PDF metadata
How to remove metadata from a PDF
Besides its pages, a PDF keeps notes about itself: who wrote it, with which programs, when it was made and changed — and often the version it was before the last edit. hexscope shows them and saves a copy without them, in your browser. The file is not uploaded anywhere.
1 What a PDF's metadata holds
- Document properties: the title, the author, the subject and keywords, the program the document was written in, the one that made the PDF, and when it was created and last changed.
- XMP: the same again in another block, often with a history of the steps that made the file.
- Earlier versions. A PDF edited and saved again often keeps what it was before, with what the edit took off the page. See Deleted from a PDF, but still inside it.
- Comments and the names of their authors, and the EXIF of every photo on its pages: where each was taken, with which camera.
Open the sample edited PDF: its author is Olena Koval, and an earlier version still inside it says “Salary: 4,200 EUR a month”.
2 Remove it
Open the PDF in hexscope. Under What this document reveals, press Remove it — save a clean copy. The PDF is written anew in your browser:
- without its properties and XMP, and without its earlier versions;
- with the camera data taken out of its photos;
- with the text under black boxes, and text no one can see, taken out letter by letter, and marks for redaction applied.
Then press Open the clean copy. hexscope reads the copy back and says, for each thing it found, that it is gone: the author, the title, the subject, the keywords, the programs, the dates and the history.
3 Other ways, and their catches
- Adobe Acrobat Pro: Sanitize Document (under Redact) removes metadata, hidden text, comments and earlier versions. Changing the fields in File → Properties only overwrites what the properties show; the XMP and earlier versions may still say the old.
- ExifTool: its PDF edits are added as a new version, so the old metadata stays in the file, and can be brought back. Rewrite the file afterwards (for example with qpdf) for the old to go.
- Print to PDF makes a new file, but it names the program that printed it and the time you printed.
4 Many PDFs at once
Drop a folder of PDFs on the page, or choose several: each is listed with what it gives away, and Save clean copies saves the clean ones as a ZIP. For a website or a repository, the command line and GitHub Action do the same before anything is published.
Check a PDF now Your files never leave your browser.