An illustration of a typical result. No real file, name or location is used.
Before — what you would be sending
proposal-v7.pdfPDF
Authora.whitfield
Earlier versions retainedSaved 4 times — earlier drafts still in the file
Comments and annotations3 found
After cleaning
proposal-v7-clean.pdfPDF
Authorremoved
Earlier versions retainedremoved
Comments and annotationsremoved
Page content and layout are untouched. Only the metadata fields are blanked.
The information dictionary
Every PDF has a small structure holding Author, Title, Subject, Keywords, Creator and Producer, plus creation and modification timestamps. The author field is usually filled in automatically from the account name on the machine that made it. Nobody sets it deliberately, and almost nobody checks it.
Incremental saves keep the past
PDFs can be updated by appending changes to the end of the file rather than rewriting it. The original content stays where it was. A file saved this way several times contains its own earlier versions, and text that was edited out can often be recovered from it. You can spot this: the marker that ends a PDF appears more than once.
Redaction boxes that are only boxes
Drawing a black rectangle over text in a PDF viewer adds a rectangle. It does not delete the text underneath, which stays selectable and copyable. This has produced real disclosures in court filings and published government reports. True redaction removes the content and then flattens the document.
What else can be hiding in there
PDFs can carry embedded JavaScript, attached files, actions that ask to launch a program, and reviewer comments left in as annotations. This page reports all of them.
In practice
Counting the end markers yourself
A PDF finishes with the five characters %%EOF. A file saved once contains that marker once. Every incremental save appends a new section ending in another one. Open the PDF in a plain text editor — it will look like nonsense, which is expected — and search for %%EOF. If you find three, you are looking at three generations of the document, and the first two are still in there. This takes about thirty seconds and needs no tools.
Flattening a document properly
The reliable way to collapse a PDF's history is to print it to a new PDF rather than editing the existing one. On macOS this is in the print dialog under PDF, Save as PDF. On Windows, choose Microsoft Print to PDF as the printer. The output is a fresh document built from the rendered pages, with no earlier states and no accumulated metadata. It also flattens form fields and annotations, which is usually what you want when sending a final version.
Why the author field is so often wrong
The field is filled in automatically from the operating system account name of whoever created the source document. That means it frequently names someone who is not the author at all: the colleague whose template was reused, the assistant who set up the file, or an old account name from a machine replaced years ago. It is worth checking not only because it discloses a name, but because the name it discloses may be misleading in a way that matters.
Common questions
Does a PDF contain the author's name?
Usually. The author field is typically populated automatically from the user account of the computer that created it.
Can deleted text be recovered from a PDF?
If the file was saved incrementally, often yes. Earlier versions of the content remain in the file.
How do I properly redact a PDF?
Remove the content itself rather than covering it, then flatten or re-export the document. Covering text with a shape leaves it fully readable.