Prevent PDF file size increase after redaction

Sanitizing a PDF increases the file size

When you sanitize a PDF document or remove hidden information, you may notice the following changes in the document:

  • The PDF is rasterized, and so you can’t edit the PDF.
  • The size of the PDF document is increased.

These changes occur because Acrobat removes the overlapping content from the document by default. To prevent these changes, you need to retain the overlapping content in the PDF while sanitizing the document. 

Enabling the preference to retain overlapping content while sanitizing PDF (Acrobat and Acrobat 2020)

  1. In Acrobat, go to Edit > Preferences (Windows), or Acrobat > Preferences (macOS). 

  2. In the Categories on the left, choose Documents

  3. In the Hidden Information section, select Do not remove overlapping content while Sanitizing document (this might leave some hidden information), and then click OK

    Preference to not remove overlapping content while sanitizing the document

Retaining overlapping content while removing hidden information using redaction in Acrobat 2020

  1. Open the PDF in Acrobat 2020 and mark the text or images you want to redact, and then click Apply.

    Mark the text or images you want to redact, and then click Apply

  2. Acrobat prompts if you want to permanently remove the content marked for redaction. Click OK

    To remove the redacted content, click OK

  3. Acrobat prompts you to view and remove additional hidden information. Click Yes.

    Remove hidden information

  4. From the Remove Hidden information pane on the left, deselect the Overlapping Objects option, and then click Remove.


    In Acrobat, click Sanitize Documents. Next, choose selectively remove hidden information, and then deselect the Overlapping Objects option.

    Deselect the remove overlapping objects option


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