A HELPING HAND
Combine separately scanned front and back pages
A scanner without automatic duplex scanning can produce one PDF of front pages and another of backs. Alternate the two sets to restore reading order, reversing the back-page order when the stack was scanned backwards.
Check the source PDFs first
- Choose the front-page PDF in the first field and the back-page PDF in the second.
- Inspect the second file. If its last printed back page comes first, enable the option to reverse the back-page order.
- Combine the files and download the result. Check at least the first four pages, then review the rest of the document before using it.
Which way round are the backs?
Fronts: 1, 3, 5 Backs in order: 2, 4, 6 → do not reverse Backs in reverse order: 6, 4, 2 → reverse backs Expected output in both cases: 1, 2, 3, 4, 5, 6
The reverse option changes the order of the back pages, not their orientation. If a page is upside down, use Rotate PDF pages to correct it separately.
An ordinary merge puts one complete file after the other. It will not alternate fronts and backs, so choose the duplex tool for this task.
Handle unequal page counts
The two PDFs may have equal page counts, or the front file may have one extra page, which stays at the end. Other differences are rejected to avoid silently producing an incorrect alternation.
Equal counts do not prove that the pairing is right. If a scanner removed a blank page in the middle, later pages can be offset. Inspect the originals or scan again with blank-page removal disabled.
Each input is limited to 500 pages and 50 MB. Keep the sources and check the downloaded document’s first and last pairs as well as any blank pages.