From the Finder desktop, double-click the Lexmark 3500-4500 Series folder.
Double-click the Lexmark 3500-4500 Series Center icon.
From the All-In-One Center, click Preview/Edit to open the Scan dialog.
From the Scan dialog, click 
to open the Scan Settings drawer.
From the Settings tab:
Select a preset scan setting corresponding to your document.
If you are not satisfied with a preset setting, customize the scan settings by adjusting color depth and resolution, and choosing a descreening option if you need to remove wavy patterns from images scanned from magazines or newspapers.
Reduce background noise, if necessary. Select Reduce Background Noise, and move the slider to adjust the level of noise reduction.
From the Adjustments tab:
Adjust the brightness, contrast, and gamma (color correction curve). Move the sliders to adjust the levels.
Sharpen the image. Move the slider to adjust sharpness of your image.
Invert colors. Select Invert Colors to reverse the colors of your image. The effect is similar to that of a film negative.