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

  1. #31

    Default Re: What colour temperature is subjectively closest to "pure white"?

    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.

  2. #32
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    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.

  3. #33
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    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!
    "I always prefer to believe the best of everybody it saves so much time." - Rudyard Kipling

  4. #34
    *Flashaholic* fyrstormer's Avatar
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    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.

  5. #35
    Flashaholic* smarkum's Avatar
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    good info to have . . . thanks fyrstormer!
    "I always prefer to believe the best of everybody it saves so much time." - Rudyard Kipling

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    Default Re: What colour temperature is subjectively "pure white"?

    Quote Originally Posted by ElectronGuru View Post
    My testing shows 4300K to be the mark, but 4200-4600 is close enough in most applications. 5000K is still pretty blue. 3000K is quite yellow.

    One of the issues is that this scale is designed from the use of a single technology (glowing hot metal). So a non-glowing-metal source (LEDs for example) can be (measure at exactly) 4300K and still be tinted with a color not on the color temp scale, like green.
    I agree with you because the question in the thread's title says: "subjectively".

    And by the other hand we must to remember that "daylight" in really fact means a narrow but variety range of tone colors: at the morning tends a bit to blue; and in the evenings turns a bit to the yellow.

    But the word is: "pure white" I am waiting for the arrival of some cfl's; then I will test for myself; some facts about some labels in the lamps.

  7. #37

    Default Re: What colour temperature is subjectively "pure white"?

    What really confuses me is that the 4100K T8 fluorescents in my home closets are nice and white, (but I would say too cool for living spaces). But my Zebralight neutrals 4200K and 4400K lights are completely different. If my closet lights are really 4100K, the zebralights have to be below 3000K. I couldn't imagine the tolerance to be so high.

    My Fenix PD32UE torches are also very close to pure white, I'm guessing 5000K. But still a little bluish.

    L10s w/ Nichia 219, PURE white (high CRI or not)
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  8. #38

    Default Re: What colour temperature is subjectively "pure white"?

    Quote Originally Posted by markr6 View Post
    What really confuses me is that the 4100K T8 fluorescents...
    The problem is the scale itself. Color temp is linear, 1 dimension like a long thin road. Designed to measure incan sources, its like stating your location in a small town based solely on how far along a central railroad track you are standing.

    Modern light sources are 2 dimensional, having multiple colors and other variations. A given LED or fluorescent light source can be so far away from that center, as to be meaningless. They K value is simply how close you can get to actual, on that railroad track. Distance from the track is completely ignored.

  9. #39

    Default Re: What colour temperature is subjectively "pure white"?

    Quote Originally Posted by ElectronGuru View Post
    The problem is the scale itself. Color temp is linear, 1 dimension like a long thin road. Designed to measure incan sources, its like stating your location in a small town based solely on how far along a central railroad track you are standing.

    Modern light sources are 2 dimensional, having multiple colors and other variations. A given LED or fluorescent light source can be so far away from that center, as to be meaningless. They K value is simply how close you can get to actual, on that railroad track. Distance from the track is completely ignored.
    Got it...thanks!
    GOOD TINT!

  10. #40
    *Flashaholic* fyrstormer's Avatar
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    Default Re: What colour temperature is subjectively "pure white"?

    The distance away from the actual blackbody radiation line-graph isn't ignored, it's expressed as Color Rendering Index. 100% CRI means the light contains the exact radiation spectrum indicated by the color-temperature it is associated with. I don't know if 0% CRI exists, but I suppose it would mean the light has the same tint as the color-temperature it's associated with, but it's all the way at the edge of the visible-color gamut, far away from the blackbody radiation line-graph.

    One example would be cyan light, which is a single color, but it *could* be labeled as 40000K with 0% CRI -- at a casual glance the overall tint of the light source might look the same, but the cyan light would be completely incapable of rendering any colors except cyan, unlike true 40000K light, which can render all visible colors, albeit with a strong bluish tint.

    On the other hand, a deep red light would also be single-color, but could be labeled as 1000K with 100% CRI. That's because the dimmest blackbody radiation that people can see only consists of a narrow range of deep red light, mixed with a bunch of infra-red that we can't see, so a single-color deep red light would have the same rendering capability as true 1000K light.

    If there's a problem with using blackbody radiation to rate the quality of light, it's mostly that people don't actually know what makes good light anyway, so they use hot glowing things as a benchmark, because they can instinctively relate to it.
    Last edited by fyrstormer; 02-26-2014 at 11:44 PM.

