What is accessibility?

Accessibility enables individuals with disabilities — such as people with blindness, low vision, or mobility impairments — to read, hear, and interact with computer-based information and content with or without the aid of assistive technology.

A document is considered accessible if its contents can be accessed by anyone, not just by people who can see well and use a mouse.

For instance, people with low vision or blindness may rely on screen magnification software, screen reader software that converts text to speech or Braille output, or other assistive technology to present the contents of a document that they want to read. For these people, visual indicators of a document's structure — such as different font sizes to distinguish headings — may not be easy to follow. An accessible document has built-in information that enables assistive technology to interpret the document's structure and to present the information in a logical reading order.

Similarly, people with mobility impairments may require an alternative keyboard, an alternative pointing device, or voice input software to navigate the document. They may be able to see a document but be unable to use a mouse to position a text insertion point to fill in a form field. An accessible document for these people has support for keyboard navigation, as well as a preset tab order that makes moving from field to field in a form easier.

Accessible Adobe PDF documents tend to benefit all users because the underlying document structure that enables a screen reader to properly read a PDF document aloud also enables a handheld device to correctly display the document. Similarly, the preset tab order of an accessible PDF form helps all users, not just users with mobility impairments, complete the form more easily.

What makes an Adobe PDF document accessible?

Adobe PDF (Portable Document Format) is a standard on the World Wide Web and is also used to distribute electronic documents over corporate networks, by e-mail, and on digital media. All accessible Adobe PDF documents have the following five characteristics.

1. A logical structure and reading order

   For assistive tools and assistive technology to read an accessible PDF document effectively, the document must have an underlying, logical structure and reading order. This logical structure and reading order utilize built-in, behind-the-scenes elements called tags, which a PDF author adds to the document and optimizes for accessibility.

   In an accessible PDF document, tags perform two functions: They depict the hierarchy of content — such as text blocks, headings, sidebars, and other page elements — and they define the intended reading order of the content on each page. Assistive tools rely on these tags to present text in a way that makes sense when someone is hearing the text read out loud or reading it on-screen in an alternative viewing mode.

   Some PDF documents don't have tags. In this case, Adobe Reader analyzes the document and temporarily adds tags to improve the reading order of the PDF document. It does this any time that you use assistive technology, the Save As Text feature in Adobe Reader, or the Read Out Loud feature in Adobe Reader.

   Note: If a particular untagged PDF document is very long or you refer to it often, it's a good idea to tag the document permanently. You can add permanent tags to the PDF document by using Acrobat 7.0 Professional or Standard. Instructions for doing so are in this guide's companion document, Creating Accessible PDF Documents with Adobe Acrobat 7.0: A Guide for Publishing PDF Files for Use by People with Disabilities. You can download the document at http://www.adobe.com/enterprise/accessibility.

2. Alternate text descriptions for figures, form fields, and links

   A second feature of accessible PDF documents is descriptive text, called alternate text, for figures, form fields, and web links. Screen readers and other text-to-speech tools typically can't read these page elements, so authors of accessible PDF documents add alternate text to describe them. When screen readers encounter alternate text, they can interpret the element and read its alternate text description aloud to you.

3. Navigational aids

   Accessible PDF documents also have navigational aids, which include links, bookmarks, a table of contents, and an optimized, preset tab order for forms and embedded links. These navigational aids enable you to go directly to a particular place in a document, instead of reading it through page by page.

4. Security that doesn't interfere with assistive technology

   Some authors of PDF documents restrict users from printing, copying, extracting, commenting, or editing text. These restrictions can sometimes interfere with a screen reader's ability to convert the on-screen text to speech. An accessible PDF document is both secure and available to a screen reader.

   Note: If your particular assistive technology product is registered with Adobe as a Trusted Agent, you can read PDF documents that might be inaccessible to another assistive technology product. Adobe Reader recognizes when a screen reader or other product is a Trusted Agent and overrides security settings that would typically limit access to the content for accessibility purposes. However, the security settings remain in effect for all other purposes, such as to prevent printing, copying, extracting, commenting, or editing text.

