From the Finder desktop, double-click the Lexmark 3500-4500 Series folder.
Double-click the Lexmark 3500-4500 Series Center icon.
Click Preview/Edit to open the Scan dialog.
From the Scan dialog, click to open the Scan Settings drawer.
Click the Adjustments tab.
From the Blur/Sharpen area, move the slider to adjust the level of sharpness of the scanned image.