Why scanned PDFs are harder to redact than digital ones

A scanned page can contain both an image and an OCR text layer. Adding a display-only black box does not establish that both have been handled.

PrivScrub rebuilds every output page as an image, removing searchable and accessible text from all pages. Unboxed areas retain their visible appearance. Check that regions fully cover the visible sensitive content, then review every page in the actual output.

Automatically recognizing text in a scan needs an image-recognition step such as OCR. PrivScrub's current output workflow does not run OCR; read the image manually or use an appropriate separate recognition workflow and review its results.

OCR introduces recognition errors (0/O, 1/l confusion), so automated detection on scans is less reliable than on digital text and needs more human review.

Many scanned reports and receipts carry a QR or barcode that often encodes a sensitive identifier like a visit or order number.

They exist as images, so text detection can't see them — remember to cover these graphics during redaction too.

For supported files, fully cover sensitive regions, including QR codes. Prefer solid fills for sensitive text and inspect the actual output.

PII checks cover extractable or pasted text only. Sensitive content in images needs visual review, and external OCR results can contain recognition errors.

PDF editing supports basic, unencrypted files up to 50 pages and 25 MiB. Nonempty annotations, internal or external links, forms, attachments, actions and layers are unsupported and stop processing before export. Redaction rebuilds every page as an image, removing searchable and accessible text from all pages. Metadata removal retains supported page content. Output checks reread the actual file, cover only listed items, and do not run OCR. Visually review every output page.