Merge Front and Back Scan Pages
Scanning double-sided documents in two passes produces two separate files: one with all the front sides in order and one with all the back sides. Alternating these two files produces a properly ordered document.
The scanning scenario
Many document scanners offer a manual duplex option: scan all pages face up, flip the stack, scan the backs. This produces File A with pages 1, 3, 5... and File B with pages 2, 4, 6... (in the order they were scanned). Alternating merge reassembles them into 1, 2, 3, 4, 5, 6... order.
Matching the back scan order
When you flip the stack and scan the backs, the order may be reversed: the last page's back is scanned first. You may need to reverse File B before alternating merging. Some scanners handle this automatically; check your scanner's documentation.
Frequently Asked Questions
My back pages are in reverse order. How do I fix this?
Open the reversed PDF in a PDF editor and reverse the page order before uploading to Drive. Then run the alternating merge with the corrected file.
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