Adobe’s Portable Document Format (PDF) is widely used in distributing documents on campus. It is possible to make most PDF files accessible for users with disabilities, but it is generally much easier to make HTML web pages accessible, and HTML is more widely supported by assistive technologies. Also, certain content (such as mathematical and scientific notation) can not currently be made accessible in PDF files. Therefore, the first consideration related to PDF accessibility must always be this:
Is PDF necessary for my document, or could I communicate the same information using an HTML web page?
If your answer to the above question is "Yes, PDF is necessary", it is important to follow certain steps in order to create a PDF that is accessible. It is also possible to correct accessibility problems post-production using Adobe Acrobat Professional. This page contains workflows for both situations.
Making a PDF Accessible from Scratch
- Use authoring tools that support accessible tagged PDF (e.g., Microsoft Word in Windows)
- Follow best practices for authoring documents that are accessible:
- Use built-in styles for headings
- Add alt text to images (in Office 2010 and 2011 use Description field; not Title)
- For data tables, explicitly identify the header row (in Word, do this in Table Properties)
- Export to Tagged PDF (see below)
Exporting from Word to Tagged PDF
- In Word 2003 and 2007 (Windows), this requires the Adobe PDFMaker Plugin (this ships with Adobe Acrobat).
- In Word 2010 (Windows), simply "Save As PDF". (NOTE: Word 2011 for Mac does not produce an accessible tagged PDF).
- When saving, select Options and be sure that "Document structure tags for accessibility" is checked. (NOTE: This is checked by default, but will be unchecked if you select "Minimize Size" and will need to be re-checked.
Creating an Accessible Tagged PDF from Adobe InDesign
The following steps apply to InDesign CS5.5. Documents created using CS4 and earlier versions of InDesign require accessibility repair using Adobe Acrobat Pro (see the next section).
- Create your document using paragraph styles (Window > Styles > Paragraph Styles). These aren’t just a good idea—they’re required for accessibility. Use them consistently throughout the document to define styles for all text, including headings and sub-headings. For headings, use styles that indicate the heading level (e.g., Heading1, Heading2) within the organizational structure of the document (headings should form an outline of the document).
- Associate each of the styles you’ve created with specific PDF tags. From the Paragraph Styles options menu, select Edit All Export Tags, check the PDF radio button, then select the relevant tags for each of your styles.
- Add alt text to images (Object > Object Export Options > Alt Text).
- Establish content read order with the Articles panel (Window > Articles). Simply drag content from the document into the Articles panel in the order in which it should be read by screen readers. To drag multiple items, select them in the correct read order using Shift+click, then drag them all at once to the Articles panel.
- Export to PDF, and be sure to select “Acrobat 6″ or higher for Compatibility, and check the “Create Tagged PDF” checkbox.
There are additional details about each of these steps, plus a few others, in Adobe’s white paper New Solutions for Creating Accessible PDF Documents with Adobe InDesign CS5.5 (in PDF). There are additional resources available on the Adobe InDesign CS5.5 Accessibility website.
PDF Document Accessibility Repair Workflow (using Adobe Acrobat Pro)
NOTE: Modifying PDFs can have unpredictable results, and there is no "Undo". Save often! (Saving multiple versions is recommended)
- Does document have text?
- If no, covert to text (View > Tools > Recognize Text)
- Is document tagged? (Ctrl+D, "Description" tab)
- If no, add tags (View > Tools > Accessibility > Add Tags To Document)
- Does document need to be "touched up"? (View > Tools > Accessibility > Touch Up Reading Order)
- Click decorative or redundant images, then click "background"
- Add alt text to remaining images (right click on image, "Edit alt text")
- Rearrange order if needed (click "Show order panel", drag items)
- Are headings marked up as headings at appropriate levels?
- Determine visually what the heading structure should be
- View > Show/Hide > Navigation Panes > Tags
- Use PDF text selector to highlight headings
- In Tag pane, select "Find Tag from Selection"
- To change tag, right click, select Properties, enter Alternate Text
- Does other markup need to be fixed?
- Delete tag and start over from scratch????
- Are URLs encoded as links?
- If not, Tools > Document Processing > Create Links from URLs
- Is the language of the document defined?
- File > Properties > Advanced > Language
- Check for any lingering errors
- Tools > Accessibility > Full check
PDF Form Accessibility Repair Workflow (using Adobe Acrobat Pro)
- 1. Is form interactive?
- If no, proceed to Creating Accessible PDF Forms using Acrobat Pro
- Is tab order intuitive?
- If no, correct it (Tools > Forms > Edit, play with Tab Order; select "Close Form Editing" when finished)
- Are all text fields appropriately labeled? How to tell:
- Tools > Forms > Edit; look in Properties for ToolTip of each field, or
- Tab through form using Read Out Loud (View > Read Out Loud > Activate Read Out Loud)
- To fix labels on text fields:
- Right click on field; select Properties
- Enter a detailed, easy-to-understand prompt as Tooltip
- Are radio buttons appropriately grouped and labeled?
- All radio buttons in a set should have the same name
- Tooltip is the overall prompt for the set (similar to legend in HTML)
- Labels for individual radio buttons within the set are defined using the Button Value field in the Options tab
- Are checkboxes appropriately labeled?
- Checkboxes can’t be grouped like radio buttons. The workaround is to be sure the prompt for the overall set of checkboxes is clear within the tooltip for each option (for example, "Favorite Food: Tofu", "Favorite Food: Steak", "Favorite Food: Pizza", etc.)
- Finishing touches
- Tools > Document Processing > Create Links from URLs
- Tools > Accessibility > Add Tags To Document
- Repair tags as needed
- Tools > Accessibility > Full Check
Creating Accessible PDF Forms using Adobe Acrobat Pro
- Do not create an interactive form using the original authoring tools’ form features
- Do not create a tagged PDF
- Use Acrobat Pro to make form fields interactive. Here’s how:
- Automatically detect & markup form fields (Tools > Forms > Create)
- Manually add/edit and form fields that weren’t correctly detected
- Check tab order; repair if needed
- Check all labels (tooltips); repair if needed
- Check group labels and options for radio buttons; repair if needed
- Check labels for checkboxes; repair if needed
Creating Accessible PDF Forms using Adobe LiveCycle Designer
Some people prefer using LiveCycle Designer for creating PDF forms. It is fairly easy and intuitive, and has many more features for creating robust interactive forms. The pros and cons of each are beyond the scope of this document, but there are other sources for this information, including Adobe’s Acrobat versus LiveCycle Designer.
If you choose to create forms using LiveCycle Designer, here are some things to keep in mind related to accessibility:
- Tags in LiveCycle Designer forms cannot be edited using Adobe Acrobat Pro.
- LiveCycle Designer’s built-in templates should not be used. They include untagged inaccessible content that cannot be corrected.
- The Basic Workflow:
- Start with a blank document
- Drag form fields and other content as needed into the document
- Be sure to include a tooltip for all fields
- LiveCycle Designer additionally has an option for "Custom Screen Reader Text". Screen readers won’t read both this text and the tooltip, so if you use both be sure they stand alone.
- Save as PDF