Sometimes, for instance to get a printing arrangement right, it’s useful to be able to insert blank pages into a PDF file. cpdf can add blank pages before a given page or pages, or after. The pages in question are specified by a range in the usual way:
cpdf -pad-before in.pdf 1 -o out.pdf
Add a blank page before page 1 (i.e. at the beginning of the document.)
cpdf -pad-after in.pdf 2,16,38,84,121,147 -o out.pdf
Add a blank page after pages 2, 16, 38, 84, 121 and 147 (for instance, to add a clean page between chapters of a document.)
The dimensions of the padded page are derived from the boxes (media box, crop box etc.) of the page after or before which the padding is to be applied.
The -pad-every n operation places a blank page after every n pages, excluding any last one. For example…
cpdf -pad-every 3 in.pdf -o out.pdf
Add a blank page after every three pages
…on a 9 page document adds a blank page after pages 3 and 6.
The -pad-multiple n operation adds blank pages so the document has a multiple of n pages. For example:
cpdf -pad-multiple 8 in.pdf -o out.pdf
Add blank pages to in.pdf so it has a multiple of 8 pages.