Advanced Scanning
The Output box in the main window displays the size of the framed original (input size), the scale percentage, and size of the scanned image (output size):
The width and height of the framed original, and the width and height of the output image. The Scale % field shows the relationship between the two.
The image file size
Click this button to switch units of measurement between inches 
and centimeters.
The Output Size Lock locks the final output size.
The Proportional Scaling Lock locks the
Note:
Proportional scaling applies to changes made to either the input frame size or the output size.
Maintaining Size Ratio (Proportional Scaling)
If you were to scale the width on an image differently from the height, the scanned image would look stretched or distorted. Proportional scaling keeps the proportions of an image (width and height) the same when enlarging or shrinking the image.
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