Philips 42PFL3704D-F7 LCD HDTV Review - Blacks & Whites |
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Published on October 05, 2009 Comment on this |
Black Level (7.43) One of the more coveted aspects of picture quality is a low black level. A high black level will give dark scenes a bright look. This also means the TV won't be able to protray much detail in dark areas. To give our measurements some scale, a measurement of 0.1 cd/m2 is good. If it's lower than this, it's a great black level; if the level creeps towards 0.2 dc/m2, you start getting bright blacks. The Philips 42PFL3704D/F7 was capable of a decent 0.13 cd/m2. Your blacks shouldn't look too bright, but they won't be nearly as dark as what you'd see on a plasma. One issue to keep in mind: the 42PFL3704D/F7 has a dynamic backlight that can't be turned off. This means the backlights will turn down when a majority of the screen is black. This not only means you'll rarely encounter such a low black level during normal viewing, it means that, if a scene triggers the dynamic backlight, you'll lose details in the bright areas. While we understand why such a feature is often included on HDTVs, we don't understand why so few TVs allow users to switch it off.
Peak Brightness (8.67) For our peak brightness test, we put an all white screen up on the TV, then measure its luminescence. You want a bright TV for a few reasons. First of all, a high peak brightness allows for better detailing during bright scenes. Secondly, it helps the TV achieve a higher overall contrast ratio. A high peak white can also help lessen wash-out from an external light shining on the screen. The 42PFL3704D/F7 performed pretty well on this test, with a total peak brightness of 332.27 canellas per square meter (cd/m2). Typically all you'll need is something above 200 cd/m2. Once you get towards the 400s, your TV starts becoming very resiliant to external light. While light shining on the screen will still pose a problem (as you can read here), it shouldn't be much of an issue. The 42PFL3704D/F7 also shouldn't have any trouble with bright scenes.
Contrast (7.69) As alluded to in the black level section above, TVs sometimes cheat to get better contrast ratios. Some have dynamic backlights that only kick in under certain situations, some measure their whites and blacks at differrent settings. Regardless, those estimated contrast ratios you read, like 6,000,000:1 aren't achievable during normal viewing conditions. The contrast ratio we measure is the maximum you'll see under normal viewing conditions. The 42PFL3704D/F7's bright white and decently dark black add up to an above average contrast ratio. We measured the TV's actual contrast ratio at about 2556:1. This is pretty good for an LCD. It isn't amazing, but typically LCDs don't have amazing contrast ratios. For the average viewer, the 42PFL3704D/F7's contrast ratio will be fine.
Tunnel Contrast (9.01) Tunnel contrast checks to make sure black levels remain consistent, regardless of how much black is onscreen. TVs can sometimes have dynamic backlights, or allow adjacent bright light to wash out the blacks. In the 42PFL3704D/F7's case, it has a dynamic backlight. Fortunately, it won't kick on very often. Even at 90% black the backlights didn't dim. While we'd prefer a dynamic backlight that could be turned off, it's at least sensitive enough that it won't crop up much during normal viewing.
White Falloff (9.25) Our white falloff test checks for consistency in brightness. It's essentially the inverse of our tunnel contrast test. Some of the pitfalls are also the same as said test. A dynamic backlight can kill the bright parts of a dark scene. Also, due to their display technology, plasmas aren't very good at maintaining brightness over large areas. While the 42PFL3704D/F7 didn't have a huge issue, it appears it'll automatically dim an all white screen. We're guessing this is to prevent a movie from blinding you every time the director decides the best scene transition is panning up to the sun, or when some ghost character finally comes to terms with their death and decides to move on. All white screens are more common than you'd think, and while we appreciate the gesture, we would've preferred if this feature could be switched off.
Uniformity (7.25) The 42PFL3704D/F7's screen was pretty uniform on an all white screen, but we saw some issues when it was all dark. On a white screen, there was some dimming around the corners and in the edges, but the middle portion was a solid white. There wasn't any cloudiness or shadowing at all. Dark screens are cloudy with flashlighting in the corners. Even though it has some uneven lighting during dark scenes, it's the kind of picture quality issue the average consumer wouldn't notice.
Greyscale Gamma (1.42) Greyscale gamma refers to the slope along which greys fade to black or brighten to white. Due to the ways our eyes perceive contrast, the greyscale has to be logarythmic. Ideally, if this curve was plotted on a logarythmic graph, it would be a straight line with a slope in between 2.1 and 2.2. We measured the 42PFL3704D/F7's gamma at 3.63, which is significantly higher than it should be. The graph should look like a hyperbola, incrementing slowly in the dark end of the spectrum, then quickly as it becomes more intense. This looks more like a stretched "S." This shape means there's virtually no differentiation towards the deep blacks and a lack of granularity towards the bright end.
Resolution Scaling (6.63) Unless you're very particular with your viewing habits, your TV will often play content that isn't its native format. Standard definition runs at 480p, DVDs use 720p, and 1080i is broadcast HD. Unless you're watching Blu-rays all day, the 42PFL3704D/F7 will have to upscale content to 1080p, so it can play it back. This change requires additional processing, which can cause artifacting and other quality issues. 480p 720p 1080i
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• Decent black level, good peak brightness, and above average contrast ratio.
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