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Author Topic: Calibrating Plasma Displays  (Read 5499 times)
Ray
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« on: November 22, 2008, 07:51:29 PM »
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I finally bought a 50" Plasma HD display. I'd been holding off because I wasn't satisfied with the results I'd seen in showrooms and in neighbours' homes. I got the impression that color accuracy was greatly lacking. The emphasis seemed to be on dazzling vibrancy and oversaturation. Attempts to reduce such over-saturation seemed to result in inaccurate colors. Skins tones that are a shade too pink seems to be a common problem, as well as blown highlights and blocked-up shadows that often result from an attempt to get skin tones right.

Nevertheless, prices of plasma displays have continued to fall dramatically as contrast ratios have simultaneously continued to rise. There seemed to be no good reason not to get one. I chose a Panasonic with a claimed CR of 1,000,000:1 (I think the 'native' CR, with reference to a single scene, is 30,000:1; still good).

Initial impressions are very positive, sometimes stunning. My Dell laptop sports a Blu-ray player and HDMI output. I can use the Plasma display, through the HDMI connection, as a computer monitor at 1920x1080 resolution. Since HDMI is a 'digital' connection, as opposed to the analog connection of the VGA 15 pin D-Sub, one would expect the results to be a shade crisper. And indeed they appear to be, perhaps even a few shades crisper.

The set can also display jpeg still images from an SD card (up to 16GB SDHC). It automatically downsizes the jpegs to a maximum of 1920x1080. There's a great incentive to revisit my processed images and, where esthetically acceptable, re-crop them to the 16:9 aspect ratio. There is, of course, a resolution penalty with vertically orientated images and I'm not sure if it would be better to make triptychs of relatively unrelated images for the purposes of display.

On this set there's no picture adjustment controls for JPEG stills' mode. You can't adjust contrast & brightness, color etc. Nevertheless, converting my images to sRGB before saving to jpeg and transferring to an SDHC card, seems to work reasonably well with regard to color accuracy and shadow detail, on this Panasonic Plasma. In fact, surprisingly well considering the over all impact. I'm sometimes stunned. From a viewing distance of 6 to 10ft or so, or the sort of comfortable viewing distance from which one would watch a 50" screen, the results look better on this plasma screen than large prints I've made of similar size, on my Epson 7600 printer, viewed from the same distance.

I'm reminded of Bernard's recent article on LL which addressed this possibility of electronic displays taking over from the large format printer. I was very skeptical myself because a current HD display is a mere 2mp (or 6mb), and I see no new higher resolution format on the horizon, as a general standard. How can a 2mp image compete with anything? Well, from an appropriate viewing distance, it can. Buying this set has caused me to re-evaluate my priorities. How the heck can a 6mb (2mp) image displayed at such a large size look so good?

However, to the main point of this post; although images from my new plasma display can be eye-catching and gob-smackingly good, there's still the matter of color accuracy. From this perspective, there are criticisms to be made. For example, green grass can take on an unnatural luminance. It's sometimes so bright and ultra-green, one could be forgiven for thinking that each blade of grass contained its own set of LEDs.

Having failed to get an even remotely acceptable calibration with ColorMunki, a slightly better but still not acceptable result with GretagMacbeth i1, I rang Panansonic technical support in Australia. Wow! What a hostile reception! That I should dare to criticise a Panasonic product put the technician very much on the defensive. We spent most of the time arguing about the semantics of the term calibration. Total confusion followed.

Without going into details, the end result was he couldn't help in any way whatsoever. When I asked if he could recommend a technician who travels to the home to carry out a calibration in accordance with ISF standards, he advised me that such a process would invalidate the warranty. I tried to explain that I process images on a number of computers in different locations and I expect the appearance of such processed images to be the same, whatever the computer. I therefore need to calibrate the Panasonic plasma set to the same standards as my other computers so I can display such processed images with the confidence that the color will be the same, or very similar. I was alarmed that this technician simply didn't appear to appreciate the point. Could just be, he's Australian, or maybe he's scared of losing his job in these tough economic times and has a misguided notion of pleasing his employer, or maybe he's just a plain ignoramus
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kaelaria
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« Reply #1 on: November 22, 2008, 08:26:08 PM »
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Calibration controls are only available through the Service Menu, and getting into that is not documented to the user since it's meant for the technicians only, and there are settings in there that can damage your display.

Google for your model and service menu, most are readily documented.  Once you get in there you will also need to google for the control layouts and find all the controls you need for calibration.  Then get a HD Calibration tool DVD, I use Avia.
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Ray
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« Reply #2 on: November 22, 2008, 09:04:28 PM »
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Quote from: kaelaria
Calibration controls are only available through the Service Menu, and getting into that is not documented to the user since it's meant for the technicians only, and there are settings in there that can damage your display.

Google for your model and service menu, most are readily documented.  Once you get in there you will also need to google for the control layouts and find all the controls you need for calibration.  Then get a HD Calibration tool DVD, I use Avia.

Yes! I figured that out. However, I have no idea if the controls that are available in the service mode are sufficient to do the job. There's also the problem that any calibration in relation to an AVIA disc might not be accurate in relation to an i1 or X-rite colorimeter calibration, that my other computers are subject to.

