What to do when weird characters appear in PDF files

by Laura Silva, Marketing Program Manager


Occasionally, you may open a PDF file to find that it displays and/or prints strange symbols or unintelligible characters. It can happen only on certain PDF files opened in one PDF reader or editor, or it can happen in some files in every PDF reader or editor you try using.

PDF files have been known to do even more bizarre things using the wrong characters. In an extreme case, one user reported that characters were swapped throughout a PDF document. For example, the word and punctuation “Abstract:” was being consistently replaced with “\9)A%:*A2”. And text for the phrase “The first one” was being replaced with “!”# F(%)A $;#”.

In this case, there was a pattern to the mix-up. The letter “t” was being consistently changed to “A” while “#” was taking the place of “e”. Not only did it make the document unreadable, but it also affected searching, too. If they wanted to search for “Abstract:”, they needed to type in “\9)A%:*A2” in order to find it.

The above example is indeed extreme and difficult to reproduce, yet it often leads back to the same issue. While there are a number of reasons situations like these happen, they often occur when a PDF file doesn’t have the fonts that are used in the original document embedded within it. That means that Foxit Reader, PhantomPDF and any other PDF reader or PDF editing software will use their default fonts instead of the document’s fonts.

These issues can often be resolved by the original document author creating a new PDF file in which the original fonts are embedded. If that’s not possible, however, you can try a couple of things yourself.

  • Use the “Print As Image” feature. Sometimes, printing the document shows the correct characters even when they aren’t viewable on screen. Your document will be printed as an image on paper and you may be able to read it that way. If it works, you can OCR it to create a digital file that’s readable and searchable.
  • Convert to Word and back to PDF. Another option you can try is to convert the PDF file into a Word document and then convert it to a PDF file again. Here’s how.
    1. Go to File > Export > To MS Office > Word
    2. Under Settings, choose Image-based document
    3. Choose Set Languages
    4. In the pop-up box, select the source language and tap OK to set it
    5. Hit OKConvert to Word

If neither of these workarounds are successful, you may need to contact the original author of the PDF file to determine what the problem is.

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