NCDAE Tips and Tools: Adobe Acrobat & PDF

Created: April 2006

This document is intended as a discussion of the accessibility of Adobe Acrobat PDF.

We will add to this page based on any comments we receive. We are most interested in ways in which users have increased accessibility through the use of tools or workarounds that enhance PDF accessibility for individuals with disabilities.

Description

After HTML, PDF (Portable Document Format) files are probably the most common files on the Web. PDF is usually used when a file needs to appear or print a certain way, regardless of the browser or technology.

PDF files can be made accessible to people with disabilities, although usually with more difficulty than with HTML. A key part of this process involves creating tags that make a document more accessible to screen reader users.

Product Website

For more information on Acrobat Pro, visit http://www.adobe.com/products/acrobatpro/main.html
For a 30 day trial of Acrobat Pro, visit http://www.adobe.com/products/acrobatpro/tryout.html

PDF Tags

PDF tags are a text-only representation of the PDF file which is presented to screen readers instead of the original file. They exist for accessibility purposes only and have no visible effect on the PDF file. HTML tags and PDF tags often use similar tag names and organization structures, but they really are quite different. For one thing, it is impossible to insert PDF tags in a "code" view like you can with HTML. Still, if you are comfortable with HTML you will probably have an easier time creating and editing tagged PDF files.

Increasing PDF Accessibility

There are 3 main ways to increase the accessibility of a PDF file.

Create a natively accessible file in a Microsoft Office program (usually Word) or Adobe program (usually InDesign) and export as tagged PDF.
Create and edit a tagged PDF using Adobe Acrobat Pro.
Leverage the accessibility of Adobe Reader.

Export to PDF in Word or InDesign

Although there are countless programs that can be used to export a Word document to PDF format, there are a very small number of programs that can save Word documents as properly tagged PDF files. Of these, Adobe Acrobat is the most reliable A document with complex tables or forms will probably need to have the tagging process completed in Acrobat.

In summary, it is possible to convert a Word or InDesign document into a properly tagged PDF if you can verify the following.

The document has been appropriately tagged.
The document is exported to PDF using a program that creates tagged PDF, probably a recent version of Adobe Acrobat.
The PDF is correctly tagged.

Create and edit a tagged PDF in Acrobat Professional

Note: This resource was created using Acrobat 7 Professional for Windows. Some of the features, techniques and commands mentioned may be different in other versions of Acrobat. Although there are several versions of Acrobat and several utilities that can convert files to PDF, Acrobat Professional is required to edit a tagged PDF.

Tags tab

You can view, reorder, rename, modify, delete and create tags within the Tags tab panel. To view the tags tab, select View > Navigation Tabs > Tags. You will want to leave this panel open the entire time you are editing a tagged PDF. Most of the work of editing tags is accomplished through the use of the tags tab and the Options menu in the upper corner of the Tags tab. The following table lists how to accomplish several common tasks.

Task	From the "Options"
Highlight the content in the document that corresponds to a selected tag	Check Highlight Content
Find a tag from selected text, image, etc.	Find Tag From Selection
Create a tag for selected content from the document	Create Tag From Selection
Change a tag	First select the tag, then choose Properties > Tag > Type
Add tags to an untagged document	If all tags have been deleted, select Add Tags to Document

TouchUp Reading Order pane

The TouchUp Reading Order offers a fast way to tag a PDF. Not everything can be tagged using this tool, but it extremely helpful. To use the TouchUp Reading Order tool, select Advanced > Accessibility > TouchUp Reading Order. This tool is mentioned several times in the following table.

