LCD TV Technology: Banding or Screen Uniformity?
Q I was thinking of buying a Sony XBR-65HX950 3D LCD HDTV based on Sound & Vision ’s positive review of that set. [Editor’s note: We actually reviewed the smaller XBR-55HX950.] However, I see plenty of ticked-off people on Amazon complaining about banding issues with that model. Do you consider banding a factory defect or just a quirk that has to be accepted with LCD technology? —Mike Cahan / via e-mail
A I read the comments thread on Amazon about Sony’s XBR-65HX950 TV, and it seems that people are using the term banding incorrectly. Banding typically describes an artifact that shows up as a coarseness between steps in a color gradient. Instead of appearing as a smooth, gradual transition from dark to light hues, the transition looks like a series of stepped “bands.” (An interesting side note: Many Sony TVs, the XBR-65HX950 included, have a feature called Smooth Gradation in their setup menu that really does help to reduce banding artifacts.)
The more likely issue here is screen uniformity. LCD TVs use something called a diffuser to evenly spread the illumination coming from the LED modules in their backlight over the screen’s full expanse. However, with some sets, the diffusion may be less than perfect, with certain parts of the screen appearing lighter than others (screen “clouding” or “spotlights”). It could also be an issue that’s sometimes referred to as “jail bars,” where evenly spaced vertical stripes appear. I understand that LCD TV warranties don’t cover either issue, although most retailers will give you 30 days to return a set that you’re not satisfied with.
Screen uniformity issues are easy to spot when you look at gray full-field test patterns (on test discs such as Digital Video Essentials: HD Basics). You can also see them on regular programs. And they often become worse when you view them from off-center seats. When I reviewed the XBR-65HX950’s little brother, the XBR-55HX950, I didn’t note any screen uniformity problems (or banding), though I did observe that its picture quality became much worse when I viewed from a seat more than 15 degrees off axis.
So, to answer your immediate question, yes, I do consider the TV issue that I believe you’re referring to (poor screen uniformity, as opposed to banding) to be a quirk with LCD TVs, though not of LCD technology in general. Some sets are much better than others in this respect, and the issues have definitely become less severe over the years. To that point, the Sony XBR-65HX950 is an older model that’s since been discontinued. Maybe you should consider buying one of the company’s newer sets instead.