Issue with calibrating Panasonic ST60 and skin tones - Page 7 - AVS Forum | Home Theater Discussions And Reviews
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post #181 of 205 Old 03-23-2016, 11:59 AM
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I have been struggling with my ST60 calibration and green skin tones (greyscale actually) too back in 2014 (APL patterns and other tricks you can see on previous pages).
No matter how I calibrated with my i1 Display Pro the grey scale always looked non-uniform with greenish or blueish tint and left IR of the patterns for a day (forget that).
Till I found the best way with most natural grey scale that suits the ST60.

Here's how:

Don't calibrate each IRE step (10, 20 ...100) for grey scale, leave all at default 0.
Adjusting individual IRE will screw the uniformity/transition of the greys and make them look like a rainbow.
In fact, don't calibrate the greyscale with a device or patterns at all.

1. Pause any picture on screen and remove all color (Color to 0).

2. Adjust "W/B low G" till the image looks grey with no other greenish or blueish (W/B low B) tint.
Picture->Pro Settings->W/B detail adjustment->W/B low G (I got mine on -2).

Look at a photographers grey and white cards for reference if you have one, they are VERY useful.
Or you can simply find a quality magazine (glossy photo paper) with grey (black and white) image for a reference,

3. Return Color to default (50).

Optional step 4. Calibrate your colors with HCFR small windows till you have the 25% 50% 75% 100% chromaticity saturation points in the most balanced position among themselves (average) for each color.
Colors on the ST60 don't effect the behavior of ABL, only greyscale.

There you go.
I got a wonderful picture with natural skin tones that resembles my calibrated IPS monitor.
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Last edited by James Freeman; 03-23-2016 at 12:12 PM.
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post #182 of 205 Old 03-24-2016, 08:20 AM
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Quote:
Originally Posted by James Freeman View Post
Don't calibrate each IRE step (10, 20 ...100) for grey scale, leave all at default 0.
Adjusting individual IRE will screw the uniformity/transition of the greys and make them look like a rainbow.
In fact, don't calibrate the greyscale with a device or patterns at all.
This goes against the whole idea of calibration the use of a colormeter to adjust the withe point D65. You can eyeball the greyscale till the cows come home. It still won't be accurate.
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post #183 of 205 Old 03-24-2016, 08:45 AM
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I have calibrated many non plasma displays, the ST60 just doesn't behave.
It has uniformity issue, ABL issue and IR issue, together makes the ST60 (or any plasma) impossible to calibrate like you would a static LCD panel.
The ST60 ABL is very sensitive and the more ABL takes effect the more the picture turns green, that's why you have greenish hue when calibrating with small windows.
On the AVS HD 709 calibration disc there is a pattern called "Grayscale Ramp", have a look at it when you're done calibrating your TV.

Last edited by James Freeman; 03-24-2016 at 08:53 AM.
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post #184 of 205 Old 03-24-2016, 10:24 AM
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SECOND TAKE!!
Agree with James, this is the issue I have also seen. The greyscale, as adjusted by Panasonic, measured spot on with my Spectro meter.However, comparing a greyscale ramp displayed on the Panasonic and comparing it with my broadcast standard CRT monitor, the greyscale, particularly in the low end was visibly lacking ‘RED’. I don’t think this is an ABL issue though. This is more to do with the design of the Panasonic plasma panel, maybe producing more infra red output? So, in this case, unfortunately eyeballing is more accurate than a meter. Best bet is to eyeball the display and then balance using a meter. I think the blu ray image would be near perfect once this has been done.
I also think that the source still produces errors. Apart from skin tones, shades of subtle blue can seem very much shifted and overblown.This isn’t the case with other displays.
You can disable or reduce the effect the ABL has on the Panasonic plasma monitors. Not sure if the service mode option is available within the consumer Plasma models?
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post #185 of 205 Old 04-09-2016, 04:53 AM
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Hi, I have not had much time to do my tests. However, I can confirm that the spectro- meter for plasma TV is incorrect. This seems to apply for all plasma displays. I noticed that my Sony looked slightly green in comparison to my grade 1 broadcast monitor, so eyeball the green down by 4% which gave the correct greyscale- tone. This is not an abl issue. So, do not trust the meter settings with plasma displays. I might try my eye-2 colorimeter, as that had specific plasma measurement settings. So eyeball settings will be more accurate than using a meter for plasma displays.
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post #186 of 205 Old 04-09-2016, 05:22 AM
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To add to that, the i1 Display Pro is Colorimeter which uses 3 RGB filters (tristimulus) not a Spectrophotometer.
A Spectrophotometer will read all the light spectrum and apply the "Standard Observer" filters via software, on the other hand the colors that a Colorimeter reads is dependent on the light spectrum and the built in color filter.
So when reading a white patch with a Colorimeter on two different displays with different blacklight technology like Plasma and LCD you will get somewhat different white temperature.
But when reading with Spectrophotometer you will get the same color regardless of the backlight spectrum because the filters are a mathematical equation and are far more accurate.

