The Plasma TV Blog

Aspect ratio refers to the ratio of the horizontal to the vertical size of the Television screen. The 4:3 aspect ratio screen is more of the square shaped screen. This was the common aspect ratio in the previous generation of TV and especially in CRT units

Aspect ratio does not simply refer to screen size. Video images are recorded in a variety of aspect ratios also. For example, most older and classic movie DVDs like Gone With The Wind and The Wizard of Oz come in 4:3 aspect ratio. Also, most TV broadcast signals, and all older broadcast signals that might be now available on DVD are in 4:3. This means that when they are displayed on a 4:3 aspect ratio screen with a 4:3 aspect ratio projection system, they will most closely recreate the original theatrical experience. Many music videos and concert DVDs also use 4:3 ratio aspect.

It is possible of course to show 4:3 on 16:9 screens. There are going to be certain consequences when you do this. For example, the “window box” effect, black lines that surround the picture as its aspect is expanded or contracted to adjust to the screen. It is important to remember here that the aspect ratio does not limit screen size. A 4:3 TV could have a screen 100 feet high and 80 feet long, and a classic movie on a DVD with 4:3 aspect would look pretty much the same way it did in a movie theater in 1942. It was also be viewed how the director intended it to be viewed.