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

Wurkkos

brickbat

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Care to provide a link to the studies you are talking about? ...

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.

Yes. If a poster is relying on a scientific study, please share it with the rest of us...
 

Anders Hoveland

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

My testing shows 4300K to be the mark, 5000K is still pretty blue.

I agree. I believe moonlight is about 4200K.
4500K is a good cool neutral white.

There is no pure white; you're always going to bias one light source against another, so if you're been in 4300K lighting and move to 6500K, it'll look cold, if you've been in 8000K lighting and move to 6500K, it'll look warm, etc.
It is certainly true that your eyes adjust, and it's easy to forget that you are viewing things under 2800K orange-tinted light. But I believe a person can still tell the difference, if they step back and take a moment to think about what color the light source actually is. Color bias is mostly a subconscious thing. The color of the light will definitely seem different, but I think it is still possible to know and see it for what it is.
 

thedoc007

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

But I believe a person can still tell the difference, if they step back and take a moment to think about what color the light source actually is. Color bias is mostly a subconscious thing. The color of the light will definitely seem different, but I think it is still possible to know and see it for what it is.

The science would suggest that you can't always (often?) see what is...there are multiple layers of perception/interpretation.

http://www.ted.com/talks/beau_lotto_optical_illusions_show_how_we_see
 

NoNotAgain

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

I've seen numerous postings stating that 5500 Kelvin is cool white. Cool white is above 6500 Kelvin.

In the photographic world, 5600 Kelvin is day light full sun temperature. This chart is from one of the major photographic filter manufacturers, Lowel/Tiffen. http://lowel.tiffen.com/edu/color_temperature_and_rendering_demystified.html

colortemp.jpg
 

SemiMan

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

I've seen numerous postings stating that 5500 Kelvin is cool white. Cool white is above 6500 Kelvin.

As there is no standard, your's is just an opinion much like anyone else.

As we are talking lighting, the concept of warm/cool came from fluorescent lighting as it was the first light source that had tailorable white. The first "cool white" was 4000k, and 5500 daylight with some variant on the daylight name for 6500 and 3000K as warm white.

As LED people were not often lighting people they adopted the readily understood warm for 2700-3000, but when they only had 5500-6500K ish at the top end, they called that cool white. Later when they came out with 4000, they adopted neutral white which was pretty a new term in lighting at that point though may be some other references.
 

Anders Hoveland

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

I've seen numerous postings stating that 5500 Kelvin is cool white. Cool white is above 6500 Kelvin.
I do not see how anyone can think 5000K is not cool white, but everyone is different apparently.

5600 Kelvin is day light full sun temperature.
It's important to recognise the distinction between "sunlight" and "daylight". Sunlight is the light coming directly from the sun, after being attenuated through the atmosphere. Daylight also includes the background light from the sky, the addition of which substantially alters the correlated color temperature.
 

chenrazee

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I should complete the sentence as follows: "Right, if you're in a 3000K room, a 4500K light will look pure white. The problem is, once you move to a 6500K room, that same 4500K light will now look warm." So there is no one color temp you can make a flashlight that will look white even a majority of the time, because the environment you're using it in is always changing.

As for lighting your house, you have to be careful with how cool you get, otherwise it just looks like you're lighting your living room with garage worklights; there needs to be a bit of warmth to house lighting to prevent it from looking too sterile. I find ~3500K works nicely in office and bathroom lighting, and ~3000K is about right for bedrooms and living rooms.

FWIW, the Twilight app on android defines 1000K-3500K as Relaxing and 4000K-5000K as Energizing. This fits with the concept of warmer colours in places we relax in (bedroom, lounge, dining room) and cooler colours in places we work in (kitchen, study/home office, garage/shed).
 

wus

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For me it's white when I come from the sunlit outdoors into a house and the light there matches the outside light.

When the tungsten halogen bulb in the entrance to our house failed (a couple years ago) I looked for a bright LED source with high CRI and daylight color. The closest I found (and wanted to afford) was specified with 5000K. This still shines a little bit warmer than the direct sunlight out the door, so I conclude the "precise" white must have a somewhat higher color temperature. This also conforms to school book knowledge, that says a neutral white is around 5500K or 5600K.
 

twistedraven

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If you were to take into consideration spectral balance from an ideal black body source, then 5400k would have the most balanced spectral response-- being objectively closest to a pure neutral white.

However in artificial lighting like LEDs, there's always dips in cyans, deep reds, and spikes in blues.

Now with the objectivity out of the way, it's literally impossible to specify a pure neutral to human perception, because we are by nature, subjective to a core. There will always be relations at play, there will always be 'light a is cooler or warmer than light b', or 'light c is in between a and b in temperature.'
 

DayofReckoning

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I guess one's own perception can play a pretty big role. I have noticed how my own perception of color temperature can change a lot once I use a certain light for a bit, then swap over to another.

For example, when only using my incandescent A2, it's 3350K beam appears almost pure white to me. However, after switching over to a 5000K LED light for a bit, then swapping back to the A2, the A2 will now appear yellowish in color to me.

I don't know what the answer to the OP's question is, but from an LED, 4500K to 5000K appears closest to pure white to me.
 

maxx44

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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.

That's true, 3500K is the most optimal and neutral brightness level. Temperature adjustments is a great and useful thing in such situations, when you're using your thermal binoculars as well. I've recently purchased model AGM Explorator TB75-384, from here ( resource: https://www.agmglobalvision.com/thermal-imaging/thermal-binoculars ), and my basic knowledge about temperature levels helped me a lot with adjustments.
 
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