Basic Guide to Color Calibration using a CMS (updated and enhanced) - Page 34 - AVS Forum
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Old 12-23-2008, 10:39 PM - Thread Starter
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Quote:
Originally Posted by cvearl View Post

Is there some percentage of Red's color luminance vs. White's you are willing to let go to get closer to Rec 709 on a set like the PZ85U? To help desaturate Red and Green?

This is precisely the issue I address in the tutorial when discussing dE. The 1976 color difference formulas report that the color error produced by oversaturation will be significantly tamed by lowering color brightness. CIE94 does NOT predict this. CIEDE2000 falls somewhere in between, though it is a lot closer to CIE94. This is why I prefer to use %LSH error in conjunction with dE. This shows exactly where the errors lie.

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Old 12-29-2008, 01:28 PM
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I'm learning this as I go along and have spent countless hours calibrating my Samsung LCD but there are so many combinations of inputs, devices, source video types, TV settins, etc that I'm after a bit of help/advice and have a few questions below that I hope someone can help me with.
  1. Do I need to calibrate both for Y Pb/Cb Pr/Cr and RGB or would calibrating for one be the same as the other?
  2. Does anyone know if the Samsung LCD's store seperate settings per input? e.g. If I use Movie mode on both HDMI 1 and HDMI 2 but with differing settings, will they be left intact?
  3. I've using the Blu-Ray version of the AVS HD 709 patterns from these forums and playing them via my PS3. To calibrate for both Y Pb/Cb Pr/Cr and RGB, I'm simply changing the video output in the PS3 between the two to "force" it to output in the desired fashion. Is this OK?
Calibration for XBox 360
I'm calibrating on the PS3 set to output RGB for gaming on the XBox 360. Some questions specific to that;
  1. Should the RGB Range on the PS3 be set to Full or Limited?
  2. Should the Reference Levels on the XBox 360 be set to Standard, Intermediate or Expanded?
  3. Should the HDMI Black Level on the Samsung TV be set to Normal or Low?

Thanks.
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Old 12-29-2008, 03:35 PM
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Tom, thank you so much for your tutorial and your answers to questions in this thread. Your input really helped me decide on buying a Samsung PN50A650 this year because it has a reasonably well implemented CMS with controls that actually do what they're supposed to do, especially considering its price point.

I just got started with my first measurements and adjustments using an i1 Display LT and ColorHCFR and wound up with a bunch of mysteries. However, your posts in this thread cleared up many of my misconceptions and helped me understand how to use the controls effectively.

Your tutorial (along with Kal's dummies guide) got me intrigued about all of this and now I'm kind of happily hooked.
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Old 12-29-2008, 11:56 PM - Thread Starter
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I have added new material to the section on "What's wrong with the ISF conception of color?" and offered my own views as to the relative importance of various characteristics that contribute to image quality.

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Old 12-30-2008, 01:33 PM
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TomHuffman,
Could you please add R, G and B full screen images from 30% to 100% intensity in 10% steps, like you have for white?
I would like to measure my projector primaries coordinates at all these intensities and I can't do it... I think currently your dvd only have 100% and 70%...

Thanks.
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Old 12-30-2008, 05:14 PM
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Hi Tom,

I keep reading that the optimal light output for LCD flat panels is 40 ftL (similar to plasma/CRT/rear projection). However, in your tutorial you state light output for LCD flat panels at 50-60 ftL. Any reason why so high for LCD flat panels?

Thanks
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Old 12-31-2008, 12:06 AM - Thread Starter
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Quote:
Originally Posted by daMaster View Post

I keep reading that the optimal light output for LCD flat panels is 40 ftL (similar to plasma/CRT/rear projection). However, in your tutorial you state light output for LCD flat panels at 50-60 ftL. Any reason why so high for LCD flat panels?

There is no absolute rule about this. The only reason I provide 50-60 fL as a target range for LCDs is that they are generally capable of a very high output--sometimes over 100 fL--without clipping and people generally prefer a brighter image. Personally, I wouldn't go over 50 fL and 40 fL would be perfectly acceptable.

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Old 12-31-2008, 04:17 PM
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are the i1 product able to be used on plasma displays. im intrigued to see if i can expand my diy skills to calibration. thanks for the input
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Old 12-31-2008, 04:35 PM
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Yes, the EyeOne's can be used on plasmas.
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Old 12-31-2008, 04:39 PM - Thread Starter
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Quote:
Originally Posted by yesgrey3 View Post

TomHuffman,
Could you please add R, G and B full screen images from 30% to 100% intensity in 10% steps, like you have for white?
I would like to measure my projector primaries coordinates at all these intensities and I can't do it... I think currently your dvd only have 100% and 70%...

