Jan
15
Aspect Ratio:
The aspect ratio of a picture is its displayed width divided by its displayed height. It is typically shown as “x:y”. For example, the aspect ratio of a high definition television screen is about 16:9.
The outer blue box (2.35:1) and the middle red box (1.85:1) are typically used in cinematography and the green box (1.33:1) is the format of standard televisions. Aspect ratio is also used to describe the shape of a pixel in a digital image.
http://www.filmbug.com/dictionary/aspect-ratios.php