Blacken PDF - how to make text passages unrecognizable

To make individual text passages, sentences or entire pages in a PDF file unrecognizable, you can blacken them. There is a function for this in Adobe Acrobat as well as in the free alternatives to the program. Get an overview of how to do this correctly.

How to blacken your PDF with Adobe Acrobat

If your PDF file contains individual passages that you want to make unrecognizable, this is possible by using the content blackening feature. Please note, however, that this feature is only available if you use the paid Pro version of Adobe Acrobat.

1. First, open the document you want to redact in Adobe Acrobat and switch to the "Display" tab.
2. Navigate there to "Tools" > "Protection" and click on the right margin on the option "Blacken and remove content".
3. Then mark the text to be blackened and select one of the three methods "Highlight text for blackening", "Blacken entire page" or "Search for a term or pattern and blacken all occurring".
4. Finally confirm that the content to be blackened should really be removed permanently and save the file under a new name.

These other programs for blackening a PDF file are available

Alternatively to the use of the paid Pro version of Acrobat, the blackening of text passages is also feasible with free programs such as the "PDFCreator" or the "PDF Xchange Viewer". There, under "Tools" > "Annotations", simply select the "Rectangle" option and set black as the color for the fill to paint over the text to be blackened with it.