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This script will take two existing PDF files and interleave (collate) their pages into a new file, so that the pages from the first document will become the odd pages (1,3,5,7...) and the pages from the second document will become the even pages (2,4,6,8...) of the new file.
New Feature: It is now also possible to merge a file containing odd pages in ascending order (1,3,5,7...) with a file containing even pages in descending order (8,6,4,2...). This is particularly useful if you scan a stack of pages, turn then over and then scan the reverse side in the opposite order.
For more information about this tool, you can contact me directly.