Epson Expression 1680 - Manual (Page 25)

Understanding EPSON TWAIN Pro Features 2-5
24-bit Color De-screening
24-bit colors, high quality with de-screening to remove moiré
patterns
Note:
A moiré is a cross-hatch pattern that appears on scanned images when
scanning printed material. It is a result of interference that occurs due
to the difference between the pitches of the scanning and the halftone
screens.
16-bit Gray (HiFi)
16-bit gray, best quality output when scanning gray documents
Note:
This setting only has an effect with certain applications, such as Adobe
Photoshop.
8-bit Gray (Std)
256 grays, high quality, and de-screening is selectable (default is
no de-screening)
Line Art
Black and white, draft quality
OCR
Black and white, best quality
Copy & Fax
Black and white, hard halftone, draft quality, Auto Area
Segmentation