PDF metadata checker

Where a PDF keeps its metadata

• Document information dictionary: Author, Title, Subject, Keywords, Creator (the app it was made in), Producer (what wrote the PDF), and created and modified dates.
• XMP packet: an XML block that often repeats the author and adds the creating tool, document IDs and an edit history. Pages and images can have their own.
• Earlier revisions: when a PDF is saved incrementally, changes are appended to the end and the original contents stay in the file^[1]. The checker counts these revisions.

What cleaning does

The cleaned copy has no document information dictionary and no XMP on the document, its pages or its images. It is written as a single revision, and objects that nothing refers to any more are dropped, so earlier versions don't come along. The checker then reads the cleaned copy again and lists anything left.

It does not change what you see: text, images, links, annotations, form fields and attachments stay as they are. Annotations and attachments are reported so you can decide about them in a PDF editor.

Password-protected PDFs

If a PDF is encrypted, some fields can't be read and cleaning is turned off. Remove the password in the app that created the file, then check it again.

This is not redaction

Drawing a black box over text in a PDF hides it on screen but leaves the text underneath. Removing metadata does not change that. Use a redaction tool that deletes the underlying content, then check the result here for leftover properties and revisions.