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Panasonic TH42PZ70B Calibration

by Vincent Teoh
1 November 2007

Greyscale

As the Panasonic TH42PZ70B doesn't offer white balance adjustment options in the user menu, it's imperative that one of its factory default settings does not stray too far from the D65 video imaging standard. Fortunately [Colour Balance] "Warm" in the [Cinema] picture preset yielded a correlated colour temperature (CCT) that was within 500k of 6500k from 10% stimulus onwards. A slight deficit in red throughout the whole luminance range meant that delta errors (dEs) were never below 4, but this was still one of the better out-of-the-box greyscale performance I've seen on recent flat panel HDTVs:

Warm CCT Warm RGB Tracking
[Colour Balance] "Warm" CCT
[Colour Balance] "Warm" RGB Tracking

By breaking into the service menu to tweak the RGB cuts and gains, I improved greyscale even further with dEs of less than 4 from 20% luminance upwards. I don't recommend doing this unless you have the necessary calibration tools and experience, as you run the risk of voiding your warranty and/ or causing irreparable damage to your television.

Calibrated Warm CCT Calibrated Warm RGB Tracking
Calibrated "Warm" CCT
Calibrated "Warm" RGB Tracking

Colour

After getting greyscale in order, there was precious little I could do to improve the colours because of limited adjustment options both in the user menu and service menu. [Colour] affected the saturation and luminance of all the primaries, whereas [Tint] would rotate all three secondary colour points, meaning that aligning any particular colour would inevitably corrupt the rest. [Colour Management] had no discernable effect other than mildly altering the hue of cyan. This is the final gamut plotted against Rec.709 HD reference:

CIE Chart

Similar to previous plasma televisions from Panasonic, green (and to a lesser extent red) primary on the TH42PZ70B was oversaturated. Colour decoding exhibited some errors as well: green underperformed while red was just a touch over. Like most TVs there was no independent colour decoding control available on the Panasonic TH42PZ70B so it wasn't possible to correct these errors. That said, most people probably wouldn't be able to pick these colour inaccuracies up in real-life material unless they had a reference display with which to compare.

Benchmark Test Results

Dead/ stuck pixels 0
Screen uniformity Perfect
Overscanning on HDMI/ component 0% when [Overscan] is set to "Off" (1080 source)
Blacker than black Passed
Black level Excellent
Black level retention Unstable though very subtly so
Colour chromaticities Average
Scaling Above average
Video mode deinterlacing Good; effective jaggies reduction
Film mode deinterlacing Non-existent (failed 3:2/ 2:2 cadence on all resolutions)
Viewing angle Excellent (above 150°)
Motion resolution (6.5 ppf) 1080
Digital noise reduction Very good; hardly noticeable at 8 feet
Sharpness Defeatable edge enhancement
1080p/24 capability (PS3) Accepts 1080p/24 from PS3
1:1 pixel mapping Yes, when [Overscan] is set to "Off"
Image retention Very mild during first 200 hours
Posterization Less compared to previous Panasonic plasmas
Phosphor trails Yes; severity depends on individual susceptibility

Black Level

The black level on Panasonic TH42PZ70B could not match that on the Pioneer Kuros, but was still a shade darker than on the Samsung F86 and Sony W3000 I tested recently. This was helped in part by some undefeatable dynamic dimming when there's no light output on screen, but like many previous Panasonic plasmas, the black level fluctuation took place very subtly, and so presented less of an issue than the implementations on other brands.

Static Resolution

While the Panasonic TH42PZ70B managed to resolve every single pixel-wide lines both vertically and horizontally over HDMI, the lines were rendered in shades of light and dark grey rather than the clean crisp alternating black and white lines seen on the Sony W3000 and Samsung F86, indicating some roll-off in bandwidth.

Over component things were worse. Not only did the Panasonic TH42PZ70B fail to resolve the vertical (1920) single-pixel lines, the horizontal (1080) lines also betrayed more noise and interference compared to HDMI.

Motion Resolution

Here the Panasonic TH42PZ70B put in a stellar performance. Using Chapter 31 of the "FPD Benchmark Software" as my test pattern of choice for motion resolution, the TH42PZ70B successfully resolved the maximum 1080 lines scrolling horizontally at a speed of 6.5 ppf (pixels per frame). In other words, whereas on other televisions the 4 lines would blur and merge together around the 600 mark when the image started scrolling, on the Panasonic TH42PZ70B I saw the 4 lines as separate all the way up to 1080 resolution. Granted I have only acquired this test disc 1 week ago, but I've been backtracking to test this on some of the more recent flat panel HDTVs I've reviewed... none attained such an impressive motion resolution result.

Video Processing

Video deinterlacing on Panasonic flat screen TVs I have tested over the past year has left a lot to be desired, but the Panasonic TH42PZ70B delivered a surprisingly solid performance. In HQV Benchmark (both Blu-ray and PAL editions), jaggies only started appearing around 20° from horizontal in the rotating wheel pattern. Similarly, the top two bars were smooth in the bouncing bars pattern, earning the Panasonic TH42PH70B a "Good" rating.

The same cannot be said of film mode deinterlacing which was pretty much non-existent on the Panasonic TH42PZ70B: the plasma failed the 3:2 and 2:2 cadence tests over 480i, 576i and 1080i. I even tried all the picture presets in the off chance that 2:3 and/ or 2:2 pulldown was embedded within one of them, but alas, there was no redemption.

This essentially means that line twitter, jaggies and moire will be present during movies. For critical viewing, I strongly recommend sending a progressive signal to the TH42PZ70B (i.e. let the playing device do the film deinterlacing).

The Panasonic TH42PZ70's image was clean enough without engaging [P-NR] which pruned some fine detail even in the "Min" setting. False contours were kept to a minimum... the least I have seen on a Panasonic plasma.

1080p/24 Capability

The Panasonic TH42PZ70B accepted 1080p/24 signals from the Sony Playstation 3 in both the [BD 1024p 24 Hz HDMI] "Automatic" and "On" mode, but exhibited a touch more judder than the Pioneer PDP-508XD and the Samsung LE52F96BD when I scrutinised the scrolling end credits of Casino Royale BD, making me suspect that the Panasonic wasn't refreshing at a multiple of 24Hz. Nevertheless, the judder was extremely subtle; most viewers should still be happy enough with the result.

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