Analog TV was originally fixed at a 4 x 3 image size, one-and-a-third times wide as it is high (hence also known as 1.33:1). It was close to the 1.37:1 ratio established for theatrical films by the Academy of Motion Picture Arts and Sciences. But in the early 1950s, when TV viewing began to cut into movie-theater attendance, movie studios tried various widescreen formats (such as Cinerama, Panavision, and CinemaScope), which could be as wide as 2.76:1. Most of today’s feature films are intended for screening at 1.85:1. (For more about widescreen cinema, see The American WideScreen Museum.)

Widescreen TVs (including all HDTVs) and most widescreen DVDs have a ratio of 16 x 9, or 1.78:1. This allows most films made in the past half-century to be shown full-screen with little or no letterboxing. These screens display older films, and non-HDTV signals, with black bars at the left and right—unless these screens have been adjusted to stretch the image for a fake widescreen effect. Many cinema display computer monitors have a 16 x 10 (1.6:1) ratio. That’s close to 1.618:1, the Golden Rectangle, which Greek geometer Euclid called one of the most pleasing shapes to the human eye. (For more information about the Golden Rectangle, see Wolfram MathWorld.)

Whether the dimension of television screens changes in the future is yet to be determined, but you can be sure that widescreen televisions are here to stay as they can offer the cinema-like experience from the comfort of your living room with exceptional clarity.