Manual double-sided printing
Many home and office printers cannot print on both sides automatically. The usual trick is to print all odd pages (1, 3, 5…) first, turn the stack over, put it back in the printer and print all even pages (2, 4, 6…) on the back. Keep Odd Pages creates the first of those two files.
What happens
Pages 1, 3, 5, 7 and so on are copied into a new PDF in their original order, without any change in quality, text or links. A one-page PDF keeps its single page. Your original document is not changed.
Step by step printing
Print the odd-pages PDF. Take the printed stack, turn it over according to your printer's paper path, and put it back into the tray. Then print the even-pages PDF from Keep Even Pages. If the backs come out in reverse order, reverse the even pages with Organize PDF and try again.
Common problems and how to fix them
Back pages are upside down: rotate the stack 180° before feeding it, or try once with two sheets to learn your printer. The last back page is missing: with an odd number of pages, the last sheet has no back — that is normal. Scanned odd and even pages need to be combined: merge the two files and use Organize PDF to interleave them.
Good habits
Test with a short document first, mark the top edge of the stack with a pencil, and keep the complete original PDF.