everyday mac tools

Replace a page in a PDF on a Mac, such as a signed page

· 6 min read

To replace a page in a PDF on a Mac, open a copy of the PDF in Preview, show the thumbnails, insert the new page next to the old one with Edit, Insert, Page from File, then select the old page and press Delete. Work on a copy, because Preview saves your changes into whichever file you opened.

The usual reason is a signed page. You printed page 7 of an agreement, signed it, scanned it, and now need it back in place of the unsigned version without reprinting the whole thing. The same steps work for a corrected page from a revised draft.

Get the new page into a PDF first

The replacement has to exist as a file Preview can insert. How you get there depends on where it came from.

  • A page from another PDF. Nothing to prepare. Preview can take it straight from that file, including a single page from a longer one (see below).
  • A scanner. Save the scan as a PDF if the scanner software offers the choice.
  • An iPhone. Scan rather than photograph. In Preview, choose File, Import from iPhone or iPad, Scan Documents, and the iPhone’s camera opens in scanning mode. The page arrives in Preview cropped and flattened.
  • A photo you already took. Open it in Preview and choose File, Export as PDF. Turning phone photos of a document into one readable PDF covers straightening and cleaning up a photographed page first.
  • A document from a word processor. Choose File, Print, open the PDF menu at the bottom of the print dialog, and choose Save as PDF.

Scan at the same paper size as the original where you can. Preview keeps every page at its own size, so a page scanned at A4 inside a Letter-sized document will look slightly off when the pages are viewed side by side or printed.

Replace the page in Preview

  1. In Finder, select the original PDF and choose File, Duplicate. Work on the copy. Preview writes changes back into the file you have open, and while File, Revert To can often undo that, a copy is simpler and certain.
  2. Open the copy in Preview and choose View, Thumbnails, so every page shows in the sidebar.
  3. Click the thumbnail of the page you are replacing.
  4. Choose Edit, Insert, Page from File, and pick the file with the new page. It is inserted directly after the page you selected.
  5. Click the old page’s thumbnail again and press Delete.
  6. Scroll through the thumbnails and check that the new page sits where the old one was, the right way up. If it is sideways, select it and choose Tools, Rotate Left or Rotate Right.
  7. Choose File, Save.

If the new page lives inside a multi-page PDF, Page from File brings in every page of that file. To take just one, open that PDF in its own Preview window with thumbnails showing, and drag the page you need from its sidebar into the sidebar of your copy, dropping it where it belongs. Then delete the old page as above. Merge PDFs on a Mac covers moving pages between files in more detail, and fix a scanned PDF that is sideways and out of order helps if the order goes wrong.

Check what else changed

Swapping a page is simple. A few side effects are worth a look before you send the file.

The signed page is an image. A scanned page carries no text layer, so it cannot be searched and its text cannot be selected or read aloud by a screen reader. The rest of the document is unaffected. If that matters for whoever receives it, make a scanned PDF searchable adds the text layer back.

The file got bigger. One page scanned at high resolution can outweigh the rest of the document together. If the result is too large to email, compress a PDF without wrecking the scans shows how to bring it down without making the signature illegible.

A digital signature breaks. If the original carried a certificate-based digital signature, as opposed to a drawn or scanned one, changing any page invalidates it. That is the signature doing its job, since it exists to show the document has not changed since signing. Ask for it to be signed again after the swap.

Metadata comes along. The finished file still carries the original’s title, author and creating application. Usually that is fine. If it is not, remove metadata from a PDF before you send it.

Doing it without touching the original

The trap in this job is Preview’s habit of saving into the file you opened, which is why the first step is making a copy. If you swap pages in agreements or case files often, it helps to use a tool that never edits the original at all.

Basalt is a native Mac PDF app where every tool writes a new file and the original is never modified. For a page swap, Images to PDF turns a photographed page into a PDF, Merge brings it into the document, and Organise deletes the old page and puts the new one in its place. Make Searchable adds a text layer to the scanned page, and Compare lets you check the new version against the original so you can confirm the only change is the page you meant to swap. Documents are opened by a separate engine process that has no network access, so an agreement never leaves the Mac. Basalt is free for 24 hours with every tool, then a $29 lifetime license for up to three Macs.

Questions

Does replacing a page change the page count? Not if you insert the new page and delete the old one. The count only changes if the file you insert from has more than one page and you keep the extras.

Why is the new page a different size from the others? It was scanned or exported at a different paper size. Preview keeps each page’s own dimensions. Rescan at the original’s size if it matters, for example for printing.

Can I undo the replacement after saving? If you worked on a copy, the original is untouched. If you edited the original, File, Revert To, Browse All Versions in Preview can often bring back an earlier state.