UPDATE, FIX DISCOVERED: Users clktmr and markone have uncovered and fine tuned a fix that will restore sets to their original black levels. Mironto has put together an amazing guide detailing the process.
So I knew this has been a problem with Panasonics in the past, but I was kind of hoping it was going to be gradual and not so drastic if it happened at all on the new models. I currently have less than 400 hours on the set. Last set of readings I took before I noticed the (obvious) difference was on the 21st of July, and they were still showing the expected range of 0.008-0.010fL. I was able to duplicate this measure at least 5 or 6 times and never once recorded anything higher. Then came last night, I turned the TV on and it was like a slap in the face, I thought I had changed a setting somewhere (RGB levels, or jacked up brightness somehow), but everything was the same. I got out my meter and measured a surprising .017-.019fL range. I should emphasize I only got out the meter because the difference was so dramatic. It was not a matter of confirming there was a problem, it was a matter of confirming how bad the problem was. Any ideas what could be causing this? Maybe a power supply problem or something? Kind of got me thinking about HDGuru's unexpected MLL findings in their G10/V10 comparison--2 panels that are known to produce near identical black levels. I'm concerned this may be "by design" so to speak.
50G10 Contrast Ratio @ ~200 hours: 4906:1--Black Level 0.008fL, 40fL Windowed White Peak
50G10 Contrast Ratio @ ~400 hours: 2348:1--Black Level 0.018fL, 40fL Windowed White Peak
Cnet 12G (2009 Models) Test Results: Black Level rose from 0.008fL to 0.023fL by 1500 hours
This represents an ~66% reduction in the Contrast Ratio at identical settings--eg. 5000:1 down to 1700:1
Cnet 13G (2010 Models) Test Results: Black levels rose from 0.007fL to 0.012fL by 2500 hours (G20) and 0.004fL to 0.007fL by 1500 hours (VT25).
Tests are still ongoing. Panasonic's Bill Schindler has confirmed to Cnet those are not final values and that they will rise further.
Panasonic's Official Response to the Issue as of 2/4/10
"Automatic Control of Contrast over Operational Lifetime."
Panasonic Viera plasma HDTVs deliver exceptional picture performance throughout the lifetime of these products. Various elements and material characteristics of all electronic displays change with use over time. In order to achieve the optimal picture performance throughout the life of the set, Panasonic Viera plasma HDTVs incorporate an automatic control which adjusts an internal driving voltage at predetermined intervals of operational hours.
As a result of this automatic voltage adjustment, background brightness will increase from its initial value. After several years of typical use, the internal material characteristics will stabilize and no additional automatic voltage adjustments are required. The Black Level at this stabilized point will yield excellent picture performance.
The newest Viera plasma HDTVs incorporate an improved automatic control which applies the voltage adjustments in smaller increments. This results in a more gradual change in the Black Level over time."
(Courtesy of Cnet and David Katzmaier)
Q&A with Bob Perry courtesy of Cnet and David Katzmaier
D-Nice, through contacts at Panasonic, has confirmed this rising black level affects all 11G/12G/13G ('08/'09/'10) models at a specific hour count. There is no fix planned and it is apparently an unintentional goof on Panasonic's part. He further suggests this problem is Panasonic exclusive and does not seem to affect other PDP manufacturers (e.g. Pioneer or Samsung). He maintains the final level will represent an ~3x increase over the original value (e.g. 0.008 to 0.024fL), but that April (and later) build dates on 13G's (2010's) have possibly had the increases spread out over a much longer span in smaller increments. *D-Nice is a well known, well reputed Professional Calibrator that has been providing accurate information for several years.*
xrox has discovered patents registered to Panasonic that describe very similar behavior. He theorizes the significance of the change is unintentional and attributed to old software, premature, or overly aggressive voltage changes.
He has also posted a summary of the compiled scientific evidence to serve as a reference, and maintains a Zero BL Research Thread.
Bdmers has translated much of the above techno-jargon and put together a general summary of the how and why this is happening.
Most affected users report that Image Retention and Phosphorescence become significantly worse post-elevation.
