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Is D65 neutral gray or just a tinge blue - Page 3

post #61 of 66
Quote:
Originally Posted by Vic12345 View Post

I'm looking at reflections off white objects.. not sky or sun..I just thought if sunrise is around 2000k I should be seeing a lot of red,yellow at that time, but I don't. I see more reds and yellows at noon... I guess I'll chalk it up to the changing eyes.

It doesn't matter too me if it's purple. I'm just wondering if anyone has any explanation.I know if you don't have enough red in the gains the picture does look as rich.ive always found it hard to get the red gain right on this tv and other tvs(This one only has 2 point) ,as the brightest brights always are leaning blue.I've finally got it about good enough though..if only the flesh control would not leave the red Color in the ears,cheeks,lips when reducing it I could crank up the color more. Oh well I've still got a good tv up to this point.

Yes, there is an answer and it has been mentioned in this thread... what are you missing? The human vision system CHANGES WHAT YOU PERCEIVE, period. We always see the brightest and bluest light as white regardless of the light source... at 2000K color temp, white will be measurably red (and photographically you will also see the red/orange/yellow without our visual system compensating). But when we are IN that 2000K environment in real life, our visual system evaluates the scene and whatever is brightest and blue-est becomes white as far as we are concerned. If we are in an environment where the color temp is 10,000K, within seconds (maybe 15 to 60 seconds) of entering the environment, the predominance of blue will fade and the brightest and bluest light will begin to appear to be white and ACTUAL white objects will appear to be too yellow. It is simply how our visual system adapts. It makes us better at surviving "in the wild" since we can see threats or prey better when our vision adapts as it does. But when it comes to accurate video... our adaptive visual system is our enemy. And that's why we use meters to measure video displays... meters, cameras, and other image capture devices won't be fooled by the ambient light... if the ambient light is red-orange, photographs taken in that light will appear red-orange. If the ambient light is blue, the photos will look blue. That's very different from how we would perceive the scene while in that environment and taking the photos. Since you have no control over your visual system adaptation to changing light conditions, we simply cannot adjust video displays "by eye" because our eyes fool us very easily... which is what makes optical illusions a fact of life.
post #62 of 66
In another thread, I've been having a conversation about the white point:

http://www.avsforum.com/t/1444684/sharp-lc-70le845u-calibration-including-3d

This fellow has posted the results of metering the white level after optimizing with a 10-point adjustment:

http://www.avsforum.com/attachments/67954

The values bounce all over the place from one point to the next. These would show up as multi-color banding on a grey vignette screen.
Wouldn't a professional calibrator compensate for these variations with a bias towards blue the same way that laundry is dyed blue to make whites brighter?
My own preference is to push green-red instead of blue in order to make a mask that is biased slightly yellow.
Also, a question on the mechanics of these sets -- does the white balance have anything to do with linearity of red, green and blue response?
In old CRTs, the screen and drive controls affected everything about each primary color. In LCDs, this effect would have to be simulated. Is it?
My TV came out of the box with the purplish-blue white of LED Christmas lights and red highlights were magenta. It looked like a decrepit CRT with poor red phosphor.
I had to make 2 separate adjustments -- the white balance in the 10-point white temperature and the red gamut in the CMS.
It was an odd coincidence that both effects occured simultaneously, but both owed to the blue predominance in the LED backlight source.
Edited by johnfull - 3/22/13 at 3:25am
post #63 of 66
No a pro calibrator would get everything to line up at the target.

Displays don't typically fluctuate so wildly as to not be able to hit standards.
post #64 of 66
What do you think of the wildly fluctuating chart?


http://www.avsforum.com/attachments/67954
post #65 of 66
Quote:
Originally Posted by johnfull View Post

What do you think of the wildly fluctuating chart?


http://www.avsforum.com/attachments/67954

Those aren't wild fluctuation, that's a chart that's zoomed in too far.

A Que ball looks like Mt. Everest with the right magnification.

Now if it visually looks poor perhaps there is something else going on, but that chart does not show a problem.
post #66 of 66
All greyscale dE's are below 2, and from 10 to 70 the are below 1. That's pretty close to perfect, since a dE difference of 1.8 is not visible.
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