Accessible PDF files are tagged. These tags, similar to styles in Word documents, tell a screen reader how to interpret the various elements of the file. I will address two types of PDF files:
- Text files that have been created in Word (or similar program) and converted to PDF.
- Files that you have scanned and saved to PDF.
For files created in a program such as Word and converted to PDF, if you have you have followed accessibility guidelines for creating that document (e.g. accessible Word documents and accessible PowerPoint files), the accessibility features will be retained in the PDF file. A basic guide for converting files to accessible PDFs is available from WebAIM.
If you did not create the original file and do not know whether accessibility has been incorporated, you can use Adobe Acrobat to evaluate and improve the accessibility of PDF files.
If you scan a hard-copy document such as a journal article, chapter from a book, etc. an image will be created. This image will not be readable for screenreaders. For students using the screen reader, the page will effectively be blank. To avoid this unreadable image, the document should be scanned using text recognition. The quality of the text recognition will depend on the quality of the hard-copy document. Once the document has been scanned as text, you can make necessary corrections to the text and add tags for accessibility.