5. Fonts that allow characters to be extracted to text

   A fifth characteristic of an accessible PDF document is that the fonts within it contain enough information for Adobe Reader to correctly extract all of the characters to text for purposes other than displaying text on the screen. For example, Adobe Reader extracts characters to text any time you listen to text by using a screen reader or the Read Out Loud tool, or when you print, copy and paste, or save text to a file.

   If the font's underlying information is sufficient, Adobe Reader can extract each character correctly each time you do these tasks. If the font's information is insufficient, Adobe Reader cannot substitute characters correctly, and the output will be faulty. For instance, the screen reader or Read Out Loud tool may seem to ignore words or characters, or you may get question marks, black rectangles, or similar marks when you print, copy, paste, or save a PDF document as text. If the font does not contain enough information for Adobe Reader to correctly extract all characters of text, the PDF document is considered inaccessible.

Some Adobe PDF documents may be inaccessible

You may occasionally encounter some Adobe PDF documents that are not accessible, especially if you use assistive technology. A PDF document can be inaccessible for a variety of reasons. The most common reasons are the following:

• The author created the document before Adobe enhanced the PDF specification to support accessibility.
• The author did not apply the techniques for optimizing the PDF document for accessibility, so the document lacks the tagging or the structured reading order that assistive technology needs to interpret the text correctly.
• The author created the document as a PDF form that was created without fillable fields. You must print a hard copy and complete this form manually.
• The author created the PDF document by scanning a printed page or importing an image format, so the text is merely an image that assistive technology can't read.

Note: If you have Acrobat 7.0 Professional or Standard, you can convert scanned PDF documents to text that can be tagged and structured for screen readers. Instructions for doing so are in this guide's companion document, Creating Accessible PDF Documents with Adobe Acrobat 7.0: A Guide for Publishing PDF Files for Use by People with Disabilities. You can download the document at http://www.adobe.com/accessibility.

How to determine if an Adobe PDF document is accessible

Adobe Reader includes an accessibility Quick Check tool that you can use to determine whether a particular Adobe PDF document is tagged and structured in a way that serves assistive technology. See "Performing an accessibility Quick Check" for instructions on using Quick Check.

Accessibility features in Adobe Reader 7.0

Adobe Reader has many accessibility features to help people with motion or vision limitations to navigate and view Adobe PDF documents more easily in Windows and Mac OS. You can adjust many of these features in Adobe Reader at any time.

Note: The complete set of accessibility features that is described in this document is available only in the Full version of Adobe Reader 7.0. To download the latest Full version of Adobe Reader, go to http://www.adobe.com/products/acrobat/readstep2.html.

Adobe Reader has the following accessibility features:

• The Accessibility Setup Assistant, a wizard for setting up almost all accessibility preferences at once based on your particular assistive technology. See "Running the Accessibility Setup Assistant".
• Support for assistive technology, such as screen readers, screen magnifiers, and the accessibility features of the Windows and Mac OS operating systems.
• Read Out Loud, a built-in text-to-speech tool that you can use if you do not have access to a screen reader. See "Using the Read Out Loud tool".
• Reflow view, so you can read multicolumn layouts as one column of text. Reflow view is useful when you do not have a screen magnifier, or when you are using a PDA. See "Using Reflow view for easy, single-column reading".
• Auto-scrolling through documents, to reduce required keyboard actions. See "Using automatic scrolling".
• The option to save a PDF document to text for Braille or other output. See "Saving an Adobe PDF document as text".
• Numerous preferences to control how screen readers and the Read Out Loud tool read PDF documents. See "Section 4: Customizing Adobe Reader for your accessibility needs".
• The ability to customize color contrast to make text and images easier to view. See "Setting color contrast for improved readability".
• Keyboard alternatives to most mouse actions for navigating PDF documents. See "Navigating the Adobe Reader interface by using the keyboard".

Adobe accessibility website

For more information on accessibility and Adobe PDF documents, visit the Adobe accessibility Web site at http://www.adobe.com/accessibility.

• Printable version (PDF: 3.8M)