How to permanently remove text from a PDF
- Find the exact wording
Open the document in the reader and search for the term. Redaction matches what is in the text layer, character for character.
- List every variant
'A. Student', 'Student, A' and '[email protected]' are three different strings. Miss one and it stays.
- Redact
Each match is covered with a black box and its characters are deleted from the file.
- Verify the result yourself
Open it, search for the term, and try to select the black boxes. This step is not optional.
Why this matters for exam and study documents
Sharing a marked script with a study group means removing your name and candidate number first. Cropping or covering them does not do that. This does.
What is kept, what changes, and what this will not do
The difference between what a tool prevents and what it merely requests matters more here than anywhere else on the site, so each one states which it is.
Kept
- Everything you did not name
- Page count, order and layout
Changed
- The listed text is deleted from the file and covered with a black box
- Text positions around a redaction are not reflowed
- The document's text layer no longer contains the removed characters
Limits
- Only text in the text layer can be redacted. A scanned page has none, and the tool refuses rather than producing a file that looks redacted and is not.
- Matching is exact and case-sensitive.
- Identifying information in the file's metadata is separate - check that too.
Questions and answers
How is this different from drawing a black box?
A black box is a drawing on top of text that is still there. Select underneath it and you have the text back. Redaction deletes the characters, so there is nothing underneath to recover.
Can I redact a scanned document?
No, and the tool will tell you so rather than appearing to work. A scan has no text layer to search, so the words are part of an image. Crop the region out instead, or cover it before scanning.
How do I know it worked?
Open the result, search for the term, and try to select the black area. If the search finds nothing and the selection is empty, the text is gone. Always check - this is the one operation where 'it looked fine' is not good enough.
Does this remove my name from the file's properties?
No. Metadata is stored separately from page content. Check the document properties as well, and use Flatten PDF or a metadata-clearing rebuild if a name is sitting in the author field.