Epson Expression 1680 Reference Manual page 116

Check the brightness and contrast settings of your computer
display.
Image is dark, with little or no detail.
Select Screen/Web as the Destination setting in EPSON TWAIN
Pro. For details, see "Selecting a Destination" on page 2-9.
Note:
Though selecting a printer may cause on-screen colors to differ from the
colors of the original, the colors will be reproduced correctly when
printed.
You cannot scan an image or you only get a few dots for the
scanned image.
Make sure you have placed a document on the document
table.
When OCR is selected as the Image Type, adjust the
Threshold setting in one of the following ways:
Click the Image Type button and change the B/W Option
from Text Enhancement Technology to None. Then, in the
Image Controls dialog box, adjust the Threshold setting.
Change OCR to Line Art, then change the Threshold setting
in the Image Control dialog box. For details on the Threshold
setting, see "Image Controls" on page 2-38.
Character recognition is poor.
Make sure OCR is selected as the Image Type setting.
Try adjusting the Threshold setting in the Image Controls
dialog box.
Select Text Enhancement Technology from the B/W Option
in the Image Type dialog box. This helps to eliminate
background noise.
Maintenance and Troubleshooting
5-15