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Temperature perception and how it affects "pure white"

post #1 of 16
3/3/12 at 4:20pm
Thread Starter 
Its known that 6500K is the temperature to aim for when calibrating. However, what causes someone's eyes to perceive the pure color white with a 6500K temperature as "ivory colored" white; and, temperatures approaching 8000K-9000K as pure white (not blu-ish)? This is how my eyes see white. Is this unusual?

For example, in real life, I see a white T-shirt, bedsheets, printer/copier paper as pure white (regardless if I look at them under incandescent, florescent, or natural sunlight). If I look at an ISF calibrated TV, they are configured for something like "warm2"; which is supposed to be 6500K. This makes something that should be pure white (white T-shirt, google.com white background, etc) look ivory colored or very yellowish to my eyes; definitely not pure white.

I actually have to change the temperature of a perfectly ISF calibrated TV to "standard" (pushing 9000K) for white to actually look white (not blue-ish at all). If I go higher up to cool (above 10000K, then I start seeing a blue-ish tint in the white color.

It seems a lot of people can look at a PC monitor configured for 6500K, for the www.google.com background and think that it's not any different than the color of a sheet of copy/printer paper. For me, it looks like a manilla/ivory colored; definitely not the same color as what I perceive as white.

So, am I more sensitive to color temperatures or is everyone else seeing colors correctly and I am not. The same goes for closing credits of a movie... where text is supposed to be white.. to me, when a TV is set at warm2, it looks ivory colored. When set at "standard" it looks my perception of what white is.
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post #2 of 16
3/3/12 at 5:18pm
First of all, warm 2 is not a calibrated setting to 6500k. It is highly variable depending on the manufacturer's interpretation. ISF calibration is independent of a preset TV configuration and is actually based on measurements done off the screen. Second, the color of any object that you see is partially a function of the lighting conditions. Even sunlight varies in color temperature during the day. So the only way to get close to natural white is having a pro do a full ISF calibration: cost is a few hundred dollars. Then you can be reasonably sure that the color of white and the grey scale are set properly. Finally, you cannot know that any end credits were supposed to be in pure white or ivory! There is no uniform standard for end credits. They can be in any color the director chooses. So he might choose an off white color to avoid perceived harshness...
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post #3 of 16
3/3/12 at 6:43pm
Thread Starter 
I don't think you're getting what Im saying. First of all, I didn't say that "warm2" had to be 6500K. I was saying "something like"; which most ISF sets seem to end up at a warm temperature preset. Secondly, I do understand the concept of an object looking different based on lighting conditions; which is why I brought the example of objects looking the same to my eyes regardless if under incandescent light, florescent light, sun light, etc. Lastly, I also understand that there is no standard color to closing credits text; however, many of them do use the whitest color possible that the TV can produce (under the calibrated settings).. it was meant to be an example; probably not the best example. Anyway, hopefully, someone else here can help explain what my eyes perceive under these conditions without trying to split hairs about the examples I provided.

Quote:
Originally Posted by wessew10 View Post

First of all, warm 2 is not a calibrated setting to 6500k. It is highly variable depending on the manufacturer's interpretation. ISF calibration is independent of a preset TV configuration and is actually based on measurements done off the screen. Second, the color of any object that you see is partially a function of the lighting conditions. Even sunlight varies in color temperature during the day. So the only way to get close to natural white is having a pro do a full ISF calibration: cost is a few hundred dollars. Then you can be reasonably sure that the color of white and the grey scale are set properly. Finally, you cannot know that any end credits were supposed to be in pure white or ivory! There is no uniform standard for end credits. They can be in any color the director chooses. So he might choose an off white color to avoid perceived harshness...
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post #4 of 16
3/3/12 at 6:58pm
Quote:
Originally Posted by MKANET View Post

Its known that 6500K is the temperature to aim for when calibrating. However, what causes someone's eyes to perceive the pure color white with a 6500K temperature as "ivory colored" white; and, temperatures approaching 8000K-9000K as pure white (not blu-ish)? This is how my eyes see white. Is this unusual?

For example, in real life, I see a white T-shirt, bedsheets, printer/copier paper as pure white (regardless if I look at them under incandescent, florescent, or natural sunlight). If I look at an ISF calibrated TV, they are configured for something like "warm2"; which is supposed to be 6500K. This makes something that should be pure white (white T-shirt, google.com white background, etc) look ivory colored or very yellowish to my eyes; definitely not pure white.

I actually have to change the temperature of a perfectly ISF calibrated TV to "standard" (pushing 9000K) for white to actually look white (not blue-ish at all). If I go higher up to cool (above 10000K, then I start seeing a blue-ish tint in the white color.

