PDF “Best Practices” for Content Creation

Ken Petri

OSU Web Accessibility Center

Screen reader accessible and printable version

When to Use PDF

Very long, complexly footnoted documents
To preserve visual layout (multiple columns, etc.)
Documents designed for print
Complex math (because MathML is limited)
If legally restricted (example, tax forms)

When to Use PDF (cont.)

In most other cases use HTML in preference to PDF

Accessibility of PDF

Platforms Supporting PDF
- Windows via Acrobat/Acrobat Reader, GSView (others?)
- Mac OS X natively via Preview
- Linux/Unix via Acrobat Reader, Ghostview, OpenOffice, KPDF
- Both Pocket PC and Palm devices via various readers
Screen Reader Access
- JAWS, Window-Eyes, and IBM Home Page Reader on Windows
- VoiceOver and Preview on Mac OS X Tiger
- Linux: KTTS? Gnopernicus? Orca?

PDF is very widely supported. Virtually all platforms have a readily available reader. The status of screen reader support is not as clear. The major screen reading programs on Windows and VoiceOver on Mac do a good job reading PDF. On Linux, there are a number of screen reader projects. We have not tested them yet. We have seen mention online of Gnopernicus working well with PDF. KTTS is the text-to-speech system for the KDE desktop. It is designed to work with KDE desktop applications; however, the developer roadmap shows that KPDF is currently not working with KTTS. One of the most promissing Linux accessibility projects is Orca. It is aimed at the GNOME desktop and is currently being developed by Sun Microsystems. For more on Linux and assistive technologies, check out Sun Accessibility Architect Peter Korn's Blog.

Accessibility of PDF (cont.)

Screen Reader Access within Web Pages
- In IE only and then with marginal success
- Best to open "externally" in Acrobat Reader (more on this at end of presentation)

Checking PDF for Accessibility

Get Document Properties
- File → Document Properties, check if Tagged PDF
Try selecting some text
- Can it be selected?
Try enlarging the text
- Does it scale without distorting too much?
Try linearizing the document
- View → Reflow
- Is the reading order acceptable?
Let Acrobat read it for you
- View → Read Out Loud

Checking PDF for Accessibility (cont.)

Run built-in accessibility test: Advanced → Accessibility
Acid Test: "View" the PDF with a screen reader
- See WAC overview of Screen Readers for download and other information (http://wac.osu.edu/resources/at.html#screen-readers)

"Types" of PDF

Images of text: inaccessible and unindexable
Untagged PDF
- Screen reader will start Acrobat's process for automatic tagging
- Auto-tagging results are often poor due to lack of structure of original document
- Auto-tagged documents almost always requires manual touch-up (can be painful, more later)
Tagged and well-structured PDF is the goal

Depending on its settings, Acrobat Professional will attempt to run optical character recognition on PDFs that have been originally created by scanning an image of text. We have seen very good results from this process. In terms of accessibility, however, this cannot be counted on. First, Acrobat Reader, the web browser plugin and stand-alone program most users will have on their systems, does not have the OCR functionality. Second, this post-processing does not created tagged PDF.

In many configurations, viewing a PDF while a screen reading program is running will launch the auto-tagging feature within Acrobat and Acrobat Reader. Tagging is the process of marking up the text within a PDF document and applying to it a structure that a screen reading program can understand. This tagging should be done when the PDF is created (more on this later). If it is not done when the PDF is created, Acrobat and Acrobat Reader will try to automatically generate a tag structure for the PDF. Auto-tagging often results in poorly marked up PDF that is non-optimal for screen readers.

The best strategy for accessible PDF is to use PDF Maker to generate a solid tag structure from inside a well-laid out Microsoft Word document. We cover this below.

Retrofitting Bad PDF

Were PDFs authored before Acrobat version 5.0 (2001)? If so, they are untagged, at best
Strategies for retrofitting
- Find the original text/Word document and re-PDF
- OCR, dictate, or retype, if original is an image
- Automatically tag with manual touch-up (time consuming!)

Creating Accessible PDF from Word

Don't
- Don't print to "Adoble PDF"
- Don't use tabs or spaces for alignment or formatting
- Don't style text divisions by changing font size and weight
Do
- Do use PDFMaker to export to PDF
- Do use styles
- Do create headings
- Do caption and make alternative text for images
- Do create real lists, columns, and tables
- Do consider TOC and TOF

Steps for PDF from Word

Check if PDF Maker Plugin is active
- Help → About: Disabled Items

Making Good Use of Word

Use built in or custom styles for all basic formatting. No tabbing or font-size adjustments to make "headings", returns to make line breaks between paragraphs, etc.

You can open MS Word's style menu in a pane in the right-hand side of the Word window. Either click on the icon depicting two "A"s to the left of the styles pull down menu or, from the main menu, Format → Styles and Formatting....



Use the Styles and Formatting menu for all text formatting. Doing so will not only save you time and make the appearance of Word documents more consistent, it will also go a long way toward helping create well-structured and accessible PDFs.


One immediately visible benefit comes from using headings in the Styles and Formatting menu. Headings inserted or formatted from that menu become structure when you create a Table of Contents within Word and become bookmarks in the bookmark panel when you output PDF using PDF Maker.




  Add Text Alternatives
  
    For inserted images or figures, create well thought out text alternatives
    Right-click, Format picture, enter text on Web tab
      
      
    
  


Text alternatives are read by screen reading programs and provide essential information for blind and low-vision users. You can think of text alternatives for images as the equivalent of "ALT" text for images in web pages.





