PDFs are practical, but they also pose significant accessibility challenges for blind and visually impaired individuals. Here we will show you how to make your PDFs more accessible.

Making an existing PDF accessible

Adobe Acrobat offers the best accessibility tools, for example for adding alternative text. However, the set-up differs greatly from one version of the program to the other. We therefore recommend that you identify your version and search for the appropriate instructions online.

PDF from a scanned text

Scanning text from a book or journal usually creates an image PDF. For a screen reader to be able to read the text, you should take the following steps.

Use a professional book scanner (in the university library, for example) and select the following settings:

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• Scan format PDF (not image)
• Page separation
• Remove fingers
• Highest resolution possible
• Grayscale

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This will produce an image PDF. This must now be converted into a text PDF using “Optical Character Recognition” (OCR). Different versions of Adobe Acrobat offer this function, for example:

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• Adobe Acrobat PRO 2017: Tools > Optimize Scanned PDF
• Adobe Acrobat 9 Pro: Document > OCR Text Recognition

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OCR will convert the image PDF into an MS Word document. You can then follow the instructions in Chapters 4 to 6 to make it accessible and save it again as a PDF. Besides Adobe Acrobat, there are other programs with good OCR functionality, such as ABBYY Fine Reader or Foxit. These are fee-based, but you can download a demo version and work with it for several days.

A free alternative is the excellent open-source software “tesseract”. Unfortunately, it is difficult to use because it does not have a graphic interface, which means it has to be managed from the terminal. MacOS users can install the software with Homebrew or MacPorts, and tesseract is also available in most GNU/Linus distributions.

More information is available at https://tesseract-ocr.github.io8.