In fact, everything talking about 4K belies the fact that most of the theater installations around the world are basically going at 2K. I mean the only commercial 4K digital cinema projector that I am aware of is the Sony 4K projector. But the bulk of theatrical installations around the world are the Texas Instruments DLP. And its maximum resolution is 2048x1080. I mean, let's face it. The difference between 1920 and 2048 is 6%. Believe me, you cannot see a 6% difference. Six percent is irrelevant.
http://magazine.creativecow.net/article/the-truth-about-2k-4k-the-future-of-pixels