Epson DS-510 User Manual page 43

You see an Epson Scan window like this:
4. Select Double-Sided as the Document Source setting.
5. Select the original document size as the Size setting.
6. Select one of the following as the Stitch Images setting:
• Top&Bottom: Places the scanned images one above the other.
• Left&Right: Places the scanned images side by side.
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