know about that. There's an undeniable presence of violet frequencies in the early morning twilight that's inconsistent with low color temperatures.
http://www.superhqwallpapers.com/2560x1600-high-quality-wallpapers/twilight-morning-2560x1600/

 

[Twinbee]

Wow, plenty of posts since I've been away!

Thanks Bill for not closing the thread. I doubt I could get as much insight and enthusiasm about the topic anywhere else, no matter how hard I looked, and a definitive conclusion is still somewhat out of sight.

The question "What do people consider the most 'white'?" is different than what they consider the most 'pleasant' for everyday lighting which is also a very interesting question. Perhaps someone else can start that other question.

As phrased, it is a silly question (though it has generated some interesting comments), because to know what the subjective "pure white" color is, all you have to do is some testing on your own.

I know colour 'experiencía' will differ slightly from person to person, but we can still get an average for everyone. And testing for yourself won't yield an accurate answer since people find it difficult to test for these sort of things. It's like asking how heavy a particular bag of rice is, or how many lumens a particular bulb produces. We can get close, but significant error is possible, especially if you've just exited a previous room and entered a new room with a different white where the contrast itself produces bias. The shade of wallpaper, carpet and furniture produces further bias so you have to be extremely careful.

Even if most people think it is 4300k (I haven't read the study and can't say either way) that doesn't really mean anything.

The reason why it's useful is because offices and shared spaces can set the lighting to the 'averaged' hue. Also monitor displays can use the hue as default white. It not only means something, but is extremely practical too.

For example, real colors are actually infinitely varied, and the wavelength rather than the "temperature" would be a more accurate way to describe what we CALL "color".

Well if you want to go down that route, even the spectrum won't yield the colour magenta which is a mix of red and blue.

Without going into mega-complicated 3D models of colour, a representation using RGB (red, green and blue) would suffice for 99% of people. Just a pity that monitor displays don't standardize on this, and white appears different on my laptop than my 26" monitor or 32" TV.

Lots of conjecture on this thread but the LRC did a study and found within the study group that almost without exception people picked 4000k as white +/- a few hundred k after adaptation.

Excellent - just what I wanted! Like thedoc007 said, can you give me a link?

 

[Noctiluco]

3800-4000k is very good white

 

[SemiMan]

No need for either conversation ... Both have been researched

 

[Twinbee]

Link us up then

 

[thedoc007]

No need for either conversation ... Both have been researched

If you have actual studies and research, please share it. I asked three months ago for you to provide some documentation, or even a starting place so I can look for myself. But still nothing...

 

[markr6]

I still say visit a Home Depot and look at their display for a good general idea. Keep in mind some stores may vary, but can't say for sure. They also used some CFLs, so CRI aside...

Soft White- 2700K | Bright White - 3500K | Natural Daylight - 5000K

The soft white is very close to the incandescent. I find it hard to believe anyone would argue against the 3500K being the most neutral. And there's nothing "natural" about the natural daylight 5000K in reality. Maybe in some sophisticated computer model, though.

 

[SemiMan]

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[SemiMan]

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[Twinbee]

Semiman, can you not find the study? Me and maybe thedoc will continue to bug you until you link it or at least until you give up searching for it =p

So you say it's 4000K for the the 'subjectively whitest' light right? What is it for the subjectively most pleasant white?

 

[markr6]

Can't review bulbs in a store. You eyes are adjusted to store light, not the light you will be installing. Rough idea is what you get which is better than nothing.

No I did just fine. That's like saying you can't choose a bulb inside your home since your eyes are adjusted to the sunlight, sunset, TV, glow from smartphone, etc. I guess technically you may be right, but that's splitting hairs. I looked at the bulbs in HD, and decided 3500 was the perfect temp for me. It didn't change when I got home.

It also helps they are isolated in those little boxes, not just plugged into a wall somewhere.

 

[thedoc007]

Can't review bulbs in a store. You eyes are adjusted to store light, not the light you will be installing. Rough idea is what you get which is better than nothing.

On this point I concur with SemiMan. Certainly you can get some idea...but the store lighting does give you a baseline which COULD skew your preference pretty badly, especially if you were unaware of it.

I know that if I have been using a cool source for a while, warm tints look extremely yellow. But that exact same tint can look fairly neutral white if you have been accustomed to it. That's why I think the "pure white" phrase is problematic. Depending on how you set up the experiment, you could quite easily get whatever results you want. And someone else using another method could find a very different result. Since no one is forthcoming with any actual studies, though, it may be a moot point.

 

[Twinbee]

That's why I think the "pure white" phrase is problematic.

I agree with the difficulties in removing sources of bias.

However, you can adjust for these kind of things. For example, you can stay in a dark room for an hour before seeing the light.

Bear in mind that no matter how long I stay in a room with say a 2000K or 12000K light, I'll (and I bet you) would always see a orange/red (former) and blue/violet (latter) light. Less so with 4000K and say 7000K, but still noticeable.

 

[thedoc007]

Bump. Still waiting for a link or source for ANY scientific research on the subject.