It seems a lot of people can look at a PC monitor configured for 6500K, for the www.google.com background and think that it's not any different than the color of a sheet of copy/printer paper. For me, it looks like a manilla/ivory colored; definitely not the same color as what I perceive as white.

So, am I more sensitive to color temperatures or is everyone else seeing colors correctly and I am not. The same goes for closing credits of a movie... where text is supposed to be white.. to me, when a TV is set at warm2, it looks ivory colored. When set at "standard" it looks my perception of what white is.

I guess everyone sees something a little different.. but the reason people don't notice the manufactures have the color temp set to 10,000 or higher is because the human eye is adaptive and will see anything bluish and bright as white. After you watch a properly calibrated set, you see the blue in all the non calibrated set quite clearly... but even then, if you watch it long enough, it looks white..
Have you actually watched a properly calibrated set? I have yet to measure any set that is correct with any preset.. The toshiba I measured the other day was close at 70xx something set to the warmest of the 10 presets..
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post #5 of 16
3/3/12 at 7:32pm
Thread Starter 
Thanks for replying airscapes. Actually, I can see when pure white starts to turn blue; and, it's almost always when approaching 10000K. Around 8000K-9000K is where my eyes perceive to be the sweet spot; where it doesn't look blu-ish or ivory-ish. I have seen 5 completely different TV sets that have been ISF calibrated in the last several years. They all seem a little warm in temperature to me. They definitely produce the same white I would see in the theater; which looks ivory colored as well. I know that this is the color that was intended to be seen; however, it just doesn't look right to me.

It appears that ISF calibration experts insist that 6500K is pure, perfectly balanced temperature; where white will not look ivory colors or blue. The thing I'm trying to figure out is why to me eyes see that as slightly ivory colored. In fact, I've always called the white produced in film/motion pictures/movie theater as "film white". To my eyes, no matter where I look at a white piece of paper, it's still white to me. It's just on TV where my perception of white seems to be different. I'm just wondering why. I've never been able to explain it to anyone before successfully.

Quote:
Originally Posted by airscapes View Post

I guess everyone sees something a little different.. but the reason people don't notice the manufactures have the color temp set to 10,000 or higher is because the human eye is adaptive and will see anything bluish and bright as white. After you watch a properly calibrated set, you see the blue in all the non calibrated set quite clearly... but even then, if you watch it long enough, it looks white..
Have you actually watched a properly calibrated set? I have yet to measure any set that is correct with any preset.. The toshiba I measured the other day was close at 70xx something set to the warmest of the 10 presets..
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post #6 of 16
3/3/12 at 7:51pm
Quote:
Originally Posted by MKANET View Post

Thanks for replying airscapes. Actually, I can see when pure white starts to turn blue; and, it's almost always when approaching 10000K. Around 8000K-9000K is where my eyes perceive to be the sweet spot; where it doesn't look blu-ish or ivory-ish. I have seen 5 completely different TV sets that have been ISF calibrated in the last several years. They all seem a little warm in temperature to me. They definitely produce the same white I would see in the theater; which looks ivory colored as well. I know that this is the color that was intended to be seen; however, it just doesn't look right to me.

It appears that ISF calibration experts insist that 6500K is pure, perfectly balanced temperature; where white will not look ivory colors or blue. The thing I'm trying to figure out is why to me eyes see that as slightly ivory colored. In fact, I've always called the white produced in film/motion pictures/movie theater as "film white". To my eyes, no matter where I look at a white piece of paper, it's still white to me. It's just on TV where my perception of white seems to be different. I'm just wondering why. I've never been able to explain it to anyone before successfully.

You just get used to look at and perceive 9000K temp as "pure white". Try to set the display's white point at D65 (which is different than mere 6500K temp) and look at it for some time (1 or 2 months), thus give some time for your eyes to adapt.

This may not work for you - but it works for me when the same situation happen to me a year ago.
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post #7 of 16
3/3/12 at 7:56pm
Quote:
Originally Posted by MKANET View Post

T

It appears that ISF calibration experts insist that 6500K is pure, perfectly balanced temperature;

It isn't the experts, it is the HD standard Rec 709 that says that is where white is.. Some people are color blind.. most are not. Maybe you see things a bit different than the spectrometer that was used to set white to Rec 709 x=0.3127 y=0.3291 on the CIE 1931 chart? But that is what what white should be for HD video..
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post #8 of 16
3/3/12 at 8:35pm
Thread Starter 
Whatever it is, it's specific to just TVs and theater. It's definitely not an issue otherwise. So, I don't think it's general colorblindness. Interestingly, white looks correct to me usually on PC monitors and mobile phone with modern color LCD screens. Do PC monitors usually come out the box with a temperature that's slightly colder in temperature?