THX has expressed some interest in feedback from affected owners with THX Certified models (G10/G15/V10/Z1) at THXDisplays@thx.com
Several news outlets have picked up on the story: Cnet Test Results, Cnet Continuing Test, Cnet 1, Cnet 2, Cnet 3, Gizmodo, Gizmodo 2, Engadget, Slashgear, Home Theater Mag, Yahoo Tech, Highdefdigest, PC World, HDNation Ep34, HDguru, Home Theater Geeks, and The Tech Guy
*The issue has ballooned past the point where it's necessary or practical to link to individual observations, there are numerous reports of affected users (in addition to the below) buried in the thread.*
Several users suspect they have observed the same change: Battousai, Blaken, Pendragoon, akk5000, iVersatile, Plasmafan09, CraigGB, eurocuroc, cold-fusion, smoof15, martin-per, dmichael, MPDamon, exbagboy, tlivesay, killayaw, curly, rick1000
A few users suspect the S1 is affected as well: Lambo, C Tedesco
S2: D-Nice *Pre-April Build, short term test, just represents the point he stopped measuring the panels.
G20: D-Nice *Pre-April Build, short term test, just represents the point he stopped measuring the panels.
G25: Smoof15 *March Build.
V10: Donnymac51 (2000 hour update), schwaggy, jackal2001
G10/G15: slovst, Vistekrebel, Smeg36, Richard, Sakke, gregmp, anthrojohn, Audioitis, meteorwar, erupted, dark662
S1: Yukon Trooper, chad473, johnkollen
11G: DaMaster, TomHuffman
Bdmers and Batpig have put together a graph and Google doc spreadsheet of all posted measurements.
iVersatile reports a panel replacement fixes the issue and restores original levels (though only temporarily). Repair tech was amazed at the difference.
Bucknuts also reports success with a panel replacement restoring levels--likely only temporarily.
There have been conflicting reports of "A-Board" replacements fixing (and not fixing) the problem. The majority suggests this is an unsuccessful fix.
Battousai has had apparent success with an "A-board" and "SS-board" replacement improving levels. Possibly only a temporary fix.
Frequently Asked Questions
"Can this change be calibrated out?"
No, a "Brightness" setting of 0 measures the same MLL. You can see the data here.
"What about the "Black Level" settings of "Light" and "Dark" in the user menu?
This setting has no affect on the MLL of the panel, it just crushes low percent stimuli (shadow detail) to black. The "Light" and "Dark" settings both measure exactly the same on black. I assume the option is intended to increase perceived contrast.
"What model lines are affected?"
There are measured reports for nearly all 2009 models in the measurements section above. The 11G PX/PZ lines from 2008 also seem to be affected. D-Nice's contacts suggested all consumer class 2008, 2009, and 2010 model lines are affected. He has run short term evaluations on the 2010 S2 and G20 and noted ~30-50% inflation. Those values just represent the point he stopped measuring the panels. He maintains the end result will be a 3x increase over the out of box MLL. He has also noted that April (and later) build dates on the 13G's (2010's) have possibly had the increases spread out over a much longer span in smaller increments.
"Why might some suspect their units are NOT affected?
Obviously I can't say with any degree of certainty that every single unit is affected, but I can provide some reasons why it might not be noticeable to everyone. First you have to consider the environment. All these models have relatively poor anti-reflective/light-blocking filters, so any ambient light that hits the screen makes this issue very very difficult to notice. Obviously this describes pretty much everyone, very few people view displays in a totally blacked out room. Taking this one step further, to have a truly accurate recollection and perception of the MLL's, you would have to almost view the panel exclusively in this blacked out room as any washed out daytime or lit use could potentially bias ones impression. Lastly, you have to consider people's performance expectations. Post-elevation, these panels produce MLL's and CR's largely on par with mid-range CCFL LCD's from 2008 (e.g. Samsung A550/650/750/Etc). Most users and reviewers described these makes as having "Strong, Deep Blacks" and "High Contrast Ratio's", so it's understandable why some might not identify this as an issue.
"Whats up with the IR/Phosphorescence? It looks nasty in a lot the pics!"
xrox suggests the most probable explanation is that "pixels that were discharged contain way too much wall charge and therefore cannot be properly activated or deactivated". Whatever the cause, there does seem to be a significant difference pre Vs. post elevation.
*This is my own 65S1 and 50G10. I am using the same meter, camera, and settings for this comparison.*
Below is a direct comparison (same meter, same environment) between an aged G10 and a brand new S1. These screen-caps show 11 readings of a 0% grayscale pattern. Point of interest is the "Y" row, which is a measurement of black in candela/square meter (cd/m^2) units.
65S1 @ < 20 hours of use--Black Level 0.006fL
50G10 @ > 1000 hours of use--Black Level ~0.019fL
Pictures of the above S1 Vs. G10 (same camera, settings, and environment--check the EXIF data):
The user Fahrenheit has been keeping a photo journal of his V10's inflation (update).
The user anthrojohn has posted a before and after pic of his 42G15.
The user L7R has posted some comparison shots of an inflated G10 and low quality LCD.