The second half of double-sided jobs
After printing the odd pages of a document, the even pages (2, 4, 6…) go on the backs of the sheets. Keep Even Pages creates that second file. It is also useful for scans where all the back sides were scanned separately, or for extracting the right-hand pages of a two-page layout.
What happens
Pages 2, 4, 6, 8 and so on are copied into a new PDF in their original order, without any change in quality, text or links. If the PDF has only one page, there are no even pages and the tool tells you so. Your original document is not changed.
Getting the order right
Most printers stack printed sheets face down, so the first odd page ends up at the bottom; when you feed the stack back in, the printer should print page 2 on the back of page 1. If your printer stacks face up, the order is reversed — reverse the even pages with Organize PDF → Reverse all pages before printing.
Common problems and how to fix them
Backs are printed on the wrong sheets: the stack order was reversed — use the reverse option. Backs are upside down: turn the stack 180° before feeding. You only want the back sides of a scan removed: use Remove Blank Pages instead.
Good habits
Print a two-page test first, keep both odd and even files together, and keep the original PDF.