You CAN calibrate a plasma with a colorimeter but you have to have a correction matrix from a spectrophotometer with your exact plasma tv spectrum.
Or, you can simple calibrate the plasma as you would an LCD and in the end just eyeball the temperature in comparison to a calibrated LCD. What I did.

I was not joking when I written about using a photographers grey chart to have some reference to look at when eyeballing the greyscale.

Last edited by James Freeman; 04-09-2016 at 05:36 AM.
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post #187 of 205 Old 04-09-2016, 06:14 AM
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Quote:
Originally Posted by James Freeman View Post

You CAN calibrate a plasma with a colorimeter but you have to have a correction matrix from a spectrophotometer with your exact plasma tv spectrum.
Or, you can simple calibrate the plasma as you would an LCD and in the end just eyeball the temperature in comparison to a calibrated LCD. What I did.

I was not joking when I written about using a photographers grey chart to have some reference to look at when eyeballing the greyscale.
You CAN eyeball the two, but to do it correctly the grey card would need to be illuminated by a 5500K light source. That is the color temp it was designed to be accurate under. If its illumination comes from the display, or any other source its apparent color will not be correct. That's why we had viewing booths years ago when I was a professional photographer. Overhead 5500K lights to illuminate grey cards or objects, and a 5500K light box to view transparencies in order to do color corrections.
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post #188 of 205 Old 04-09-2016, 06:38 AM
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Indeed, the grey card I own under normal household fluorescent lighting may look slightly blueish, also under the sun.
You have to have a reference to calibrate by eye, other accurately calibrated monitor or a properly illuminated grey card.
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post #189 of 205 Old 04-10-2016, 07:12 AM
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The problem using grey card is that I cannot trust the light source to be correct. The light source maybe 65k but may exhibit green anomalies?
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post #190 of 205 Old 04-10-2016, 07:31 AM
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Also, my spectro- is good for crt, lcd, dlp and oled, but not plasma. As I say it isn't abl/apl as the measuring patches are visibly greener when seen in comparison to a colour correct display.
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post #191 of 205 Old 04-10-2016, 09:41 AM
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What is the best pattern size to use to eliminate or minimize the "green skin tone" issue?
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post #192 of 205 Old 04-10-2016, 11:30 AM
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Small. However, it would make no difference to green issue. Eyeball green out.
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post #193 of 205 Old 04-10-2016, 11:31 AM
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One method I've found handy for minimizing the potential for color shifts during calibration is to use a small window on a video frame background like this:



You can do this via setting of the desktop background if using a PC to generate patterns, or HCFR has this particular background option available for GDI and chromecast generated patterns.
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post #194 of 205 Old 04-10-2016, 03:31 PM
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If I were you, I'd give RAYJR a shout as he has had an awful lot of experience calibrating those displays and is very good about sharing the secret sauce.
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post #195 of 205 Old 04-11-2016, 07:41 AM
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That will work, zoyd, if the frame is aligned with true north
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post #196 of 205 Old 04-11-2016, 09:46 AM
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post #197 of 205 Old 04-21-2016, 05:11 AM
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Quote:
Originally Posted by delphiplasma View Post
Small. However, it would make no difference to green issue. Eyeball green out.
Is your theory that spectros read the green too low on plasmas?

By eyeballing the green out do you mean using G in 10pt WB controls to lower the green below 100% in the greyscale measurement graph?
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post #198 of 205 Old 04-24-2016, 03:05 AM
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There is something about plasma displays that spoofs the meters. Anyway I ended up reducing green equally from 0 to 100 at each incremental 10 point. A reduction of 4% was all that was required. I'm still running tests on the panny. I will be checking the saturation levels at various points to find out if blue is over saturated at lower saturation levels as blue seems to be wrong, particularly on standard Def material. Reds are a bit orange, but that is due to the phosphor material, which seem similar to the old crt P22 phosphor material.
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post #199 of 205 Old 04-25-2016, 05:42 AM
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Issue with calibrating Panasonic ST60 and skin tones

A first rushed version of my ABL stress test:



https://www.dropbox.com/s/nvgpt0cwf5...tress.mp4?dl=0

On the skin tones issue, this is from another post of mine:

A couple of photos of the VT60 here showing B&W content:





In the first photo, the lower APL upper section of the TV picture skews blue-green.

In the second photo, the higher APL picture part containing the horizontal crossbar skews pink. The crossbar and upright are meant to be the same colour.

