Some opinions and advice on current calibration requested. (graphs and inexperienced questions within) P55ST30 - AVS Forum
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post #1 of 18 Old 10-17-2012, 01:51 AM - Thread Starter
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The TV I am calibrating is a Panasonic 55" st30.
I calibrated with the goal of 2.4 gamma. Color calibration was done using 75% saturation/ 100% luminance.
I used HCFR window patterns on the avs709 disc. I waited 2 seconds after each pattern was displayed for the TV to adjust.

I am using MPC with MadVR. I tried calibrating with XBMC but the results it gives are very off... Not sure whats going on but MPC seemed to give much more expected results. And is now what I am using as an external player.

I used a i3display pro and plasma spectral sample.

The current settings I have arrived at are... (with comments)
Custom mode
80 contrast (set using ftL as using my HTPC I cant get under 16 to flash. This seems to be normal effect. Set to ~31ftL.)
58 brightness (set to just start to be able to see 17 causing pixels to activate on the screen. This causes nothing to be visible in the black areas of the screen.)
44 color
+2 tint
0 sharpness (seems to be the professionals common setting for this TV. However, looking at sharpness patterns it seems to effect nothing?)
color temp warm 2
color space normal
High red -7
high green 0
high blue +3
low red +3
low green 0
low blue -1
black extension 0
gamma 2.4 (using this because it gets me closer to 2.4 in the gamma chart which is ideally what I am targeting. I decided on this after a lot of reading.. I wouldn't mind hearing more opinions. but fairly well set. I am in a very light controlled room)
panel brightness mid (really want to use mid. low is just a little too dim for my tastes.)
AGC 0
content type graphics (seems to be a common solution to messed up colors with mid panel brightness otherwise)


this seems to be fairly decent. I know its hard to say without references boxes... so moving on..


the end is a little wonky.. could use some thoughts on that.. is blue clipping?


my goal was under 3.. I could spend days messing around for perfection. The blue does something weird at the high end which limited me going up or down as 70 and 80 seemed to be a little too different.


seems like the green luminance has a bit of a problem. I know according to the one excel file it should be roughly 75 or so cd/m and its about 85.... not sure if there's anything I can do about this?


Using the color setting I tried to get the best balance of over and under saturated...

This chart seems packed full of information.. just wish the Y axis was more usually used numbers.. if that makes sense... However, I don't see this chart on here often so I figured I would explain it from the help file.
Quote:
Saturation-difference histogram measures two distinct things. Curves on higher part of the graph show the difference between the measured saturation level and the expected level. The goal is to reach a 0% difference for all curves. Negative values mean a lake of saturation and positive values mean an excess of saturation.

Curves on the lower part of the graph show a delta E between the measured color and the expected color, without taking into account the saturation level. As an example, a measured green with 60% of saturation instead of 50% will have a delta E of 0, contrary to the saturation curves, which will show +10% saturation error. However, whether the saturation is correct or not, if this green is not pure with blue or red component, the corresponding delta E curve would show the error.

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post #2 of 18 Old 10-17-2012, 08:40 AM
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One thing that you need to note that is the 75% saturation patterns in the avshd 709 disc was created with the assumption of 2.2 gamma. If you adjusted your display to have gamma 2.4, I'm afraid the patterns is useless for your case.
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post #3 of 18 Old 10-17-2012, 09:43 AM
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Quote:
Originally Posted by dominickwok View Post

One thing that you need to note that is the 75% saturation patterns in the avshd 709 disc was created with the assumption of 2.2 gamma. If you adjusted your display to have gamma 2.4, I'm afraid the patterns is useless for your case.

I understand gamma defining luminance versus stimulus, but why does it affect saturation?
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post #4 of 18 Old 10-17-2012, 09:52 AM - Thread Starter
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Quote:
Originally Posted by dominickwok View Post

One thing that you need to note that is the 75% saturation patterns in the avshd 709 disc was created with the assumption of 2.2 gamma. If you adjusted your display to have gamma 2.4, I'm afraid the patterns is useless for your case.
Would love some more information on that. Also are there then any discs that have different gamma patterns? I check basically everything available here and none of them have it.

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Originally Posted by slb View Post

I understand gamma defining luminance versus stimulus, but why does it affect saturation?

This is basically what I understood gamma to be. However, with the test patterns on that disc they are at 100% luminance so they should follow any color/ftL calc.

I wonder if there's a calc out there for different gamma luminance goals.

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post #5 of 18 Old 10-17-2012, 10:47 AM
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I believe CalMAN 5 uses the RGB triplets from the AVS disc and you can then use the patterns with any gamma you define in the gamma formula and target exponent options (such as power 2.4 or power 2.2 or BT.1886).
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post #6 of 18 Old 10-17-2012, 11:23 AM
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Quote:
Originally Posted by slb View Post

I understand gamma defining luminance versus stimulus, but why does it affect saturation?

Because the color of anything between 0% and 100% is mixture of red green and blue.
0% satutraion is red green and blue in equal parts.
100% saturation is when at least one component is contributing no light.

To mix the colors to get very specific mix.
So for instance 50% red on the AVS disc is 190,95,95 (79.5%, 36%, 36%).
For a gamma of 2.2 you look at the actual light output and you get red 0.603, green 0.106, blue 0.106 after you run those percentages through the gamma formula.
That specific mix of red, green and blue light give you the x,y target of 0.4589, 0.3322 which is half way between red and white.

