Aspect ratio is a proportional relationship between an images width and height. It is expressed with two numbers separated by a colon, such as 16:9, sixteen-to-nine. For the x:y aspect ratio, the image is x units wide and y units high). Common aspect ratios include 1.85:1 and 2.39:1 in cinematography, 4:3 and 16:9 in television photography, and 3:2 in still photography). Some common examples in still camera photography are 4:3, 3:2 (1.5:1), and 16:9). The aspect ratio of an image or video defines the proportion between its width and height, and is always expressed as two numbers separated by a colon (x:y) . For example, images with the aspect ratio of 16:9, no matter how big or small, will always have the width of 16 and the height of 9 units of the same length. The proportional relationship between the height and width of a rectangle is what is referred to as an aspect ratio.