Scanner settings: Light and contrast
Select the light and contrast using the Light and Contrast sliders in the Scanner settings dialog.
Light controls the strength of the light used when scanning invoices. The default setting is optimal for normal invoices with a white or lightly colored background in the defined fields. Change it only if background color in the fields reduces scanned image quality. Slide the Light slider to the left (decreasing the value) if the images are particularly light or weak.
The default setting for Contrast is optimal for normal invoices with white and a lightly colored background in the defined fields. Slide the Contrast slider to the left (decreasing the value) only if the contrast of the scanned page is poor. More contrast is better for invoices with good, solid lines.
Not all scanners allow you to adjust the contrast setting.