I don't have time for this now, but I have already created 25%, 50%, 75%, and 100% patterns. See

http://www.avsforum.com/avs-vb/showp...&postcount=258

Tom Huffman
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Old 12-31-2008, 06:37 PM
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Hi Tom,
Thanks, it will do it!
I am trying to improve the HTPC CMS solution I have proposed a while back, and need this for some measures. I thought about the 10% steps because it would be more accurate, but this with 25% steps will be good enough for now.

By the way, a Happy New Year, hoppefully with accurate colors for all...
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Old 01-01-2009, 08:16 PM
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happy new years Tom! another hopefully not ignorant question for you. i have really enjoyed this whole calibration thing, and am learning as i go like many here. i heard a piece on the AV rant podcast from audioholics in which Clint said a really cool thing to try was calibrating your tv to 5500 (which i guess would be d55 instead of d65) to watch black and white movies. this sounded like a fun experiment to try, as i watch a lot of black and white movies. i am unsure how to proceed with this though. would you have any simple advice on how to do this? would there be a different set of xyY numbers that would correspond with 5500? thanx again for all your help.

edit: p.s. if it helps any, i am using HCFR software. perhaps there is a way to do it throught the software?
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Old 01-01-2009, 11:51 PM - Thread Starter
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Quote:
Originally Posted by ratso1 View Post

happy new years Tom! another hopefully not ignorant question for you. i have really enjoyed this whole calibration thing, and am learning as i go like many here. i heard a piece on the AV rant podcast from audioholics in which Clint said a really cool thing to try was calibrating your tv to 5500 (which i guess would be d55 instead of d65) to watch black and white movies. this sounded like a fun experiment to try, as i watch a lot of black and white movies. i am unsure how to proceed with this though. would you have any simple advice on how to do this? would there be a different set of xyY numbers that would correspond with 5500? thanx again for all your help.

edit: p.s. if it helps any, i am using HCFR software. perhaps there is a way to do it throught the software?

Just raise the Red gain/bias (whatever they are called on your set) until the color temp measurement in HCFR's combined graph for free measures reads 5500 and blue/green are balanced at a lower level than red..

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Old 01-02-2009, 01:19 AM
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Quote:
Originally Posted by TomHuffman View Post

Just raise the Red gain/bias (whatever they are called on your set) until the color temp measurement in HCFR's combined graph for free measures reads 5500 and blue/green are balanced at a lower level than red..

What about ticking "Change White" and changing D65 to D55 in the Preferences of HCFR?
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Old 01-02-2009, 11:54 AM - Thread Starter
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Quote:
Originally Posted by rickardl View Post

What about ticking "Change White" and changing D65 to D55 in the Preferences of HCFR?

That would work too.

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Old 01-02-2009, 12:11 PM
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Quote:
Originally Posted by TomHuffman View Post

That would work too.

super cool! thanx guys!
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Old 01-02-2009, 08:25 PM - Thread Starter
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I updated the dE spreadsheet at the end of the tutorial to use the raw luma values (fL or cd/m2) to make it easier. I also added EBU as a target gamut and provided the target dE range for each formula.

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Old 01-03-2009, 12:55 AM
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Hi Tom and thanks for the excellent work you do. This test disc of yours, you would not havt it in PAL version? The tracks I am looking for in special is the 75% intensity, window version rgbycmw for colour decoder check.


cheers,


// Keeefan
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Old 01-03-2009, 09:18 AM - Thread Starter
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Quote:
Originally Posted by keeefan View Post

Hi Tom and thanks for the excellent work you do. This test disc of yours, you would not havt it in PAL version? The tracks I am looking for in special is the 75% intensity, window version rgbycmw for colour decoder check.

Added PAL Nero image version.

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Old 01-03-2009, 09:42 AM
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In going through the excellent tutorial, I'm able to get things very close to ideal on my RS2, except the blue component of my luminance is too low across the board. I'm at a loss as to what I should be adjusting to get it more in-line. I have individual color controls for color temp, but those seem to throw off my RGB values, which great for all 3 colors. When I look at my gamma curve, it's close to flat across at 2.2, but my blue component is much higher than red or green. However, when I'm doing my calibration R, G and B are all in the 99%-101% area for each color.

What am I missing?

Thanks.
- Dave
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Old 01-03-2009, 09:45 AM
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Quote:
Originally Posted by TomHuffman View Post

I updated the dE spreadsheet at the end of the tutorial to use the raw luma values (fL or cd/m2) to make it easier. I also added EBU as a target gamut and provided the target dE range for each formula.

Happy new year Tom! And a HUGE thanks for this. I was in the process of trying to create something simular based off your original spreadsheet (failing miserably I might add) and here you come and put it together.

