Use a two-page test to confirm page direction and the correct binding edge.
Check whether duplex is automatic
Automatic duplex turns the sheet inside the printer. Manual duplex asks you to reload the printed stack. Follow the instructions for your tray layout rather than guessing which way the paper goes; feed direction differs between models.
Choose the way the pages will turn
For a portrait document read like a book, long-edge binding is usually appropriate. Short-edge binding suits a portrait document that flips upward. Print a two-page test in your intended orientation before running a report or booklet.
Check the paper limits
The automatic duplex path may support fewer sizes or weights than single-sided printing. Check the manual for the exact paper you intend to use, especially coated or heavy media. Remember that print duplex does not establish two-sided scanning capability.
Sources & further reading
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