Reveal old PDF metadata

[obetz]

Hi all,

AFAIK, ExifTool only appends PDF metadata, the old metadata stays in the document but is inactive.

How can I read the previous metadata after such a change (assuming that I didn't re-linearize the PDF)?

Or completely revert the change done by ExifTool?

[StarGeek]

From the PDF Tags page

If ExifTool was used to modify a PDF file, the original may be recovered by deleting the PDF-update pseudo-group (with -PDF-update:all= on the command line).

This is the link I keep handy to describe the incremental update. "Incremental Updates in PDF files", Debenu Foxit

Phil has said in the past that exiftool can only remove updates it has made, not those made by other programs if they also use incremental updates.

[obetz]

Thanks, "incremental update" is the description I was missing.

[obetz]

the search for suitable tools resulted in a few hits

https://blog.didierstevens.com/programs/pdf-tools/ -> pdftool.py "can check if a PDF contains incremental updates, and select the versions you want"

Code Select Expand

pdftool.py iu source.pdf lists all incremental updates

Code Select Expand

pdftool.py -d -s 2 -o out.pdf iu source.pdf extracts version 2

There is also a Java tool "Multivalent" on Sourceforge, but the author removed the "undo" part a few years ago.

[StarGeek]

Oh, nice. A new tool for the toolkit.