PDF Accessibility

Key Points to Consider

Not all PDF documents are Accessible and may require adjustment to their details and structure. It is usually easier to to many of these steps in the initial source document, however if it is not available, the required steps are outlined in the following PDF Accessibility Workflow.

Note: Many changes made to the document during the Accessibility testing workflow are not reversible. It is advisable to work on a copy of the file until all changes are complete. Remember to save regularly once key steps have been completed.

PDF Accessibility Workflow

You will need access to Adobe Acrobat Professional to remediate a file. This workflow relates to Acrobat versions X & XI. Earlier versions may have different labelling.

1. Check if OCR is needed

Try selecting text from the file or searching for a sample of content text. If text cannot be recognised or searched, the file is an image and needs to have OCR run.

Convert the image based files using OCR

View > Tools > Recognise Text
Select document options from the toolbar. Output to ClearScan at 600dpi

2. Document Settings

Set Language for the document

File > Properties > Advanced > Language  > English

Complete Document Properties including title, description and keywords

File > Properties > Description

Set to show document title

File > Properties > Initial View > Show > Document Title

Save file.

3. Check if Document is Tagged

Access the file Properties and check the 'Description' pane for tagging status.

If the document is not tagged add them

View > Tools >Accessibility > Add tags to document

4. Check Reading Order

This is not always accurate and will impact on the reading order used by Screen Readers and how the document will reflow for smaller screens.

Select the 'Order' tools from the left Acrobat menu - this will open a listing each page and its tagged components. You can re-arrange the order of items by clicking and dragging them into a new location. Items can also be deleted

Open the 'TouchUp Reading Order' pane found under the Accessibility Tools on the right of the Acrobat window. The TouchUp tool enables you to change the type of content to provide a suitable semantic structure to the document or remove them from the flow completely. Select areas of the PDF document and when they are highlighted select the appropriate tag for that item.

  • Hide redundant images or artefacts Image > Background
  • Are headings in a logical order eg. H1 for page title, H2 for chapter headings etc
  • Add ALT text to images to provide suitable descriptions. Select image > Edit Alt Text
  • Rearrange order in the Show Order Panel. Click and drag components
  • Use Table Editor to adjust tables and include heading information

You can clear the reading order for a page and begin again from scratch - this is sometimes the easiest option.

5. Check Links

Access the 'Tags' tool from the left Acrobat menu. From the drop-down dialogue at the top select 'Find'.

Find > Unmarked Links > Search Document 
Add a 'Link' tag where necessary

6. Forms

Acrobat should detect and form fields used in the document but a verification of the results will be required.

Forms can be quite difficult to repair and the easiest approach is often to adjust the source document and reconvert to PDF or delete the form fields from the PDF and add them in again.

7. Tagging

This is the content and structure accessed by Screen Readers so its critical it is correct.

The more effort you put into your source document (usually Word) structure the less work you will have to do in this step.

Open the Tags pane. Explode out the various layers and check for:

  • Empty tags/Artefacts
  • Tables
  • Heading order

Tags can be changed through the 'properties' dialogue. Select the relevant tag and right click. In the dialogue choose the appropriate tag under the 'Tag' tab.

8. Other Structure

Add bookmarks to provide a table of contents.

Bookmarks > New Bookmarks from Structure

Select the tags to provide structure eg. H1, H2, H3 and add a title for the bookmarks list eg. 'Contents'

9. Run Full Accessibility Check

From the Accessibility pane select 'Full Check'. If there are errors they will be displayed in the Acrobat pane on the left. The Accessibility check may need to be run several times to resolve all issues.

Sometimes the errors returned are not helpful or do not make sense such as an image alt being required when there are no images in the file. The Troubleshooting PDF page has examples to some common issues and solutions.

10. Test in Alternate Checker

Adobe does not check against all the necessary criteria. As a final step test your document in an alternate checker to see if there are any final adjustments to be made.

Typical points Adobe does NOT check for include:

  • Bookmarks
  • H1 first heading in document
  • Heading Structure
  • Heading Order
  • Table Headings
  • Document Title

11. Test in Screen Reader

To understand how your document is accessed by a Screen Reader you can test your document in Read Out Loud.

View > Read Out Loud > Activate Read Out Loud

You can chose to read a single page or whole document.

While this step is not necessary for every document it is particularly important if the file has a complex layout that includes tables or forms.