Quote:
Originally Posted by airscapes View Post

It isn't the experts, it is the HD standard Rec 709 that says that is where white is.. Some people are color blind.. most are not. Maybe you see things a bit different than the spectrometer that was used to set white to Rec 709 x=0.3127 y=0.3291 on the CIE 1931 chart? But that is what what white should be for HD video..
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post #9 of 16
3/3/12 at 8:57pm
Quote:
Originally Posted by MKANET View Post

Whatever it is, it's specific to just TVs and theater. It's definitely not an issue otherwise. So, I don't think it's general colorblindness. Interestingly, white looks correct to me usually on PC monitors and mobile phone with modern color LCD screens. Do PC monitors usually come out the box with a temperature that's slightly colder in temperature?

It's good that you're able to percieve the differences in white between the different sets. Many people don't notice or even really care.

As others have mentioned, the human perception of white is very adaptive. If I have customers that have owned a TV for some time and watched it using an uncalibrated mode, I always tell them to watch the calibrated mode exclusively for at least 2 weeks to help them adapt. After having done that, D65 becomes the new "normal".

The other thing is to recognize that you will always be able to tell the difference between the various shades of white. What you need to do is become solidly familiar with the D65 shade of white (what you currently consider to be an ivory colored white) and recognize that the said color is actually "neutral white". Forget about thinking that you will perceive it as "pure white". Once you are well enough familiar with it, you will be able to instantly know if a given device's white is in the ballpark of neutral white or not.

In a way, what you currently call "pure white" is irrelevant. The HD specification defines exactly what the color of white should be and all other colors are derived from it when the TV is displaying its image. Therefore, to get the most accurate color the device needs to be using D65 as its base. If you watch calibrated images exclusively for 2-4 weeks you should get to the point where you consider it to be normal instead of "wrong" (i.e. yellowish).

And yes, most PC monitors are VERY blue (8000K and up) out of the box. As a matter of fact, the factory settings on many (most?) TVs are too.
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post #10 of 16
3/3/12 at 10:02pm
Thread Starter 
Thanks for taking the time to write such a thoughtful reply. Yes, my eyes are very sensitive to color temperature. I've spent almost all my time that I'm awake behind computer monitors (done this since late 80's). I don't think that it would be realistic for me to get all my computer monitors at work ISF calibrated. I've always tried my best to have my TV's at home very close to the same temperature I see on typical computer monitors. It's much easier for me to adjust my TV to match all other displays I see during the day, than the other way around. I'm sure there's a good reason why most displays ship with higher temperatures. I really liked my last Sony Bravia which allowed me to keep the TV at ISF calibration (which had the temperature preset at "Warm1") ...AND I was able to change the "ivory white" color to look white by enabling the "Clear White" setting. I have no idea how that effect worked, but I sure wish all TV's I own had it.

Quote:
Originally Posted by XrstalLens View Post

It's good that you're able to percieve the differences in white between the different sets. Many people don't notice or even really care.

As others have mentioned, the human perception of white is very adaptive. If I have customers that have owned a TV for some time and watched it using an uncalibrated mode, I always tell them to watch the calibrated mode exclusively for at least 2 weeks to help them adapt. After having done that, D65 becomes the new "normal".

The other thing is to recognize that you will always be able to tell the difference between the various shades of white. What you need to do is become solidly familiar with the D65 shade of white (what you currently consider to be an ivory colored white) and recognize that the said color is actually "neutral white". Forget about thinking that you will perceive it as "pure white". Once you are well enough familiar with it, you will be able to instantly know if a given device's white is in the ballpark of neutral white or not.

In a way, what you currently call "pure white" is irrelevant. The HD specification defines exactly what the color of white should be and all other colors are derived from it when the TV is displaying its image. Therefore, to get the most accurate color the device needs to be using D65 as its base. If you watch calibrated images exclusively for 2-4 weeks you should get to the point where you consider it to be normal instead of "wrong" (i.e. yellowish).

And yes, most PC monitors are VERY blue (8000K and up) out of the box. As a matter of fact, the factory settings on many (most?) TVs are too.
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post #11 of 16
3/4/12 at 12:30am
Quote:
Originally Posted by MKANET View Post

I don't think you're getting what Im saying. First of all, I didn't say that "warm2" had to be 6500K. I was saying "something like"; which most ISF sets seem to end up at a warm temperature preset.

