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Aspect Ratio Explained
Aspect Ratio describes the ratio between the width and height of the screen. Choosing the correct aspect ratio depends primarily on what you intend to use your projector screen for. If you plan on watching mostly television, 4:3 aspect ratio will be best suited to you. While if you’re a film buff, 2.39:1 will be the aspect ratio for you. The most commonly used aspect ratio is 16:9.
For example: A projector screen with an aspect ratio of 16:9 will have 16 units of width to every 9 units of height. For comparison a 4:3 screen is more square as there are only 4 units of width to every 3 units of height.
How content looks on different aspect ratios
There is no problem viewing content of a different aspect ratio with your projector screen. You will however observe black bars either top and bottom or to the left and right depending on the aspect ratio of the media you are projecting versus the aspect ratio of the screen.