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Discussion Starter · #1 ·
Attached is my first attempt at calibrating the grayscale on my Samsung LN52B750. I'm using CalMan with the enhanced Spyder 3. I found that with the "warm 2" color temperature I needed a lot of red and with the "warm 3" color temperature I needed a lot of blue. I went with the "warm 3" color temperature because it was closest to D65.


As you can see, the 10-20 RGB tracking is pretty bad. Is this something I could be doing wrong or a function of the TV? Is it something I could fix in the service menu (I'm only using the user menu now)?

 

first.pdf 97.35546875k . file
 

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Where is your backlight? Looks like your low level luma is dominated by blue, which could just be backlight leakage. Your first two samples are virtually the same level, and rather high, indicating you don't have very good black at all. Turn the BL down if it is up and you should get more of what you expect.
 

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Discussion Starter · #4 ·
Unfortunately, lowering the backlight did not affect my 10-20 readings. I'm still unsure what is causing the problem or how to fix it. The sensor seems to be reading correctly as I can easily see by eye the 20 is much too red.
 

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Scratch my comment about the first two levels being the same. I was misreading the data. Your delta does not make sense for the gray scale you show. There is no way that you should have delta below 2 at zero. Does the 10 and below gray scale look blue.
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by lcaillo /forum/post/16984726


Scratch my comment about the first two levels being the same. I was misreading the data. Your delta does not make sense for the gray scale you show. There is no way that you should have delta below 2 at zero. Does the 10 and below gray scale look blue.

That's what I thought. I'm using the 1994 dE formula if that makes a difference. the dE values don't really make sense to me as I didn't think I was getting that close. I can't really tell if the 10 and below is blue. I can definitely tell that the 20 is too red.


At this point I'm stuck. I'm not sure what I'm doing wrong. Every time I adjust the 30 to be right, 20 goes wacky and way too red. Anyone know if there is a service menu adjustment that will help with this?
 

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Quote:
Originally Posted by ToBeFrank /forum/post/16987053


That's what I thought. I'm using the 1994 dE formula if that makes a difference. the dE values don't really make sense to me as I didn't think I was getting that close. I can't really tell if the 10 and below is blue. I can definitely tell that the 20 is too red.


At this point I'm stuck. I'm not sure what I'm doing wrong. Every time I adjust the 30 to be right, 20 goes wacky and way too red. Anyone know if there is a service menu adjustment that will help with this?

Your readings at 0% and 10% are probably suspect so I would first concentrate on getting the red down at 20%.


Also, read your 0% with the 10% gray showing. That will cut the crazy reading at 0% (which appear to be meaningless anyway) and it will give you a more detailed look at what is going on in the rest of the gray scale.


I don't know why dE is so good, when the RGB is so bad at the low end.
 

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There are 2 issues:


1) Samsung panels are typically not that great at 10% and 20%


2) Absolutely for certain, the Spyder meters are significantly inaccurate below 30% getting worse as the screen gets darker so you can't really trust the readings below 30% too much - you may have to go "by eye" if the meter isn't agreeing with what your eyes are telling you.


Make sure Rec 709/HDTV is your reference color space in your calibration software.
 

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Discussion Starter · #11 ·

Quote:
Originally Posted by orion456 /forum/post/16987233


Also, read your 0% with the 10% gray showing. That will cut the crazy reading at 0% (which appear to be meaningless anyway) and it will give you a more detailed look at what is going on in the rest of the gray scale.

Thanks. I will do this.

Quote:
Originally Posted by Doug Blackburn /forum/post/16988845


There are 2 issues:


1) Samsung panels are typically not that great at 10% and 20%

That could be my issue. How much do 10% and 20% affect picture quality?

Quote:
2) Absolutely for certain, the Spyder meters are significantly inaccurate below 30% getting worse as the screen gets darker so you can't really trust the readings below 30% too much - you may have to go "by eye" if the meter isn't agreeing with what your eyes are telling you.

Being a cheap meter I'm not surprised. The reading at 20% definitely corresponds with my eyes. It is way too red. I figured if I got the 20% pretty close the 10% hopefully wouldn't be too far off. But I'm having a heck of a time getting it there.

Quote:
Make sure Rec 709/HDTV is your reference color space in your calibration software.

Yep.


Thanks much.
 

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Quote:
Originally Posted by ToBeFrank /forum/post/16989695


That could be my issue. How much do 10% and 20% affect picture quality?


Being a cheap meter I'm not surprised. The reading at 20% definitely corresponds with my eyes. It is way too red. I figured if I got the 20% pretty close the 10% hopefully wouldn't be too far off. But I'm having a heck of a time getting it there.

10% and 20% are just as important as other steps. Though you will probably find small errors are less obvious than at brighter steps. But when there is an error that's obvious at 10% or 20% (or even 5%), it can be quite noticeable in movies. One of the arts of calibration is finding compromise settings where none of the errors are too obvious - which is not always possible for every display. And the errors that are visible at 10% and 20% are not equal for each color... blue errors are least obvious. Red and green errors are pretty easy to see. If you have, say, an obvious red error at 5% and you are watching Star Wars or some other movie with outer space depicted... star fields will have a dark reddish background instead of black. That can be pretty off-putting.


Using a graph that shows the relative RGB content for each step is a big help when you are calibrating... you run the entire grayscale then look at ALL the steps and how they react to cut or gain adjustments. When you have to make compromises, this graph is one of the most useful. It will have a horizontal line labeled "100" in the center of the graph - often green is relatively flat and close to "100" and red and blue will vary from step to step (though sometimes green wanders also) - if Red is at "110" for example, that means there is 10% more red than there should be for that step. A color that is at "90" means there is 10% too little of that color for that step.
 
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