1 Reply Latest reply on Jan 25, 2017 1:25 PM by Adorobat

    Why does Remove Hidden Information and Sanitize Document cause file size to increase 2-10x?


      Using book-scanning services, I have books scanned into pdf files as 300dpi images. Using Acrobat DC Pro, I run the Recognize Text tool within the Enhance Scans category (which actually decreases the file size). I then, within the Redact category, try to Remove Hidden Information or Sanitize Document, and the file size explodes upward. As a representative example, this is what happens:

      Step 0: Book as received from scanning service: 19MB

      Step 1: Book after running text recognition: 13MB

      Step 2: Book after running Remove Hidden Information: 53MB

      or: Step 2: Book after running Sanitize Document: 22MB


      Incredibly, not only does the file size increase dramatically when removing information/sanitizing document, but, to put salt on the wounds, the image quality also decreases noticeably! This always happens, with no exception.


      1) Why does this happen? Intuitively, I would think removing hidden information would actually reduce file size, especially if the image quality deteriorates.


      2) Is there any solution to this?


      3) Assuming there is no good built-in Acrobat solution, is there any third-party software alternative to sanitize pdf documents that doesn't cause file size to explode up?