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Redacting a PDF: local blackouts versus real redaction

How browser-based PDF redaction (a solid black visual block) differs from Adobe's Mark as Redacted, and which one to use for scans and text PDFs.

Before sending out a contract, a quote or a copy of an ID document, you usually have to cover up an ID number, an amount or a signature. Tools like Smallpdf can do it, but the file has to be uploaded first — and for confidential drafts I would rather keep it local.

Dragging out redactions with TwoThink

Open Redact PDF:

  1. Drop in the PDF (a single file up to 50MB)
  2. Preview the current page and drag out a rectangle
  3. Turn the pages and keep redacting; you can redact a whole page or delete a single area
  4. Export and download the PDF with the black blocks

Everything is processed locally in the browser, with no upload.

A visual blackout is not the same as deleting the text

This tool draws a solid black rectangle over the area, so nothing is visible. But the text objects inside the PDF usually remain, and professional software or a script may still extract them.

If you need to remove the sensitive text for good (a compliance-grade "Mark as Redacted"), use software that supports real redaction, such as Adobe Acrobat Pro.

MethodVisible to the eyeProtects against copying / extraction
This tool (black block)✅ Invisible❌ Not guaranteed
Acrobat Mark as Redacted✅✅ Removes the content stream

Scans versus text PDFs

  • Text PDFs: the block covers it visually, but the text layer may still be there — mind the extraction risk
  • Scans / image pages: they were images to begin with, so after redaction there is only a black block and no copyable text layer at all

Can I export the mosaic effect?

No. Mosaic and blur are there to make the preview easier to check; the export is always a solid black block, so the redaction looks the same when printed or forwarded.

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