Great work!

For those of you that use the Dummies guide. That guide asks that you use DVE HD for the Greyscale and then switch to the AVS 709 disk for the colors. This is fine I guess but remember that the white reading you took from the Greyscale will not be the same as the one you got from AVS709, Getgray or Tom's during color measurement runs. This is on account of having different Luma values due to different window sizes of the White stimulus pattern. (CRT and Plasma I suspect are all that this effects).

In other words. When you are filling out the spreadsheet, stick with the white you read during the Color run or the Luma will compare wrong and cause an error in the error calculations.

C.

Panasonic 42" Plasma TH42-PZ85U
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Old 01-03-2009, 10:29 AM
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From a calibration and color science industry perspective...

Which do you find most technitians using as a dE guide when working on getting colors as close as they can these days while they are in your home working on your set...

CIELuv or CIE94?

Wondering if I was ever to hire a guy, what I would be most likely to run into as of today.

C.

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Panasonic Blueray Player DMP-BD35
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Old 01-03-2009, 11:45 AM - Thread Starter
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Quote:
Originally Posted by cvearl View Post

From a calibration and color science industry perspective...

Which do you find most technitians using as a dE guide when working on getting colors as close as they can these days while they are in your home working on your set...

CIELuv or CIE94?

Wondering if I was ever to hire a guy, what I would be most likely to run into as of today.

CIELUV is by far the most common, though not the best.

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Old 01-03-2009, 06:59 PM
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So I've been exhausting too much time with the i1 and HCFR.

Without resorting to posting charts, I hope I can convey this appropriately. Prior to adjustment, I had a gamma average 2.27, but it peaked just over 2.3 in low and high IRE. With the settings, my 100% white luminance was 60fL, and the 10%IRE was about .44%. Brightness was as high as I could go without exposing below black. Visually, I think I would like more shadow detail. Using RGB bias settings (and changing nothing else), I can get luminance at 10%IRE to about .6% of white, and upon doing so, the gamma stayed pretty near 2.2 from IRE10 upto about IRE70 where it then dropped off like a maniac (average gamma less than 2.1). dE is below 3 from 30 to 100, and below 6 at 20. Adjusting RGB gain in the high end did not help. Is there a possible remedy for this, or do I have to choose between this white crush and the previous black crush?
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Old 01-03-2009, 07:02 PM
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What kind of display is it?

What you describe is usually solved by turning down the contrast. You need to sacrifice some peak light output to get a smoother gamma.
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Old 01-04-2009, 12:18 AM
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Thanks for the PAL version of your disc, Tom.

All the best,



/Keeefan
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Old 01-04-2009, 10:17 AM
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Quote:
Originally Posted by jvincent View Post

What kind of display is it?

What you describe is usually solved by turning down the contrast. You need to sacrifice some peak light output to get a smoother gamma.

It's a sony XBR8. I've tried turning the contrast down, too. You have to turn it way down to get a peak luminance of 40fL at full white, but this crushes white, too. I think this is a limitation of this display. I can turn the backlight down, but the ratio between full white and 10%gray luminance is preserved when I do this. You have to turn the contrast WAY down to get it right, but the gamma still goes to crap at the high end. None of the reviews of this set are any good. They all talk about blacks and color tracking and temperature, which are all good, but none bother to comment on the grayscale. If you look at their picture settings, all would be subject to the same issue I am having.
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Old 01-04-2009, 10:29 AM
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Tom, my mits 73835 has an auto iris that is not adjustable in any way. Im using an eye one pro with calman along with the 709 disc from here via a ps3. I have already calibrated the set and things came out pretty well but now im curious if i should have used the apl patterns on the disk for grayscale and color since it has an auto iris or just use the regular patterns which is what i used. My calibration came out well except gamma no matter what i do continues to rise and wont track evenly which i know is due to the iris. Any opinion one way or another on which patterns i should have used? Thanks.
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Old 01-04-2009, 01:42 PM
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I went ahead and remeasured using the apl patterns and grayscale is now much to blue compared to when i measure with the normal pattern which is spot on. The gamma also measured differently. Colors were pretty much the same. So now which one is correct? Not sure how to determine whch one to use?
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Old 01-04-2009, 02:42 PM - Thread Starter
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Quote:
Originally Posted by njfoses View Post

I went ahead and remeasured using the apl patterns and grayscale is now much to blue compared to when i measure with the normal pattern which is spot on. The gamma also measured differently. Colors were pretty much the same. So now which one is correct? Not sure how to determine whch one to use?

You are going to have to be more explicit in what you are asking. When you refer to the "APL patterns" and the "normal patterns" I don't know what you are referring to.

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