  11. #41

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    Default Re: What colour temperature is subjectively "pure white"?

    Subjectively, I much prefer cooler tints. Anything below 5000k looks off to me...a white sheet of paper doesn't look white any more, it is that simple. I don't care how it "feels", I just want white to look white. 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. No one else can tell you what your preference will be, or what color temperature you will perceive as "pure white". For me, 5500-6500k is ideal. I originally bought into the idea that it wasn't good for home lighting, but after buying several different color bulbs, and trying them out, I have changed my mind. My ideal setup is similar to how saabluster designed the Rev Captor...a couple bright 6500k bulbs, and one dimmer 3700k bulb to boost the CRI.

  12. #42
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    There is no "color" label that is actually meaningful other than as a range.

    What we CALL red, or blue or green, etc, is simply a concept, not an exact value.

    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".

    There are a range of wavelengths that we might consider to be be "red" for example. Which is the "real red"?

    They ALL are, but, based upon our societal influences, each of us will CONSIDER a particular wavelength RANGE to be "the most red", etc.


    For example, we might look at a color, and describe it as sort of a yellowish green. Why do we not have a NAME for that color, the way we have for yellow, or green? Its because we just happened to name only a few colors, and could have just as easily labelled yellowish green as yellow, or green, or blue, or ishcabible, etc.

    In Greek times for example, violet was how they described some people's hair, as they had fewer names for colors, so, black hair was called violet. This makes sense, as when you look at a color chart, violet DOES tail off to what we might call black....but they didn't have black as a color label yet...it was violet. IE: Black was violet. If we asked "what's the "true violet", what would they have said? The color of a Greek maiden's hair?







    We have arbitrarily labeled part of the spectrum as being "a color". We even talk about "how many colors" are in a rainbow, etc. ALL the colors are in a rainbow, but, we artificially made up "break points" that divide the infinite number of colors into groups.

    These groups do not actually exist in any physical sense of the word, other than by human consensus...and, different groups of humans have broken them down differently, so there are "colors" that people from different regions, etc, can argue about.....but, its all about the labels they each ascribed to parts of the spectrum.

    To FURTHER attempt to use a color TEMPERATURE scale to describe a COLOR is going to be even more vague, as its not really about color as much as about the color at a particular time of the day for instance.


    IE: There is no "color temperature" that = "pure white".

    Last edited by TEEJ; 08-29-2014 at 05:52 AM.

  13. #43

    Default Re: What colour temperature is subjectively "pure white"?

    I like the displays at home depot. I think they use CFLs which I don't use, but still gives you a good general idea.


    GOOD TINT!

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    Default Re: What colour temperature is subjectively closest to "pure white"?

    Quote Originally Posted by Twinbee View Post
    Yes, but that's just the sensory contrast of going from one situation to another. If you stick in one enviroment, then there should be a colour temperature that's closest to what most people would consider pure white (as you imply yourself afterwards).
    Millennia of experience deny a constant environment. Sunlight ranges from 3000 to 7000K CCT, depending on conditions (Sunset, overcast, noonday, etc). You're looking for something that's not possible.

    Look for a light source between 3000K and 5000K (Higher CCT for work-like tasks, lower for relaxing tasks), with good color perception card results. R9 is a weak point for LEDs and arc lamps - It's a delicious red. The blues are weak for hot filaments.
    My biggest light-hog is my camera.

  15. #45

    Default Re: What colour temperature is subjectively closest to "pure white"?

    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.

  16. #46

    Default Re: What colour temperature is subjectively closest to "pure white"?

    I did my own study and found it to be 4300, within the range above:

    http://www.candlepowerforums.com/vb/...olor-Reference

  17. #47
    *Flashaholic* fyrstormer's Avatar
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    4300K is significantly warmer than pure white to my eyes. 6000K is pure white to me, but I prefer 5000K because I like just a teensy bit more yellow in my light.

  18. #48

    Default Re: What colour temperature is subjectively closest to "pure white"?

    Quote Originally Posted by fyrstormer View Post
    4300K is significantly warmer than pure white to my eyes. 6000K is pure white to me, but I prefer 5000K because I like just a teensy bit more yellow in my light.
    That's my preference as well. I don't enjoy brownish yellow light. Some people clearly do. Ideally you want a complete spectrum but led's cannot do that as I understand it. One thing I know. I find greenish light intolerable but I'm told some hunters prefer it.

  19. #49

    Default Re: What colour temperature is subjectively closest to "pure white"?

    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.

  20. #50

    Default Re: What colour temperature is subjectively closest to "pure white"?

