Magnification text box: to set image magnification. This value equals the input resolution divided by the output resolution, or the output size divided by the input size. The magnification text box cannot be used if pixel is selected in the unit list box.
When the input size and output size are unlocked, the input resolution and output size vary according to the entered magnification value. When the output size is locked, the input resolution and input size vary according to the entered magnification value. When the input size is locked, the input resolution and output size vary according to the entered magnification.
Unit list box: the input and output size unit can be changed: pixels, millimeters, centimeters, inch- es, pica, and points.
Image size display: indicates the file size of the image.
Reset button: to initialize all current settings.
About resolution and output size
Resolution can be expressed in dpi (dots per inch). This refers to how many pixels are placed along one linear inch. A resolution of 350 dpi, which is commonly used in commercial printing, means that an area of one square inch would use 122,500 pixels. The larger the resolution, the greater the detail in the image. However, as the resolution increases, so does the file size.
The image resolution depends on the resolution of the output device. A printer with a resolution of 150 dpi will not be able to print a 300 dpi file any better than a 150 dpi file; the 300 dpi file will just be
Input resolution | = | Output size | = | Magnification factor | |
Output resolution | Input size | ||||
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For example, to make a 144 mm x 96 mm print at a resolution of 150 dpi from 35mm film (image size: 36mm x 24mm), the magnification can be calculated by dividing the print dimensions by the film dimensions: 96 mm / 24 mm = 4 times. The input resolution can be determined from the mag- nification factor: 150 dpi X 4 = 600 dpi.
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