When you change the gamma formula, you change the linear light output from a specific percentage, so if we flip to a gamma of 2.4, all the light output drops.
0.795^2.2 =0.603
0.795^2.4 = 0.5758
0.36^2.2 = 0.106
0.36^2.4 = 0.0865

so now instead of 0.603 red to equal parts 0.106 green and blue we have .5758 red to equal parts 0.865 of green and blue. With this different ratio of color the x,y values shift to 0.4725, 0.3324 so with a darker gamma, colors stay a bit more saturated longer.

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post #7 of 18 Old 10-17-2012, 11:51 AM - Thread Starter
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Alright so I did figure out how to change the target gamma in the spreadsheet I have been using.. It certainly changes the values. Seems I am in for another day of calibration. Just when I thought I was near completion.

Thank you for pointing out a serious error.

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post #8 of 18 Old 10-17-2012, 11:55 AM
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Originally Posted by Shinyav View Post

Alright so I did figure out how to change the target gamma in the spreadsheet I have been using.. It certainly changes the values. Seems I am in for another day of calibration. Just when I thought I was near completion.
Thank you for pointing out a serious error.

The fact that we make that easy in CalMAN is one of the nicer features of our software.

While I love to share how it works, I also can't contribute to making HCFR a more usable product.

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post #9 of 18 Old 10-17-2012, 12:01 PM - Thread Starter
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Certainly understand.
The amount you help everyone on this forum regardless of what product they are using is really impressive.

Unrelated to the need for me to change my saturation levels..

Does any of my other charts show anything worth considering?
Any potential ways to flatten my gamma?
Is there some clipping going on?
What about luminance?

I know for an experienced calibrating they have a plan for these situations.. however, I can only find the most basic of calibration guides online.

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post #10 of 18 Old 10-17-2012, 12:20 PM
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Quote:
Originally Posted by sotti View Post

Because the color of anything between 0% and 100% is mixture of red green and blue.
0% satutraion is red green and blue in equal parts.
100% saturation is when at least one component is contributing no light.
To mix the colors to get very specific mix.
So for instance 50% red on the AVS disc is 190,95,95 (79.5%, 36%, 36%).
For a gamma of 2.2 you look at the actual light output and you get red 0.603, green 0.106, blue 0.106 after you run those percentages through the gamma formula.
That specific mix of red, green and blue light give you the x,y target of 0.4589, 0.3322 which is half way between red and white.
When you change the gamma formula, you change the linear light output from a specific percentage, so if we flip to a gamma of 2.4, all the light output drops.
0.795^2.2 =0.603
0.795^2.4 = 0.5758
0.36^2.2 = 0.106
0.36^2.4 = 0.0865
so now instead of 0.603 red to equal parts 0.106 green and blue we have .5758 red to equal parts 0.865 of green and blue. With this different ratio of color the x,y values shift to 0.4725, 0.3324 so with a darker gamma, colors stay a bit more saturated longer.

Thanks Joel. So if I'm using CalMan to calibrate at 75% saturation with target gamma set at 2.4, and using the DVDO Duo as the source, then Calman will automatically calculate and request the correct pattern from the Duo?
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post #11 of 18 Old 10-17-2012, 12:21 PM - Thread Starter
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I may be wrong but I don't think the pattern needs to change. Just the target.

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post #12 of 18 Old 10-17-2012, 12:52 PM
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Quote:
Originally Posted by Shinyav View Post

I may be wrong but I don't think the pattern needs to change. Just the target.

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Originally Posted by slb View Post

Thanks Joel. So if I'm using CalMan to calibrate at 75% saturation with target gamma set at 2.4, and using the DVDO Duo as the source, then Calman will automatically calculate and request the correct pattern from the Duo?

We've played around with doing it both ways, we found that it was easier from a user perspective to keeps the pattern values fixed and update the targets.

When you start updating the patterns and keeping the targets constant, then something like a changing black level (for BT.1886) can cause the chart to looe all it's data or you have to report data for a triplet that you didn't actually measure.

So what we do now is just adjust the x,y targets based on your gamma.
You can choose the luminance level and also weather you like a constant luminance sweep like the AVS disc (at 2.2 gamma the 25%, 50%, 75%, and 100% all have the same Y target)

By default we have the luminance ramping to the grayscale equivalent like so:

Joel Barsotti
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post #13 of 18 Old 10-17-2012, 01:31 PM
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Quote:
Originally Posted by Shinyav View Post

I may be wrong but I don't think the pattern needs to change. Just the target.

Quote:
Originally Posted by sotti View Post

We've played around with doing it both ways, we found that it was easier from a user perspective to keeps the pattern values fixed and update the targets.

That makes sense. Thanks guys.
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post #14 of 18 Old 10-17-2012, 02:56 PM - Thread Starter
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Alright to meet the targets for 2.4 gamma all I really needed to do was change the color to 48 rather than 44.. everything else seemed to stay in line.

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post #15 of 18 Old 10-17-2012, 05:21 PM - Thread Starter
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This is with 2.4 gamma as the target boxes.

The two problems.. at least that I know of are the
blue at the high end..


and my green luminance...

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post #16 of 18 Old 10-18-2012, 02:49 AM
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how did you add the target boxes? did you do it yourself?
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post #17 of 18 Old 10-18-2012, 03:51 AM - Thread Starter
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There's a spreadsheet linked around called gamut, saturation, brightness, dE charts.
I used that for the graph and also to Calc the correct saturation values for different gammas.

Edit: linked at the bottom of first post. http://www.avsforum.com/t/1134710/epson-calibration-guide-1080-1080ub-6100-6500ub-7500ub

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post #18 of 18 Old 10-19-2012, 07:43 PM - Thread Starter
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I have messed around with it further and still have yet to come up with much better. Just a quick bump in hopes someone else see this that has any thoughts on this particular TV.

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