Panasonic TC-P42X1 Plasma HDTV Review - Blacks & Whites

Blacks & Whites Summary
• Very low black level. • Very low peak brightness. • Mediocre contrast, but didn't suffer from much tunnel contrast or white falloff. • Very uniform screen. • Poor greyscale gamma curve.
	Calibration	Page 4 of 16	Color Accuracy

Black Level (9.51)

The TC-P42X1 had a ridiculously low black level. It measured 0.05 cd/m²: plasmas typically measure around 0.1 cd/m², and our current average black level (which includes both plasmas and LCDs) is about 0.25 cd/m². 

Although the TC-P42X1 had a great black level, we have to throw out a caveat: a low black level doesn't mean the TV has good detail in dark areas. Typically TVs with a poor black level have trouble displaying blacks below a certain level. In the TC-P42X1's case, it is capable of those low levels, but features hardly any differentiation among them. We'll discuss theis more in the Greyscale Gamma section below.

Peak Brightness (2.02)

 Conversely, the TC-P42X1 also has a low peak brightness. In order to calibrate for accurate colors, we had to turn the TV's brightness way down. If you want, you can boost contrast and brightness to get about 181 cd/m², but your colors will suffer greatly. Otherwise, you'll get a peak brightness of 48.98 cd/m², which is very, very low. For comparison, our average brightness result is 286 cd/m². This means bright areas will look grayish, and if any light shines on the screen, the TV's picture won't be able to drown it out.
 

Contrast (5.99)

The TC-P42X1's deep black and weak peak brightness result in a lower than average contrast ratio of about 980:1. The main reason the TV even did this well is because of it's abusrdly deep black level. Other Panasonic VIERA TVs scored similar contrast ratios for similar reasons, with the TH-46P80U netting 1024:1. Of course, this number doesn't quite measure up to the absurd 30000:1 that Panasonic boasts. Although the TV might technically be capable of achieving something similar, such a situation is impossible to realistically achieve: users would have to tweak all the settings for maximum brightness, then tweak them for the minimum result.
 

Tunnel Contrast (9.28)

The TC-P42X1 actually had a great tunnel contrast for a plasma. Typically plasmas automatically dim when a certain percentage of the screen in black. Dimming is bad, because it leads to a loss of detail in bright areas. Though the TC-P42X1 featured this dimming, it didn't occur until about 95% of the screen was black, which is not likely to crop up during normal viewing.

White Falloff (9.73)

White falloff is like tunnel contrast, only we're checking to make sure the peak brightness doesn't fall. Plasmas also tend to do poorly here, as whites tend to get brighter when they take up a smaller percentage of the screen. Since we had to bump contrast down so low, the screen was almost uniformly dim throughout the test. Although this is good for this particular score, it's why the TV had such a lousy peak brightness result.
 

Uniformity (9.38)

There's really not much to discuss here. The TC-P42X1 has a very, very uniform screen. There might have been some negligible flashlighting on the edges of the screen, but that was probably caused by minor reflections off the bezel. This was the only issue we saw. The TC-P42X1 have a nearly pristine uniformity.

Greyscale Gamma (4.53)

The Panasonic TC-P42X1 didn't have a great greyscale gamma: there were issues at pretty much every point in the graph. The blacks were low initially, which is good, but they didn't transition into greys as quickly as they should have. Once you get below a certain level of brightness, you lose a lot of differentiation. This means a lot of detail will be lost in dark areas, which essentially negates the TV's low black level. Any dark areas will appear to be a flat patch of black. Towards the middle, the greys start turning to white more quickly than they should. The bright end of the spectrum, like the low end, suffers from a lack of differentiation.   
 

The below graph shows how the TC-P42X1's greyscale alters as brightness increases. The graph should look like a concave hyperbola. If you'll notice, the black levels start out low and remain low for quite a long stretch. After the greys start coming in, the graph trends up along a fairly flat slope.

In the next graph, we've plotted the TC-P42X1's greyscale on a logarythmic scale: the black line should be a straight, diagonal line. The light blue line represents the median. Ideally, the light blue and black lines should overlap. As you can see, the greyscale response threads across the median, meaning the TV doesn't increase its greyscale evenly.
 

Resolution Scaling (4.83)

The TC-P42X1 has a 720p screen, which is a few notches below the current full resolution HD, 1080p. The TC-P42X1 will need to downscale broadcast HD.  While the TV did an ok job upscaling 480p (standard definition) content, it had a few issues with 1080i. Regardless of the resolution it was trying to handle, however, the TV suffered from nasty overscan issues. The TV features 3% overscan all around, but cuts off slightly more on the right and top of the screen.
 

480p (7.25)
The TC-P42X1 did an average scaling job with 480p. It suffered from the same 3% overscan the native resolution did. Other than this, there weren't significant issues. Text was readable as long as it was a decent size and we didn't see any weirdness in our test patterns.
 

1080i (3.75)
There were some issues with 1080i. Namely, any area with high contrast, such as alternating light and dark lines, will suffer from heavy, flashing artifacting. This resolution also suffered from some legibility issues: text ran into each other, even at a relatively large size.

1080p (3.5)
The TC-P42X1 had the same issues with 1080p as it did with 1080i. This time, however, the issues will all more pronounced. The artifacting was worse, text was slightly less legible, etc.