The point here is that Panasonic, through their technical support facility, have advised me that any adjustments to the set internally, will void the warranty.
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Ray
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« Reply #3 on: November 22, 2008, 09:20:27 PM »
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I actually paid an additional $239 for an extended warranty because I figured this might be the last TV set I'll ever buy. (I'm probably going to be proved wrong on this point, but that was my reasoning.)

If this set does not lend itself to proper calibration, then that's a negative, and I'd like to advertise the fact.
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kaelaria
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« Reply #4 on: November 22, 2008, 09:28:03 PM »
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The vast majority of sets are not able to be calibrated to the degree of a good monitor.  And yes, altering SM controls can void a warranty if done by a non-factory tech.  Buying a TV with the expectation of using it as a calibrated monitor is a risky venture.  No, eyeballing calibration via a DVD will not be as accurate as an colorimeter, but it's really close if you are good at it.  Some ISF techs do have meters to do the job too.
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Ray
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« Reply #5 on: November 22, 2008, 09:54:42 PM »
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Quote from: kaelaria
The vast majority of sets are not able to be calibrated to the degree of a good monitor.  And yes, altering SM controls can void a warranty if done by a non-factory tech.  Buying a TV with the expectation of using it as a calibrated monitor is a risky venture.  No, eyeballing calibration via a DVD will not be as accurate as an colorimeter, but it's really close if you are good at it.  Some ISF techs do have meters to do the job too.

I'm reluctant to spend $300 or $400 on an in-house calibration, especially if it's concentrated on individual devices such as DVD players. Anyone who has calibrated their computer monitor understands that re-calibratioon is advised every month or so, by the software.

I'm very lax about such recomnendations. Once every month is too precise for my purposes. I'm quite relaxed with a re-calibration every 3 months or so. All I want is to get the calibration right in the first instance.
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kaelaria
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« Reply #6 on: November 22, 2008, 09:59:47 PM »
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It's worth it, for CRT sets, as it takes hours to make the adjustments in most cases, involving focusing the guns and using specialty tools.  For flat panels, it's sometimes worth it if your time is very short.

Simply call around to your local techs and ask them if they use a spectro tool or just a calibration disc, if you don't want just the disc version.  For the intended purpose of the devices, the DVD way is perfectly fine, but for critical color work, I can see where you would want more.  I would bet that if you spent the $40 or so on a DVD tool and gave it a shot, you would find yourself very happy doing it yourself - it's not hard.
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Ray
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« Reply #7 on: November 22, 2008, 10:22:52 PM »
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Quote from: kaelaria
It's worth it, for CRT sets, as it takes hours to make the adjustments in most cases, involving focusing the guns and using specialty tools.  For flat panels, it's sometimes worth it if your time is very short.

Simply call around to your local techs and ask them if they use a spectro tool or just a calibration disc, if you don't want just the disc version.  For the intended purpose of the devices, the DVD way is perfectly fine, but for critical color work, I can see where you would want more.  I would bet that if you spent the $40 or so on a DVD tool and gave it a shot, you would find yourself very happy doing it yourself - it's not hard.

Okay! Thanks for your advice. I can get a DVD tool (PowerDVD) which allows for many controls, contrast, brightness, color etc, but the basic calibration of the set seems to require changes that invalidate the warranty. Here is the problem. It's not necessarily a problem for you, and it's not necessarily a problem for me if I take the trouble to circumvent the system. I'm just totally pissed off with a system that requires the end user to stuff around and waste hours of time trying to get the best out of his/her system because paranoid persons in the movie industry are concerned about copyright protection.

My time is valuable. I don't want to waste it on regional coding issues, calibration issues etc, especially when such issues have been sorted. There's no technical problem. There's just a human stupidity problem.
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Ray
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« Reply #8 on: November 23, 2008, 03:30:36 AM »
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Sorry, the regional coding issue has nothing to do with calibration. I just brought in another time wasting issue that the end user has to contend with. The software in my laptop for playback of DVDs and Blu-ray movies has the annoying characteristic of asking me if I want to change region codes when I have only 3 changes remaining. It's already been determined in Australia that region coding is anti-competitive and therefore an unlawful measure. So I spend hours searching for appropriate software on the internet and trying out such software. I eventually buy PowerDVD which works very well with 'DVD Region+CSS Free'. However, 'DVD Region Free' trial version works for only 10 minutes at a time. Whenever I try to buy it, I get a message that the web site is unavailable. Try later, your trial version is good for 3 months. 10 minutes at a time is no good for 3 months. I get the impression that the company that produces this software is engaged in a legal dispute.

When I buy PowerDVD, I choose the Deluxe version instead of the more expensive Ultra version. The Deluxe version does not play Blu-ray. My fault. I should have checked the features more carefully. The trial version played Blu-ray. Do you know how hard it is to get a refund from these people?

I've wasted hours of my life stuffing around with calibration and region code issues. We've got no hope of solving the climate warming issue with such attitudes.
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mbalensiefer
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« Reply #9 on: November 23, 2008, 01:12:30 PM »
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Personally I don't understand how one can taught one's contrast ratio and color range when the colors themself are off--and can't be fixed.

