Screen resolutions, monitor sizes and variations in images size

The dimensions of your image on screen will often be very different to the size of the original you are scanning in. The size of the image on screen depends on monitor resolution and monitor size.


• Video cards are able to display a particular set number of pixels horizontally and vertically on the screen. For example, the card may display (width and height ) 640 x 480 pixels or 800 x 600 pixels. For more information on the different display settings click here.
• Physical dimension of the monitor. A large monitor set to 640 x 480 pixels uses larger pixels than a small monitor with the same setting.

1. Two monitors with the same physical dimension, fixed-size image, but different screen resolutions.

Suppose you have a monitor that displays 800 x 600 pixels and you want your image to take up 1/4 of that screen across and 1/3 down, then: 800/4 x 600/3 = 200 x 200 pixels (Figure 1). However, the same image (200 x 200 pixels) displayed on a monitor of the same size but with different resolution (e.g. 640 x 480), will look much larger as it will take up a larger proportion of the screen (Figure 2).

Figure1: Screen Resolution 800 x 600 Image Size 200 x 200

Figure 2: Screen Resolution 640 x 480 Image Size 200 x 200

2. Two monitors with the same screen resolution, fixed-size image, but different physical dimensions.

Suppose your image size is 200 x 200 and the screen resolution of both monitors is the same (e.g. they both have a 640 x 480 screen resolution). The monitors are of different physical proportion, (e.g. one is a 21 inch monitor, the other a 15 inch monitor). In this case the image will take up the same proportion of space in both monitors, although the absolute size of the image is different (larger in the larger monitor).

Figure 3: Monitor Size 21 inch Screen Resolution 640 x 480 Image size 200 x 200

Figure 4: Monitor Size 15 inch Screen Resolution 640 x 480 Image Size 200 x 200

For more information, contact:

Email iaaf@iaaf.uwa.edu.au

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