Moving comments onto a revised PDF in PDF by Zaweba
Comment > Migrate comments moves comments from an earlier version onto the revised file, each following its own words, even when they moved page.
Documents change while they are being reviewed. You comment on version one, the author sends version two with a page added at the front, and suddenly every comment you made is on the wrong spot if you copy it across. Importing comments by position cannot cope with text that has moved.
PDF by Zaweba solves this with Comment > Migrate comments from an earlier version. It moves the comments of an earlier file onto the open revised one, each following its words, even onto another page. Comments whose words were deleted stay where they were, and the status line tells you how many.
How it works
Rather than copying comments by their position on the page, migration looks at the words each comment is attached to. In the revised file, it finds those words and places the comment there. If a paragraph has moved down half a page, the highlight moves with it. If a section has moved to a different page, the comment follows to that page.
That is what makes it useful for real revisions. Authors add paragraphs, reorder sections and insert pages. Positions change; words mostly do not.
When words have gone
Sometimes the author deletes the text a comment was about, often because the comment asked for it to go. Migration cannot follow words that no longer exist, so those comments stay where they were on the page, and the status line says how many there are.
That count is useful in itself. Go through those comments and check them. Often they are proposals that were accepted, and you can set their status to show it.
A good routine
Open the revised file. Choose Comment > Migrate comments from an earlier version and pick the earlier file. When it finishes, note the count in the status line.
Then open the Comments panel and sort by page. Work through the comments to check each one against the new text. For a comment that asked for a change, see whether the change was made and set its status. For a comment whose words were deleted, decide whether the deletion settled it.
Save the revised file with its comments under a clear name, so you have a record of which comments were carried forward.
Why it matters for reviews
Without migration, a reviewer has to compare two versions by eye and re-make comments, which is slow and easy to get wrong. With it, the second round of review starts where the first left off, and checking whether each point was handled becomes a matter of going down a list.
It pairs naturally with proposed text changes. A reviewer proposes replacements in round one; after migration, the author and reviewer can see in round two which proposals were taken up.
How it fits with other comment tools
Importing XFDF, FDF or another PDF's comments brings comments in by position, which is right when the pages have not changed. Migration is for when they have. The Comments panel, statuses and review history then help you track what happened to each point.
Limits to keep in mind
Migration needs real text in both files. A scan has no words to follow until the text is recognised.
Heavy rewrites reduce how much can be matched. If a paragraph has been completely rewritten, its comments have nothing to follow and will stay put, adding to the count.
For ordinary revisions, though, migration in PDF by Zaweba saves hours and keeps every comment attached to what it was really about.