  Captioning and Tables of Contents
  
    Captioning of figures and tables
    
      Select object, Insert → Reference → Caption
    
    
    Creating tables of contents or tables of figures
    
      Insert page break at start of document (good time to create a title page, as well)
      Tables of contents are generated from headings, figures from captions
      Insert → Reference → Indexes and Tables → use either Table of Contents or Table of Figures tab
      
      
    
  


Created this way in MS Word, when exported via PDF Maker, the table of contents in the PDF is hyperlinked, so that clicking any entry in it will take you to that section in the PDF. This and the bookmarks pane help greatly with navigation for screen reader users and persons with mobility impairments.





  Captioning (cont.)
  
    Note that the caption must be implemented as a "frame" rather than a text box
    
      To convert, Format → Text Box, "Text Box" tab, "Convert to Frame" button 
      
    
  


The caption on a table or graphic can appear either above, below, or to the side of the image. It won't appear in the table of figures, however, until you convert the caption text box to a frame, as illustrated above.





  Converting from Word to PDF
  
    Click the "Convert to Adobe PDF" button
    
    
  



  Troubleshooting PDF
  
    Basic check for tagged PDF
    File → Document Properties, Tagged: Yes

    

    Check read order for multi-column documents
    View → Zoom → Reflow
    
    Set a tab order
    Pages tab, select a page, Page Properties, Tab Order tab, select Use Document Structure
    
    Bookmarks can be manually created from the Bookmarks tab. To make sure it shows by default, choose File → Document Properties → Initial View → Show → Bookmarks Panel and Page
  




  Accessibility Menu
      
        Advanced → Accessibilty: Touchup Reading Order to guarantee read order
        
          You can remove items from the order
   After conversion, tables will almost always need to be touched-up using the "Table Inspector"
   
   Create header rows for your tables. Avoid tables with row or columns spanning multiple cells 
 
  
  
  
  



  Accessibility Menu (cont.)
  
  Run accessibility checks, Full Check being the most useful
  
        



  Fine Tuning PDF
  
    To set properties for any tagged element (figure, bit of text), open the Tags pane (View → Navigation Panels → Tags) select the element, right-click, Properties
    Once common example would be setting alternative text or the language for text
  
    



  Security Settings and Accessibility
  
    Password Security settings: Secure → Show Security Settings
    
    Enable copying for low security documents
    For high security, "Enable Text Access For Screen Reader Devices For The Visually Impaired" in the Password Security Settings dialog box. 
  
  
  



  Accessible PDF Forms
  
    Has fillable form fields
    Form fields are described for screen readers and give mouseover tool tip
    Has a logical tab order set
    Fully tagged
    If long, could have bookmark structure for easy navigation




  Accessible PDF Forms (cont.)
  
    Use LiveCycle Designer for complex forms or documents that are mainly forms
  
    To start LiveCycle in Acrobat 8: Forms → Create new form...
  
  
  Use Acrobat for simple forms that are occasional in longer documents
  
    To edit forms within Acrobat: Forms → Edit form in Acrobat
    Right-click field, Properties. Use "Tooltip" for the screen reader text to be read
  
  
  



Accessible PDF Forms (cont.)

  Use simple field descriptions ("Custom screen reader text"): "Last Name" is better than "Type in your last name"

  



Accessible PDF Forms (cont.)

Set a tab order for fields

  Use Tools → Advanced Editing: Touch-up Reading Order







  OpenOffice Writer and PDF
  
    Native export of PDF
    Good support for basic form creation
    Excellent export options
    Caveat: You will almost certainly have to touch up the document reading order.
  



  OpenOffice Writer and PDF
  Export options in OpenOffice allow you to tag PDF and control how PDF's display when they first launch.
  



  HTML Alternatives to PDF
  
    Text documents and presentations are generally more accessible as well-structured HTML
    
      Convert PowerPoint and Word to HTML with the Illinois Accessible Web Publishing Wizard (Note: Wizard does not support Office 2007)
      For those with knowledge of HTML, Eric Meyer's s5 is a presentation alternative
    
    
  


As mentioned earlier in this presentation, there are specific use cases for PDF. If your document is going to be on the web and does not fall into one of those use cases, well structured HTML is generally a more accessible format than PDF. 


For a definitive overview of when to use PDF and discussion of its relative accessibility, see Joe Clark's Facts and Opinions About PDF Accessibility. WebAIM also has an excellent discussion and tutorial on PDF Accessibilty.





  Linking Strategies (Within Carmen)
  
    Since you can't tell Carmen to force a document to open in an external program, you must announce the type of the document in the link text. Use a parenthetical descriptor:
    
      my hyperlink to document (MS Word) or
my hyperlink to document (PDF)
      
    
    
    IE will try to open Word and PDF within the browser window. Other browsers on Windows will open Word in its native application. PDF will load into the browser window, though you can set it in Firefox to open in the native application.
    
      In Firefox: Tools → Options → File Types: Manage. Set PDF to open in the external application, rather than using the browser plugin.
    
    
  



  Linking Strategies (cont.)
  
    We have had extremely poor results with screen readers reading PDF inside browsers other than IE. And even in Internet Explorer results are mixed.
    JAWS and other screen readers can be set to always open Word, PDF, PowerPoint, etc. in the application. But this is a setting users may not know about.