Question 1

Why is rasterized redaction safer than drawing visual black boxes?

Accepted Answer

Naive redaction tools often overlay a black visual box on top of the text while leaving the underlying text stream or vector glyphs intact. Anyone can copy the hidden text or delete the rectangle in a PDF viewer. Ambiakshi paints opaque rectangles directly onto canvas bitmaps and re-encodes each page as a flattened image, permanently destroying the original characters underneath.

Question 2

Why can't I search or select text on my PDF pages after redacting?

Accepted Answer

To ensure that blacked-out information cannot be recovered under any circumstance, the entire page is flattened into a high-resolution bitmap image before being re-compiled into a PDF. Consequently, all text on that page—not just the redacted area—becomes image pixels and will no longer be selectable or searchable with Ctrl+F / Cmd+F.

Question 3

Does redacting a PDF strip hidden metadata and edit history?

Accepted Answer

Yes. Many PDF data leaks occur through document properties, author tags, prior revision streams, and form field entries. Ambiakshi constructs a brand-new PDF file from the flattened page images, stripping original document metadata, embedded XML streams, modification timestamps, and hidden annotations.

Question 4

How should I verify that my PAN, Aadhaar, or financial details were safely removed?

Accepted Answer

After downloading your redacted PDF, always open it in a reader (like Chrome, Preview, or Acrobat) before sharing. Attempt to highlight and copy text across the blackened areas, and perform a Ctrl+F (or Cmd+F) search for your PAN, Aadhaar number, or name to confirm that zero matches exist in the file.

Question 5

Are my sensitive documents uploaded to a server during redaction?

Accepted Answer

No. All PDF decoding, canvas drawing, blackout rendering, and rasterized PDF assembly execute 100% locally in your browser's memory using Canvas 2D and client-side JavaScript. No document content, images, or metadata are ever transmitted across the network.

Question 6

What are the recommended file size and page count limits for redaction?

Accepted Answer

Because rendering pages to high-resolution canvas elements requires client RAM, we recommend documents up to 50 MB or approximately 50 pages for smooth performance. For larger files, consider splitting the document first or redacting only the sensitive pages to prevent browser tab memory exhaustion.

Black out private info in a PDF

Flattened blackout, not forensic erasure

Frequently asked

Feedback, bugs & custom requests

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