    Quote Originally Posted by fyrstormer View Post
    4300K is significantly warmer than pure white to my eyes. 6000K is pure white to me, but I prefer 5000K because I like just a teensy bit more yellow in my light.
    Can't believe what I'm hearing?!?! It's amazing how different everyone is on this subject. Also can't believe peoples eyes can be so different from another.

    But consider just my own eyes. When look out of just my left eye, it's like looking thru a warming filter. Just my right eye is like cooling filter. Very strange. This is more apparent when outside looking at landscapes, trees, sky, the road, etc. The difference is even more exaggeated with sunglasses on.
    GOOD TINT!

  21. #51
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    [QUOTE=markr6;4502When look out of just my left eye, it's like looking thru a warming filter. Just my right eye is like cooling filter. [/QUOTE]

    Have you considered a cataract issue with one eye? I recently had cataract surgery on L eye, and now everything is brighter.

    Bill

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    *Flashaholic* fyrstormer's Avatar
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    Quote Originally Posted by markr6 View Post
    Can't believe what I'm hearing?!?! It's amazing how different everyone is on this subject. Also can't believe peoples eyes can be so different from another.

    But consider just my own eyes. When look out of just my left eye, it's like looking thru a warming filter. Just my right eye is like cooling filter. Very strange. This is more apparent when outside looking at landscapes, trees, sky, the road, etc. The difference is even more exaggeated with sunglasses on.
    Oh, but they are. Everyone's retinas have different densities of red, green, and blue cones, and everyone's brains are more or less sensitive to inputs on those three channels. Some women have four-color vision, too, because they have two types of green cones, each one coded-for on one of their two X chromosomes.

  23. #53

    Default Re: What colour temperature is subjectively closest to "pure white"?

    Yet anytime testing is done except for the obvious outliers most people test surprisingly similar.

  24. #54

    Default Re: What colour temperature is subjectively closest to "pure white"?

    Quote Originally Posted by Bullzeyebill View Post
    Have you considered a cataract issue with one eye? I recently had cataract surgery on L eye, and now everything is brighter.

    Bill
    No, but I did have a thorough exam just 2 weeks ago and everything was fine. I vaguely remember doing the standard test optomologists do when I was a kid, looking thru a book with "hidden" numbers in various colors. I think he said there was a very slight issue distinguishing certain colors, but haven't had a problem. Could have something to do with color temperatures...who knows.
    GOOD TINT!

  25. #55
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    Default Re: What colour temperature is subjectively "pure white"?

    Thanks to felixnauta for bringing this thread to the present.

    The word 'subjective' allows some flexibility here. I used to consider the white-is-white standard to be the be-all-end-all of tint preference. Now I use another subjective metric:

    Going outside when the light of the sun has the most pleasing cast (for me it is about 1/2 to 1 1/2 hours after sunrise) and finding an area of exposed dirt on the ground that is in partial shade (but one can also use the shadow made from your body). Now, shine your lights on the shadowed part of the dirt near dirt that is lit by the sun. Green plants and other objects don't look quite so 'off' as the medium brown dirt we have here, under the light of a flashlight.

    Cool white looks washed out and dull. Warm white and 'neutral' XML2's look yellow. The SkyLumen SL-1 XML2 dedomed neutral looks kind of bluish green. The ZebraLight SC62d is close to the sun's tint but a little grey with maybe a tiny smidge of green. What looks the closest to early morning sun? For me it is the MBI HF Nichia 219A.

    At night, it is the dirt around where I live that is the most distractingly off color under the light of a flashlight, and the Nichia makes the dirt look darker and 'richer'. But the sunlight test really shows how nice the Nichia is. I'm wondering how the 219B ~5000K looks?

  26. #56

    Default Re: What colour temperature is subjectively "pure white"?

    Quote Originally Posted by KITROBASKIN View Post
    I'm wondering how the 219B ~5000K looks?
    I like the 219B in my L10C. It's on the cool side though. While I think it makes colors more accurate, I prefer the warmness (slight red tint) of the 219A. And I would say the 218B is pretty close to the SC62d.
    GOOD TINT!

  27. #57
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    Default Re: What colour temperature is subjectively closest to "pure white"?