There was another thread I read here about three days ago that linked to a company that brands displays which can BE calibrated professionally.

When I shell out mookoo money to purchase a Blu-Ray player to watch my Planet Earth DVDs on my Hi-Def screen, I don't want my grass to look like someone broke open a glowstick atop it.

Michael
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kaelaria
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« Reply #10 on: November 23, 2008, 01:20:58 PM »
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I'm not sure what your first sentence means, but just about every display can be calibrated.
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JeffKohn
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« Reply #11 on: November 23, 2008, 04:44:45 PM »
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Some of the newer sets actually have a decent color management system in the user menus. But even on the ones that don't, making adjustments in the service menu is pretty low risk and can greatly improve the display's accuracy. Go to AVSForum and you should be able out lots of info about your set.

That said I don't think trying to get your HDTV to look just like your workstation's display is a very realistic goal. Even if you could, you'd probably find the result to be pretty disappointing when watching TV and movies.

You don't really want to use typical PC profiling software. A better approach is to use something like SpectraCal's CalMAN which supports a variety of colorimeters and spectros. There's also an open-source package called HCFR. This thread at AVSForum might be a good place to start for background info on calibrating home theater displays: http://www.avsforum.com/avs-vb/showthread.php?t=852536

BTW the notion that you're going to void your warranty by going into the service menu is poppycock. They probably can't tell if you've been in there unless you really screwed something up, and even if they could tell, they can't deny you warranty service unless they can prove that the changes you made actually damaged the deviced or caused it to fail. I've always used the service menu to calibrate grayscale on my HDTV's, and it makes a big difference. Fortunately most of the other controls I need are in the user menu.
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Ray
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« Reply #12 on: November 23, 2008, 05:07:25 PM »
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Surprisingly, I got an improvement when I used my laptop and the plasma display (as the primary display) after calibrating an old Hitachi LCOS projector using the ColorMunki. In other words, a profile that has been generated in relation to a projector with a relatively low contrast ratio, produces better results than my attempts to calibrate the plasma display in the normal manner one would calibrate a computer monitor.

I've come across some comments on the net which imply that plasma displays in general emit to much infra-red which confuses the colorimeter and software and produces inaccurate readings.

ISF technicians are pretty scarce in my area. Panasonic do not recommend a technician making any adjustments to the set through the service menu and told me that such adjustments would invalidate the warranty. It was quite a heated exchange I had. They were quite adamant, so I'm looking at the options I have. If nothing else works, I'll probably shell out the money to have an ISF calibration. If the set needs repair within the 5 year warranty period, it looks as though I'll have to bring the ISF technician back to restore the factory default settings as a first measure before contacting Panasonic (or the warranty contractors).

Such a procedure does not make me happy. If I'd known this would be the situation, I would not have bought the extended warranty. For example, just ball-park figures, $400 for initial ISF calibration. Set breaks down and I bring the ISF technician out again to restore the settings, say $200. After the set has been repaired under warranty, I bring the ISF technician out a third time to recalibrate the set; another $400. I've just blown $1,000. Am I made of money or what?

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Ray
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« Reply #13 on: November 23, 2008, 05:36:31 PM »
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Quote from: JeffKohn
Some of the newer sets actually have a decent color management system in the user menus. But even on the ones that don't, making adjustments in the service menu is pretty low risk and can greatly improve the display's accuracy. Go to AVSForum and you should be able out lots of info about your set.

That said I don't think trying to get your HDTV to look just like your workstation's display is a very realistic goal. Even if you could, you'd probably find the result to be pretty disappointing when watching TV and movies.

You don't really want to use typical PC profiling software. A better approach is to use something like SpectraCal's CalMAN which supports a variety of colorimeters and spectros. There's also an open-source package called HCFR. This thread at AVSForum might be a good place to start for background info on calibrating home theater displays: http://www.avsforum.com/avs-vb/showthread.php?t=852536

BTW the notion that you're going to void your warranty by going into the service menu is poppycock. They probably can't tell if you've been in there unless you really screwed something up, and even if they could tell, they can't deny you warranty service unless they can prove that the changes you made actually damaged the deviced or caused it to fail. I've always used the service menu to calibrate grayscale on my HDTV's, and it makes a big difference. Fortunately most of the other controls I need are in the user menu.

Thanks for the AVS link, Jeff. The main reason I would like to calibrate this plasma display to the same standard as my computer monitor, is for the purpose of using the set for slide shows. I'm very impressed with the potential of this set to display my photographic images. The resolution is susrprisingly good from a normal viewing distance. However, all the images I would like to display have been processed on a calibrated monitor.

I'm not so concerned about other sources because such sources are extremely variable in image quality. PowerDVD software for playback of both DVDs and Blu-ray have a range of controls which allow one to lift the shadows and change color saturation etc. Used in conjunction with the TV controls, I think one can get a satisfactory result. TV broadcasts seem to be the most variable of all sources. I can look at one particular channel and cringe at the awful color balance, switch channels and the picture is almost perfect.
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