Glossary
Redaction
Also called: redacting
Redaction is the permanent removal of information from a copy of a document before it is disclosed, leaving the original intact. Done properly the removed content cannot be recovered from the released file, which is precisely where most redaction failures occur.
Redaction explained
The failure mode
A black rectangle drawn over text in a PDF is an annotation sitting on top of the text layer. The text is still in the file, still selectable, still extractable, and it has been recovered from published documents by journalists and researchers repeatedly. The same applies to changing text colour to white, or covering it with an image.
Proper redaction removes the underlying content from the released copy and flattens the result, so there is nothing left to recover.
Original and released copy
Redaction always produces a new document. The unredacted original is retained — you will need it if the redaction is challenged on review or appeal — and the released copy is the one that circulates. Systems that redact in place destroy evidence.
Where the obligation arises
Freedom of information and public records responses, litigation disclosure, subject access requests where third-party data must be removed, and any publication of a document containing personal or commercially confidential information. In each case the reasoning behind a redaction should be recorded, because an internal review or appeal will ask for it.
Practical process
Work on a copy, apply redactions destructively, flatten the output, then verify by extracting text from the released file and confirming the removed content is absent. That verification step takes seconds and is the one that catches the annotation-not-redaction mistake.
Recording the reasoning
Each redaction should carry the exemption or ground relied on. An internal review will ask, and a released document with unexplained gaps invites an appeal.
FAQ
Redaction: common questions
Can redaction be automated?
Detection can be assisted — patterns like national insurance numbers and card numbers are findable automatically. The decision to redact is a judgement about exemptions and should be made and recorded by a person.
Should the original be deleted after redaction?
No. Retain it. If the redaction is challenged, you need the original to demonstrate what was withheld and why.
Related terms
- Audit trailAn audit trail is an append-only record of every action taken on a document — views, downloads, edits, approvals, permission changes and deletions — with the acting user, timestamp and affected version.
- Chain of custodyChain of custody is the documented, unbroken record of who has held, accessed or altered an item of evidence, and when.
- DispositionDisposition is what happens to a record when its retention period expires: destruction, transfer to an archive, or a decision to extend.
- Document controlDocument control is the discipline of ensuring only approved documents are in use, superseded ones cannot be mistaken for current, and every change is authorised and recorded.
- Information governanceInformation governance is the framework of accountability, policies and controls determining how an organisation creates, uses, retains and disposes of its information.
- Legal holdA legal hold suspends the routine destruction of records that may be relevant to litigation, an investigation or an audit.
Zuletzt geprüft: 28. August 2026. Browse the full glossary.