Update June 21, 2011 Since this article posted I've had the chance to recalibrate and test CNET's TC-P55VT30 review sample using the new firmware. As far as I can tell, it did not improve Custom mode's color accuracy, despite Panasonic's claim below. I've contacted Panasonic for an explanation and will provide an update when I hear back.
Today Panasonic has made available a firmware update that's designed to address a couple of issues regarding color calibration in its highest-end plasma TV, the TC-PVT30 series.
I recently reviewed the VT30 for CNET and, despite calling it "the best-performing TV we've tested in 2011," noticed something amiss when performing the standard color calibration in Custom mode:
Our Custom calibration took a while and was hampered by poor menu design with excessive nesting and a need to back completely out of the menus frequently, but afterward our software and charts told us that the VT30's color was nearly perfect (see our Custom post-calibration chart here). Unfortunately, when we looked at actual program material, our eyes told us that colors were still inaccurate, with reddish skin tones and too much saturation throughout. We were mystified because the TV's colors measured extremely well (Delta errors of less than 3 across the board), but compared to other well-calibrated TVs in our lineup, we saw a different story that contradicted the charts. Rather than mess with Custom further to attempt to resolve the discrepancy, we settled on THX for our evaluation. We've contacted Panasonic seeking clarity on this issue and will update this review if we hear back.
Today we heard back from one of the company's engineers via e-mail:
It is necessary to update the firmware to v2.060 in order to correct the COLOR SPACE (aka COLOR GAMUT) in CUSTOM mode. This explains why the colors are inaccurate even after calibrating the unit close to perfection.
In my previous e-mail, I mentioned the two necessary requirements to calibrate the VT30 series properly to get a very good picture (color saturation and hue) satisfying REC709 specs.
1) Set AGC to '0' in CUSTOM PRO-SETTING
2) Update the firmware to v2.060
Here are the changes in v2.060 (related to ISF calibration and picture improvements)
1) Control ISF via ethernet (ISF auto calibration using CalMAN).
2) Corrected COLOR GAMUT (color adjustment in wide color space)
I just went to check for the new v2.060 firmware and, lo and behold, it was available on my review unit (and I assume on every Internet-connected VT30 in the field).
I will report on its effects as soon as possible, including updating the review, related comparisons, and picture settings. I also plan to check out the new ISF control mode in CalMan, although that mode won't affect my calibrations or published picture settings since it's not available to the public via user menus.