Skewing here is relative to the rest of the image. Of course, one has to decide which part, if any, is neutral and which part diverges.
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Last edited by fluxo; 04-25-2016 at 07:16 AM.
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post #200 of 205 Old 04-25-2016, 07:11 AM
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Quote:
Originally Posted by delphiplasma View Post
There is something about plasma displays that spoofs the meters. Anyway I ended up reducing green equally from 0 to 100 at each incremental 10 point. A reduction of 4% was all that was required. I'm still running tests on the panny. I will be checking the saturation levels at various points to find out if blue is over saturated at lower saturation levels as blue seems to be wrong, particularly on standard Def material. Reds are a bit orange, but that is due to the phosphor material, which seem similar to the old crt P22 phosphor material.
I've always ended with subjectively a bit too much green in the picture after my calibrations with an i1 Pro. The last one I did I opted for a bit increased red channel to compensate, but still wasn't quite happy. Windowed, small, big, APL, none of it mattered. I've now tried your advice with reducing the green (always left green controls alone before). Putting Green Gain at -3 seems to have lowered the channel evenly across the whole range, I haven't touched the 10pt green controls.

I've compared the results with my previous run and there is a subtle but noticeable subjective improvement. Unfortunately, I don't have another display to compare it to to see how close to actual proper results I am, but I'm still happier with the new settings so thank you for that tip.

Also, have you noticed that the picture isn't the same between True Cinema and Custom with the same settings? True Cinema seems to have a bit more "pop" to it, like slightly increased contrast or something.

Latest run:



Quote:
Originally Posted by fluxo View Post
A first rushed version of my ABL stress test:

https://www.dropbox.com/s/nvgpt0cwf5...tress.mp4?dl=0
Interesting test. It looks to me like I'm getting a green tinge every so often, e.g. at around 29s and 49s.


Quote:
On the skin tones issue, this is from another post of mine:

A couple of photos of the VT60 here showing B&W content:





In the first photo, the lower APL upper section of the TV picture skews blue-green.

In the second photo, the higher APL picture part containing the horizontal crossbar skews pink. The crossbar and upright are meant to be the same colour.
I LOVE my ST60, but this sure is an annoying issue. I do have to learn to relax more and just watch the content instead of always analyzing it, though
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Last edited by Touche; 04-25-2016 at 07:24 AM.
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post #201 of 205 Old 04-29-2016, 03:45 PM
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So, one issue solved....roll on the next issue. Now my meter shows the display chromaticity to be as good as my broadcast monitor. However, this is not the case. Blue looks way out. I have measured all saturation levels, luminance levels and blue does not come close to reference. The only test the plasma fails is the blue filter test. The blue filter would suggest that blue output on the plasma is low.so I am guessing that the phosphor material for blue cannot be produced for accurate blues and any other colours using blue hue. All this has just made me realise that measurements mean nothing to the display image quality. The only way for accurate picture quality is eyeballing the settings using a professional crt display. And the use a meter to fine tune the results.
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post #202 of 205 Old 11-30-2016, 07:19 PM
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To those who still own the ST60 series.

Does the "skin tone issue" also apply to the 60 inch version of the ST60?

I have the 50 incher and i must say i noticed the issue that OP and others raised.
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post #203 of 205 Old 12-23-2016, 06:24 AM
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Just finished reading this whole thread.

Looks like 50 inch ST60 is really hard to tame using traditional calibration methods (for a plasma).

Now how about 3D LUT calibration? Anyone here tried it? Can the "skin tone" issue in my 50 inch ST60 be tamed with this method?

I'm tempted to buy this hardware and call a professional calibrator

https://displaycalibrationtools.com/...ion-processor/
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post #204 of 205 Old 12-26-2016, 04:38 PM
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Chad B gave me some tips in calibrating the ST60. He mentioned a window size of 5-6% with 18 to 25% APL is ideal.
Adjust 2 pt White Balance, using 100% for the high end but do not use 30% at the low end or you will end up with reddish shadow detail. Either leave the low end alone or do it at 10%. Don't do strong adjustment at the low end.



Start the 10 point by taking a 10 step GS/gamma run (out of the menu) and putting in corrections at the end pass by pass. Don't try to do the 10 point in real time. Just be patient and after each run, analyze the results and put RGB and gamma detail corrections in until you have things looking pretty good. There will be a lot of hopping in and out of the menu.


CMS use 75%a/75%s and then run 25% saturation sweeps at 75%a for final tuning.
Go back to greyscale/gamma. Change to a 19 or 20 point run in 5% increments. Take a full run and do like before, inputting corrections after each run, this time paying attention to the in between increments (15, 85%, etc). Get your overall dE and gamma tracking as good as you can. The key is, don't try to do the 10 point in real time with the menu up. It's a pain, but you need to hop in and out of the menu to do it right.
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post #205 of 205 Old 02-06-2017, 11:12 AM
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Quote:
Originally Posted by hungro View Post
Chad B gave me some tips in calibrating the ST60. He mentioned a window size of 5-6% with 18 to 25% APL is ideal.
Have you tried with his instructions? I'll give the above procedure a try next time I play with my ST60.
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