PDF Changer

Visual Redaction

Draw redaction boxes on pages and burn them irreversibly by rasterizing.

Category: Privacy
Processing: On-device
Quota bucket: Heavy
Open interactive tool: /tools/redact

How to use Visual Redaction

  1. Load a PDF and wait for page thumbnails to render.
  2. Click a page to open the full-size redaction canvas at 200 DPI.
  3. Click and drag to draw red rectangles over content to redact. Click an existing rectangle to remove it.
  4. Review ALL pages — redacted pages show red overlays, but every page gets rasterized on burn.
  5. Click Burn Redactions. This is permanent and irreversible. The output replaces every page with a flat image.

Tips

  • Every page is rasterized at 200 DPI on burn, not just pages with redactions. This prevents metadata analysis from revealing which pages were redacted.
  • Draw rectangles slightly larger than the target content. Rasterization at 200 DPI can shift pixel boundaries by 1-2px.
  • After burning, open the output PDF, zoom to 200%, and verify each redacted area is fully black. This is the critical verification step.
  • Output file size will be larger than the original. A 10-page document at 200 DPI produces roughly 5-15MB depending on content complexity.
  • For maximum privacy, run the Paranoid Scrub after redaction to strip any remaining metadata from the rasterized output.
Privacy: Your files never leave your browser. All processing runs on-device. Full privacy model

Frequently asked questions

What does Visual Redaction change?

It rasterizes every page at 200 DPI, draws solid black rectangles over marked areas, and exports the result as image-only pages. The original text, fonts, layers, and metadata are destroyed. This is not a cosmetic overlay — the content is gone.

Is Visual Redaction private by default?

All processing happens locally in your browser. No document data is uploaded. The redaction canvas renders pages using PDF.js, the same library used by Firefox.

What does Visual Redaction not protect?

Output is image-only — no selectable text. File size increases to 0.5-1.5MB per page. The 200-page cap exists because each page requires ~50MB of RAM for rasterization.

Limitations

  • Redaction is irreversible by design. There is no undo after burning. The original text under redacted areas is destroyed, not hidden.
  • Output file size increases significantly because every page becomes a raster image. Expect 0.5-1.5MB per page at 200 DPI.
  • Text in the output PDF is not selectable. If recipients need searchable text, they would need to OCR the result.
  • Documents over 200 pages are capped for browser memory safety. Split first, then redact sections individually.
  • This is visual redaction only. It does not produce PDF redaction annotations compatible with Adobe's redaction workflow.

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Documentation