Can one "calibrate" to a different color standard than D65? - Page 4 - AVS Forum
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post #91 of 97 Old 08-01-2013, 01:12 PM
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I'm curious from the certified hardware calibrators in this thread, when you calibrate peoples displays, what does the contrast/colour in the user menus usually end up once everything is perfect? for both day and night settings roughly. Or is it once you've changed the service menu settings.... do the user menus remain somewhat defaults for contrast/colour?

As I'm also curious on reading so many things about these forums. Do the certified people check the AVS disc against their settings? I know Michael does from seeing some of his videos. I've read some parts here, some people prefer to see all bars flashing on the white clipping section so they see 253 faintly flashing. Yet in the manual it says to have 230 - 244 flash without discolouration.

Yet I've read some peoples settings with colormunki and according to their settings the gains causing so much discolouration with 100% contrast in Movie as it turns green with, R-Gain 35/G-Gain 49/B-Gain 31. Yes, I know very little settings work from the same tv to another but I find it hard to believe with such high gains unless they haven't checked that it's not discolouring the contrast. As mine had to go into the low 30's to remain grey.

Surely with high gains you have to have lower contrast so there's no discolouration and vice versa?

I'm just curious on the views of the true experts.
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post #92 of 97 Old 08-01-2013, 01:44 PM
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The actual values in the menu don't really matter, it's only the results.

Every manufacturer does different things. Panasonics in the US have different ranges than in the UK and Europe. So can't compare the numbers across anything.

If I was going to generalize, I would say contrast is usually turned down a bit, brightness is adjusted up or down and color and tint are often left at default and the gamut is tuned with CMS controls.


Unless you are using a meter to quantify your changes, you really have no idea what the effect of your changes are.

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post #93 of 97 Old 08-01-2013, 09:50 PM
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Quote:
Originally Posted by subraman View Post

I have to wonder what impact component tolerances have in a totally "digital" TV, where even the adjustments are done computationally. After all, the "1' s and "0"s stay perfect(!) from input to output and we all know computers are unaffected (short of failures) by tolerances.

Just to amplify my earlier remarks with computers specifically in mind. In the computer world, 0's are *usually* represented by an "analog" zero voltage (+/- a volt (ish)) while 1's are represented by an analog -5V (again +/- a volt (ish)) So there *are* analog tolerances even in the computing world. The nominal analog voltage values for the digital zero and one were picked so that the analog tolerances shouldn't effect the digital value ... in theory. wink.gif

That being said, with the quest to design chips with lower and lower power requirements, I suspect that the nominal voltage for "one" has slowly dropped (or risen actually) over time, thus making the margin for error (aka tolerance) in computer components *much* finer. I also suspect that my limited academic knowledge of logic circuit design is quite dated at this point. I never really cared about the hardware per se, I just cared about what you could make it do. The same outlook pretty much applies to my interest in calibrating video displays.
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post #94 of 97 Old 03-20-2014, 02:39 PM
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I think I heard somewhere that if you have a display wherein there isn't enough leeway in the user controls to reduce blue enough to be in line with red and green while simultaneously controlling gamma that you could potentially consider "calibrating" to a slightly higher white point in order to both balance RGB (from a software perspective) and attain your target gamma. Going into the service menu of such a set to address the excess blue would presumably make such an action unnecessary. However, as a thought experiment, let's pretend you can't get into the service menu. In your opinion is the (hopefully) minor deviation from D65 (or as close as such a set will let you get to D65 in the first place) worth attaining the target gamma?

One obvious drawback is that your primaries and secondaries will be affected by the new inaccurate white point, which I think is the whole reason for caring about D65 at all. But, again, if this is what it takes to achieve your target gamma might it be worth it? Or does it depend on how far away your gamma is from target? If so, then for the sake of this thought experiment let's say you're at gamma 1.6 and are targeting 2.3
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post #95 of 97 Old 03-20-2014, 03:54 PM
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You want to minimize error which means if you need to compromise, compromising both gamma and chromaticity would be in order. Also gamma numbers mean different things at different signal percentages. Being off by 0.2 or even 0.4 at 90% isn't the same thing as being off by 0.4 at 35%.

One is not strictly more important than the other.

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post #96 of 97 Old 03-21-2014, 06:34 PM
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Also, the calibration software you use would have to support setting a "custom" calibration target

But there are multiple issues here. If you calibrate to d65 and results aren't terrible but there are some errors. Consider that if you decide to calibrate to d67... EVERYTHING WILL BE WRONG 100% of the time. So if your choice is to use d65 and live with some errors or calibrate to d67 with 100% of everything wrong... you have to choose your poison carefully.

If you use some aim point other than d65, you also have to decide whether you are going to keep using Rec 709 coordinates for primary and complimentary colors... because changing to d67 does not automatically mean you will be using different coordinates for RGBCMY. If you need to change the reference points for your colors, the calibration software would also have to support that. It's not going to be automatically included in all calibration software. But keep in mind that if you were to, for example, change the coordinates for blue... all colors containing blue would be inaccurate 100% of the time.
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post #97 of 97 Old 03-22-2014, 08:24 AM
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It just seems like it`s more trouble then it`s worth . Besides the standard is D65 not D67. Just stick with what we already know smile.gif Sometimes the limitations of your controls will only get you so close and you live with compromises or you do something about it and get hardware with more controls or better working controls if either one is the issue. The art of calibrating is just that, where can you compromise or need to compromise for the lack of proper controls to the picture you do it . In the end it`s not just about perfect looking charts but what the final picture ends up like , viewing real world material.
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