Nikon LS-3510 Software Reference Manual page 41

Using The Macintosh Scanner Plugin
Since you don't want the width to change, unlock the proportions and type 10
into the height field. The crop's length will change, and you will have an 8" x 10"
crop area in the main crop selection area. Type 300 into the resolution field, and
you have the following:
Fig. 36 Changing Resolution
The crop in the main preview area will look like this:
Fig. 35 Specification Crop
If you attempt to type in a number that is too large, the plugin will beep and
the closest acceptable value will be substituted.
Experiment with the crop selection to see how you can best make use of it. It
will allow enough flexibility to enable any scan that you may wish to make.
Software Reference for Scanners
5-9