PDF has been a popular format to share documents. However, it is much easier to make the original document (in Word or PowerPoint) accessible than making the PDF version of the document accessible. The Goverment Digital Service is recommending to publish content in HTML rather than PDF to improve accessibility.
We recommend making the original document accessible and available. Only if this is not possible, consider sharing an accessible PDF.
Create an accessible PDF
It is always a good practice to make the original document accessible and then convert it to a PDF. You may find guides on creating accessible documents and accessible presentations useful. Whenever possible share the document in its original format.
Unfortunately, Adobe Illustrator does not allow exporting a tagged, accessible PDF. There is a request for this feature since 2017 at Illustrator's User Voice forum. Illustrator created PDFs have to be manually tagged to make accessible.
Using Acrobat Pro to remediate content
This guide will look at common issues reported by PDF Accessibility Checker (requires Adobe Acrobat Pro version) and how to remediate them. This paid-for software allows editing a PDF.
Tools tab under Protect & Standardise you can add Accessibility. This will then appear on the right hand side panel (View > Tools > Accessibility). Select Accessibility Check.
Title - Failed
Check your original document to see whether you have provided a title under File > Info > Properties > Title
If you have already provided a document title, the issue could be caused by an incorrect setting. In your PDF document go to File > Properties > Initial View tab > Window Options > Show: from the dropdown select Document Title > OK. Now run the Accessibility Check again and this error should be resolved.
Logical Reading order - Needs manual check
Right click on left margin and selecting "Accessibility tags" to add the Tags pane to the left hand margin. Click on Tags. This will display the accessibility tags tree for the document.
If your document tags tree shows "No tags available", this means the document is not created with accessibility tags. There are two options available to make this document accessible. First and the recommended option is to go back to the original document and export it with accessibility tags. The second option is to manually tag the document, which take time, effort and technical knowledge.
Expand the tag tree. On an element if you press right arrow key it open that tag and left arrow will close it. Walk down the tag tree to see whether the content on the page appears in the correct order. If not you can drag and drop the elements to correct the order.
Character encoding - Failed
If you have the original document, it is always desirable to go back to that document andchange the font and re-export the PDF. If you do not have the original document, use editing tools to re-encode the file. Follow the video Fixing the Character Encoding Failed Error from 2mins 10s. to fix the error.
Note: We have noticed Character encoding error with ligatures when using Effra font (ff, fl, fi, ti, ft and so on). In some design software packages ligatures can be turned off using options. How to turn off ligatures in Illustrator
How to turn off ligatures in InDesign
Navigation links - Needs manual check
Each link in the document should be clicked on manually to see whether they are working correctly. If not, the link needs to be corrected.
Field description - Failed
This issue arises when form fields are missing alternative text. Go to Tools > Prepare Form to remediate these issues. Now go to the form field > right click > Properties. Make sure the two properties Name and Tooltip contains meaningful information. For example, if the form field was named Job title you could add the same for both Name and Tooltip. Missing tool tip causes the error "Field description - Failed". Now run the Accessibility Check again and this error should be resolved.
Figures alternate text - Failed
This error appears when there are images without alternative text. Clicking on the error will list the figures where the error applies. In the original document provide alternative text or mark the image as decorative as appropriate.
Headers - Failed
This error appears when table headers are not defined. In the original document mark the table headers as appropriate.
In Word, select the table go to Table Design. If the first row contains headers select the checkbox Header Row. If the first column contains the headers select First Column.
To remediate this in a PDF, follow the steps shown in the video Fix PDF Accessibility Issue: Headers - Failed
Regularity - Failed
When there are complex tables and the PDF is created using Acrobat > Create PDF this error appears. In the original document remove merged and or split cells to create a simple table structure. If you require a complex table structure, making it accessible will take considerable manual effort. Follow the steps in Accessible PDF Tables under Correcting Complex Tables to make a complex table fully accessible.
Appropriate nesting - Failed
This issue arises when the heading hierarchy is not correctly applied. Headings should not miss a heading level. That is H1, H2, H3 and so on should be followed in order. For example, if there is H1 and the next heading is H3 this error will appear in the PDF accessibility checker.
Do not use the built in Title style in Word as this is not associated to a heading level and when Title style is followed by H2 in a document Word Accessibility Check does not show an error (as of May 2023). But once converted to PDF, this gives an error. Therefore, make sure to use H1, H2, H3 and so on appropriately in your document.
Alternative description missing for annotation
Select the LINK tag right click and select Properties. Add alternate text in the Alternate Text field.