MLStrand56 asked the HDTV & Home Theater about these new 4K HDTVs. "4 thousand WHAT???"
A 4K HDTV, also known as an Ultra HDTV or a UDTV, is a television with approximately 4,000 pixels of horizontal resolution. Or, to be more specific, not quite 4,000 pixels of horizontal resolution. A UDTV actually has 3840 pixels horizontally and 2160 vertically, giving it four times the resolution of standard 1080p.
And yes, there's an extremely confusing terminology change here. For many years, we've been describing television resolution by the exact vertical resolution--480, 720, 1080. Now we're supposed to move to an approximate horizontal resolution--with the familiar 1080p (1920 horizontal pixels) being the equivalent to 2K.
For what it's worth, the xK terminology is only new for consumer technology. Professional digital cameras, scanners, and movie theater projectors have been labeled 2K and 4K for years.
But does 4K make sense in a consumer environment? I doubt it--at least if you don't have a front projector and a wall-sized screen. And even then, you'll get little out of the difference.
Most of what you see in movie theaters these days is in 2K, and it looks great. Most movie theaters have 2K digital projectors, and even the ones with 4K projectors usually run 2K content, because that's what the studios provide. In fact, a great many theaters with 4k projectors never remove their 3D lenses, which effectively turn them into 2K projectors. (Some of them don't even bother to remove the 3D filters, which make them very dark 2K projectors; you'll find more on that issue here.)
Another reason why you don't need a 4K TV: There's no 4K content to speak of. Sure, the TV manufacturers are going to include some content in the TV itself, but that will be limited and possibly not what you want to see.
In the long run, I may be wrong. But in the here and now, 4K TVs are worthwhile only for people suffering from TMM (Too Much Money).
Read the original forum discussion.