Accessibility challenges within Adobe Acrobat

Accessibility challenge	Disability type(s)	Solution(s)
Only true headings and lists will convey semantic meaning to a screen reader user.	Blind	Tag all headings so they are true headings. Use the TouchUp Reading Order tool. Tag all lists as ordered or unordered lists.
Images must include an alternative description (alt text) to be meaningful to a screen reader user.	Blind	Right-click on the selected image and select Properties from the menu. Click on the Tag tab and type the appropriate alt text in the field labeled Alternate Text. While in TouchUp Reading Order, Right-click on the image and choose Edit Alternate Text.
Complex charts or tables may not contain proper headings, captions or summaries.	Blind	Use the tags tab designated table rows (<TR>), table headers (<TH>), and table data cells (<TD>). If you have a document with multiple tables that need to be tagged, consider deleting all the tags and then re-tagging the untagged file.
Poor color contrast, especially in images and charts.	Color blind, Low vision	Ensure sufficient color contrast in text, charts and images. One way to verify this is to print out the document on a black and white printer.
Documents with forms that can be filled in on the screen (checkboxes, text fields, etc.) may not be accessible to screen reader users and may not export correctly to other formats.	Blind, all users	Make sure form elements have appropriate tags. Verify that the form can be completed using common screen readers.
A page may be read out of order by a screen reader. That is, the reading order and the visual order may be different.	Blind	Check and edit the reading order using the reading order tab (View > Navigation Tabs > Order). You can use this panel to change the reading order of the content without altering the visual layout of the page.
Scanned PDF files that are not converted to plain text will not be accessible to screen reader users.	Blind	Convert a scanned PDF file into text using an Optical Character Recognition program.
A PDF reader program must be used to view PDF files.	All users	The Adobe Reader can be downloaded free from the Adobe site. There are a number of free reader programs that are available for several platforms. The accessibility features of these readers vary.
Embedded multimedia may be inaccessible, especially if it is not captioned.	Deaf, Blind	Make sure embedded multimedia is captioned. This is possible in a PDF file. If necessary, provide audio descriptions for the blind.
Scanned PDF files converted to real text can have numerous misspellings that may only be apparent to screen reader users.	Blind	Use a spell check to make sure as many words are spelled correctly as possible.
Headers, footers, logos and other content that meant to be ignored may be read by a screen reader on every page.	Blind	Convert extraneous information to an artifact (Select tag > Options in the Tags tab > Change tag to artifact). If appropriate, make the first instance of repetitive information visible and convert subsequent versions into artifacts.

Adobe Reader

Adobe Reader is not the only tool available to read PDF files, but it does contain several tools that can be used to increase the accessibility of a PDF file. You cannot assume that any of these features will be used to compensate for an inaccessible PDF. The following table lists some accessibility solutions available in Adobe Reader.

Accessibility challenge	Disability type(s)	Solution(s)
Poor color contrast between text and the background.	Color blind, Low vision	Change the default color for the text and/or background. Select Edit > Preferences > Accessibility from the menu on the left side of the window. If you check the box labeled Replace Document Colors you then have several options for color schemes.
PDF files usually open in a browser. Accessibility is usually enhanced when Adobe Reader opens outside of the browser.	All users	Change the default behavior of Adobe Reader, so that PDF files do not open in the browser. Select Edit > Preferences > Internet from the menu on the left side of the window and de-select Display PDF in browser.
An enlarged document may not be visible without horizontal and vertical scrolling.	Low vision, all users	Enable reflow (View > Reflow or Ctrl + 4).
Continually scrolling a document can be very tedious.	Motor	Enable Automatic Scrolling (View > Automatically Scroll or press Ctrl + Shift + H). The speed of the scrolling can be changed with the up and down arrows.
An older screen reader may not support a certain PDF file.	Blind	If the file contains real text, try the Read Out Loud Feature. It is like a light-weight screen reader. To enable the Read Out Loud feature, Select View > Read Out Loud.

Accessibility Setup Assistant

The Accessibility Setup Assistant allows the user to change many preferences of Acrobat reader in one place. This feature is available in Reader 7. To run the setup assistant choose Help > Accessibility Setup Assistant....

Additional resources

WebAIM article on Acrobat and PDF accessibility
Creating Accessible Documents with Adobe Acrobat 7.0- PDF. From the Adobe site
A List Apart: Facts and Opinions About PDF Accessibility. By Joe Clark

Links to VPAT

A Voluntary Product Accessibility Template (VPAT) is a vendor-generated table that describes to what extent a product complies with Section 508 of the Rehabilitation Act. It follows a template created by The Information Technology Industry Council (ITI).

The VPAT for Adobe Acrobat is available at: http://www.adobe.com/products/server/pdfs/LiveCycleDoctSec70_508.pdf (PDF format)
PDF format documentation is available at: http://partners.adobe.com/public/developer/pdf/index_reference.html

Comments

The National Center on Disability and Access to Education invites comments on this fact sheet. We would like to add accessibility workarounds that others have found useful, as well as add links to important resources. Please contact the author with questions, comments or suggestions.

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