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Let’s discuss the other values in the Output Size area.
Lock, when on, freezes the output dimensions (width and height), and
therefore the aspect ratio of the crop box if present. However, you can
still move or remove the crop box.
For example suppose you are working in inches and have specified an
output of 6-inches wide by 4-inches high. If you check Lock on, then
the Width and Height fields will not change as you change other pa-
rameters.
The Magnify field contains the magnification value, stated as a percent-
age; its relationship to other values is explained below.
The File Size area displays the estimated size of the final image file in
megabytes (MB) that will result from a scan using the current settings.
Now let’s look more closely at the relationship between these items. It’s
important to realize that if you change one of these values, the software
may change other values in order to keep their relationship intact. Also
changing one or more values may result in a situation that would force
another setting beyond of the range of the scanner; when this happens the
software warns you that it cannot accept your change.
Formulaic Relationships
Several formulas show the relationship between these parameters.
1. Scan resolution = Output resolution x Magnification
This formula relates resolution with magnification. Consider the com-
mon example in which the size of the output image is larger than the
size of the 35 mm frame. Then the resolution of the input scan must be
spread out to cover the larger area of the desired output image. There-
fore as the magnification increases (the output image gets larger), the
output resolution must decrease or the scan resolution must increase.
Whether it is the scan resolution that changes, or the output resolution,
is described below.
2. Output Width = Input Width x Magnification
Output Height = Input Height x Magnification
These formulas relate output and input width (and height) with magni-
fication. Here, as an example, if we double the magnification then the
output width (and height) will double.
