Alternate Merge
Interleave pages from two or more PDFs (ideal for front/back scans)
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About Alternate Merge
Interleaves the pages of two or more PDFs — first page of document A, first page of document B, second of A, second of B, and so on. The second document can optionally be reversed as it is merged.
Both source documents are read and combined entirely within the browser; neither is uploaded to be reassembled.
How to use Alternate Merge
- Load the fronts as the first document and the backs as the second.
- Enable reverse on the second document if the backs were fed in the opposite direction — the usual case.
- Check the preview: page two should be the reverse of page one.
- Merge and download.
On a production
A duplex document scanned on a single-sided feeder gives you one file of fronts and one of backs, and the backs are usually in reverse order. Interleaving with reversal reassembles the original in one pass instead of forty manual insertions.
Frequently asked questions
- The documents have different page counts — what happens?
- Interleaving continues until the shorter document runs out, then the remaining pages of the longer one are appended. A mismatch usually means a mis-feed worth investigating before you rely on the result.
- How do I know whether to reverse the second file?
- Look at its first page. If it is the back of the last sheet rather than the back of the first, it needs reversing — which is what a face-up output tray produces.
- Can I interleave more than two documents?
- Yes, the rotation extends to any number of inputs, taking one page from each in turn. Three-way interleaving is rare but occasionally useful for collated sets.