    Quote Originally Posted by SemiMan View Post
    Yet anytime testing is done except for the obvious outliers most people test surprisingly similar.
    If you really believe that, you need to look up the definition of "confirmation bias". Even scientists are susceptible to it, but when common people like us get our hands on the data, confirmation bias basically bulldozes anything resembling an accurate interpretation of the data. I don't know how many times I've seen someone start a thread on CPF about an article that "proves" their own personal preference is the default for humanity, whether it's warm-tinted white light or red night-vision light or whatever. The arguments ALWAYS go something like this: "I just read an article stating that humans are 'programmed'/'adapted'/'designed' to prefer a certain type of light. Don't argue with me, it's totally true! Look, I have numbers! Do you have numbers? No? Well, that proves my preference is based on fact and other people's preferences are based on opinions." Arguments like that aren't even logical enough to be wrong.

    Thank you and goodnight.
    Last edited by fyrstormer; 09-03-2014 at 03:03 PM.

  28. #58

    Default Re: What colour temperature is subjectively closest to "pure white"?

    Scientific studies can only result in confirmation bias if the outcome is one that is generally known or accepted. That absolutely is not the case in this study.

    People also like to keep believing what they believe even proven not true.

    The study was not about what color you like it was is this color white. If not , how do you think it differs from white. Given that people would not even know what CCT they were being shown how could they have confirmation bias? Without relative comparison or references it hard to pick CCT ... You just know whether it looks sort of reddish yellow, too bluish, or WHITE ... Exactly what the study was trying to figure out .. Where was that point.


    Of course another thing that happens is people bash studies or jump on the study bandwagon without reading them and understanding them.

  29. #59

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    Default Re: What colour temperature is subjectively closest to "pure white"?

    Quote Originally Posted by SemiMan View Post
    Scientific studies can only result in confirmation bias if the outcome is one that is generally known or accepted. That absolutely is not the case in this study.

    People also like to keep believing what they believe even proven not true.

    The study was not about what color you like it was is this color white. If not , how do you think it differs from white. Given that people would not even know what CCT they were being shown how could they have confirmation bias? Without relative comparison or references it hard to pick CCT ... You just know whether it looks sort of reddish yellow, too bluish, or WHITE ... Exactly what the study was trying to figure out .. Where was that point.


    Of course another thing that happens is people bash studies or jump on the study bandwagon without reading them and understanding them.
    The whole idea of a study to figure out what is "subjectively" pure white is a joke. 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. It isn't like someone else's opinion is a predictor of your own opinion...you can't generalize to a population at all, since it is by definition an individual perception. If you want to know what is subjectively pure white, just announcing your own opinion has exactly the same scientific value, i.e., none.

  30. #60

    Default Re: What colour temperature is subjectively closest to "pure white"?

    Quote Originally Posted by thedoc007 View Post
    The whole idea of a study to figure out what is "subjectively" pure white is a joke. 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. It isn't like someone else's opinion is a predictor of your own opinion...you can't generalize to a population at all, since it is by definition an individual perception. If you want to know what is subjectively pure white, just announcing your own opinion has exactly the same scientific value, i.e., none.

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

    Everything we do concerning color is "subjective" but overall, the information is very useful and informative and surprisingly consistent across the population. What people like in terms of lighting is also quite consistent across the population at any given CCT as well (proven in another study).

    Why do people put down well thought out scientific research and studies when they have no clue about the methods employed (or possibly the value of them).

    The reality is that YES you can generalize to a population, especially when the study shows that most participants in the study (blind study - no pun intended), had almost exactly the same results. That is highly useful. Just like a related study that showed across a reasonably good sample size that most people, at any given CCT, prefer a light that falls below the black body.

    When a bunch of people in a well thought out study ALL say that pure white is pretty close to the same spot, then yes you can generalize that answer to the wider population. No it is i not going to be right or perfect for everyone, but if you are designing lights, using lights, designing a scene, etc. that you want the majority of the population to think is "pure white", then obviously it is the right CCT of white (on the blackbody) to pick. It is perhaps why "neutral" white is probably the most popular color by us flashaholics as well ... and if you are designing a flashlight you want people to like, perhaps that will influence your decision.

    Similarly, if you are looking to pick a color point that a majority of people are going to like at a given CCT, or even an adjustable CCT light source that people are going to think it is pleasant, then you are better off moving the color point below the blackbody ... AND NOT on the blackbody. The light that is considered to be the most pleasant IS NOT 100 CRI. It is intentionally less. In a similar respect, when buying fabrics, especially whites, people like "bright white" and colors that pop ... also not 100CRI and hence why Philips has released a lower CRI bulb that retail likes because clothes viewed under it are pleasant to the prospective purchaser.

    One persons subjective impression of a study caused by lack of knowledge does not mean the study is of no value.
    Last edited by SemiMan; 09-03-2014 at 08:57 PM.

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