How to create accessible PDFs
Most PDFs are not accessible
PDF files are not automatically accessible. Since some PDFs are scanned images, those PDFs need to have optical character recognition (OCR) performed to make each line of text selectable. When the text is selectable it can be highlighted or read by text-to-speech software. A PDF that has selectable text can still be missing a tag structure. The tag structure is what conveys to assistive technologies like screen reading software how the elements should be read on a given page.
Sharing Content
If the content is already available as a web page, Canvas page, or Microsoft Word Document, then a PDF document is probably not needed. An accessible PDF takes time and effort to create. Before creating a PDF, consider if it is worth it. Also, students with learning disabilities such as dyslexia may find a PDF more difficult to access. This is because it is more challenging to adjust the font style than a Word Document. A student using screen reading software and an older PDF reader application may encounter accessibility issues even if the PDF is accessible. This is why it is recommended to provide the content in multiple formats like an accessible Word Document and accessible PDF file if possible.
PDFs created with Microsoft Word
Microsoft Word provides an accessibility checker and the ability to add heading levels to a document. This makes it easy to create an accessible Microsoft Word Document. A Microsoft Word Document can be saved as an accessible PDF file. When saving the document, make sure that the option “best for electronic distribution and accessibility” is selected. Check out the tutorial video Creating An Accessible PDF File Using Microsoft Word for more information.
Scanned PDFs
When generating a PDF by scanning documents, ensure that the original documents are easily readable. Pages with dark gutters or those that are skewed will not be compatible with assistive technologies. When a PDF is created by scanning pages of text, an image PDF is usually generated. An image PDF is the most inaccessible type of PDF because it lacks optical character recognition and a tag structure.
How to check if your PDF file is an image PDF
- In a PDF reader application like Adobe Acrobat or Apple’s Preview, select text. This can be done by highlighting some text with the mouse or going to the edit menu and choosing Select All. Alternatively, the keyboard shortcut: Cmd-A on a Mac or Ctrl-A on a PC can be used to select all the text in the PDF.
- Copy the selected text and paste it into a document. If no text is copied over or the text appears garbled, then optical character recognition has not been applied. If all the text copies over and the read order is preserved, then the PDF is not an image PDF.
Use SCRIBE
An image-based PDF or a PDF that lacks a consistent tag structure can be inaccessible. It is recommended to use SCRIBE to remediate an inaccessible PDF. SCRIBE will perform optical character recognition and may provide the document with a heading structure. The SCRIBE-generated PDF will be more accessible than the image-based PDF and will be compatible with text-to-speech software. However, SCRIBE will not add alt text for images, does not tag tables, and may miss headings. When using SCRIBE, it is recommended to choose the PDF (image over text) option. Canvas also has a SCRIBE integration that is available for immediate use. If you have questions regarding SCRIBE, reach out to rlcole@stanford.edu.
Use Equidox to create a fully accessible PDF
Equidox is a PDF remediation platform that allows the user to generate a fully accessible PDF. The author must take the time to manually tag their PDF. This requires marking any headings, lists, links, and tables. The platform makes it easy to add alt text for images too. Equidox will then generate an accessible PDF that will be compatible with text-to-speech and screen reading software.