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PDF Files are Image-Based

PDF files can be created in multiple ways. In the past, you might have used an optical scanner to read a paper document and create an image file which would then be converted to PDF. The resulting PDF file would not be readable by a screen reader user. Fortunately, more recent scanners allow you to select optical character recognition (OCR) or text mode which allows you scan a paper document and create a text-based PDF file.


Standard

Example of Standard in Action

If you find that your PDF file is image-based, then you can:

  • Rescan the physical document using OCR as mentioned above.
  • Recreate the file digitally with editing software.
  • Use the Adobe Acrobat Professional IX tool which has a feature to convert scanned text to real text. To convert the document, select Tools in the right-hand column, then select Recognize Text. The quality of the text depends on the quality of the source document. The conversion is usually fairly good, but you should probably clean up the document by selecting Find All Suspects in the Recognize Text submenu.

Example of Issue

In order to test whether your PDF file is an image or text-based file, use the highlight test.

  • Place your cursor at the beginning of a line of text.
  • With your mouse or keyboard, try to highlight the text.
  • Inability to highlight the text indicates that the text area is an object and not text.

PDF Image vs text

Locating the Issue in Your Course

You will want to look through your course for each instance of a PDF. You can click through each page in your course to look for PDFs, or use the file management tools within your LMS.   In order to test whether your PDF file is an image or text-based file, use the highlight test

  • Place your cursor at the beginning of a line of text.
  • With your mouse or keyboard, try to highlight the text.
  • Inability to highlight the text indicates that the text area is an object and not text.

Resources to Align With Standard

  • WebAIM (Web Accessibility in Mind) provides web accessibility solutions to individuals with disabilities. Links provided will give you information about the different types of visual impairments, such as blindness, colorblindness and low vision and how to make the web more accessible to users with visual disabilities.
  • IT Accessibility at the University of Illinois is about making it possible for users to access, consume and interact with digital media while maintaining content, message and purpose.

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