Comparing signed PDF documents

Each time a person digitally signs a PDF document that already has one signature, Acrobat saves the changes and signature of each subsequent signatory in a special appended version of the file. You can then compare the various versions to note what changes, if any, each signatory made.
Acrobat notes when a PDF document that you’ve sent out for subsequent signatures comes back to you with changes by adding a Document Was Modified item to the Signatures palette. You can then display the details of the modifications by clicking the Expand button (with the plus sign on Windows and the triangle pointing to the right on the Mac). Note that the detailed change items shown in the expanded list are purely informational and do not perform as bookmarks.
To have Acrobat do a side-by-side comparison of the versions to let you visually compare the changes, select View Signed Version on the Signatures palette Options pop-up menu. Acrobat then displays the original version of the PDF file and the most current version in a Document pane. To compare the files side by side, choose Window➪Tile➪Vertically. You can then scroll through the pages, visually noting the differences. When you’re finished checking the changes, close the original version on the left by clicking its document window’s Close button and maximize the latest version on the right by clicking its document window’s Maximize button. If you would prefer, you can have Acrobat do a page-by-page comparison and locate all the changes between the latest signed version and the original. To do this, select Compare Signed Version to Current Document on the Signatures palette Options pop-up menu. Acrobat then performs a page-by-page comparison and creates a second PDF document containing only the pages that have changed. These changed pages are displayed side by side. When you have finished comparing these pages, you can close this newly created document by pressing Ctrl+W (Ô+W). You can then save it in its own PDF file by clicking the Yes button in the alert dialog box that asks you if you want to save the changes before closing. If you have no further need for this comparison PDF file, you can click the No button to abandon the comparison document and just return to the most up-to-date signed version of the PDF document.