Calibrators will generally pick a picture mode as a starting point which tracks closest to the D65 target. On Panasonic plasmas, that tends to be Warm 2.
This minimises the amount of adjustments and lessens the likelyhood of introducing errors. If the 'Cool' setting was the one that was closer, then thats what they'd start with.

I think that displays pushing towards blue OOTB is simply because its easier to forgive. If the display is too red, people look sunburnt. If its too green, people look sickly. If its too blue... people look like Fonzie.
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post #12 of 16
3/4/12 at 2:31am
The whole point of calibration is to give a baseline on which correctly mastered material will produce a faithful representation on your display.

Its not about whether you think whites look pure or not its a simple question of making the display as correct as possible to the end desired visual result from the mastering. If your display is correct and the whites look yellow...they are supposed to look yellow.
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post #13 of 16
3/4/12 at 5:53am
Quote:
Originally Posted by MKANET View Post

T I've spent almost all my time that I'm awake behind computer monitors (done this since late 80's). I don't think that it would be realistic for me to get all my computer monitors at work ISF calibrated.

I to sit in front of a monitor 8-10 hours a day and have done so since the mid 90s. When I purchased a C6 meter and Calman Software last fall, it came with a PC add-on that will perform a 10 point gray scale automatically on the PCs display using the meter and PC add-on. A properly calibrated display is much easier on my eyes. I would never be able to go back to the way it was..
I have since done all my laptops and even the wife is pleased with the outcome.

In the PC world the calibrations is performed in the video card using it's LUTs (look up tables) and these are controlled directly by the the calibration software. Once the client is installed, you make any brightness/contrast adjustments the monitor may have, using the patters in the PC client, then the meter, Calman and Client work together to run and adjust gray scale and gamma.

The pros can perform this service. I have no idea what the labor is, but the end user license is $99 if I recall correctly.
Multiple profiles can be created if you have multiple displays..

If you are interested in reading why TV are not calibrated, maybe get your questions answered, this is an interesting article http://www.tlvexp.ca/2011/12/why-tvs...-from-factory/
There are quite a few good reads on Michael's web site.
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post #14 of 16
3/4/12 at 6:18am
With most displays, the "Warm 2" preset is usually warmer than 6500K, often approaching 5000K, and usually red/yellow tinted. The "Warm 1" preset is often closer, but tends to be in the 7000-7500K range.

And for that matter, 6500K is not the target6500K can be tinted green or magenta, and still be "6500K". The target is D65, which is a specific white point.

And D65 is not a "pure white" eitherit's blue. D55, or more specifically, Illuminant E, is truly neutral white.


Every example you have cited for your "6500K is not pure white" post is not a good choice either. Firstly, without actually being calibrated, you do not have a 6500K/D65 reference to look at.

Secondly, t-shirts, copy paper, bedsheets etc. are not white. Copy/printer paper typically has optical brighteners, which means it's actually tinted blue. The same applies to modern detergents used on "white" clothing.

Daylight changes colour all the time. It will sometimes hit 6500K, but that depends on the time of day, weather, location etc. I know this because a while back, I actually needed 6500K daylight for camera calibration as I did not have any artificial lighting suitable, and that took an hour or two of taking shots of a GMB ColorChecker every few minutes, and verifying with my i1Pro.



And even if you did not consider a D65 calibrated display to look white, that is the target which content is mastered to, and anything else is wrong.

That being said, I have yet to find someone complain that a D65 calibrated display does not look "white". It's those awful "warm" presets that don't.
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post #15 of 16
3/4/12 at 8:51am
What i see in the real world i would discribe as ''Cool White'' and ''Yellowish White''. Never seen ''pure white'' in the real world.

The ''Cool/Cold White'' (Blueish White) is used most/mainly because of the clean/fresh factor < can be seen in ALL laundry detergent commercials > , the Yellowish White is perceived as being dirty white.


^^ its what my eyes tell me, might not be accurate.
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post #16 of 16
3/4/12 at 10:01am
The bottom line is... your eye-brain interface zero in on the brightest and blue-est objects and MAKE that color white even though it is too blue. That means anything 6500K (color temp is really kind of stupid... it is 90-95% influenced by red and blue, green can be WAY too high or WAY too low and you can still measure 6500K) will look yellow. As someone else pointed out, you have to acclimate to 6500K for some period of time (days to weeks) before it begins to look natural if you have been used to viewing something that's too blue. If you acclimate to the warmer reference over a couple of weeks, then switch to a blue-ish color temperature, in literally minutes, possibly even seconds, the new too-blue presentation will look normal/white and when you switch back to 6500K, you'll need days or weeks, again, for it to look normal/correct.
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