Pages 232-248 of the Adobe Reader X Help Manual

Chapter 10: Accessibility, tags, and reflow

Accessibility features assist people with disabilities, such as mobility impairments, blindness, and low vision in their use of Adobe Acrobat X Standard and Adobe PDFs.

Contents

Accessibility features

About accessibility features

A document or application is accessible if it can be used by people with disabilities, such as mobility impairments, blindness, and low vision. Accessibility features in Adobe Acrobat, Adobe Reader, and Adobe Portable Document Format (PDF) enable people with disabilities to use PDF documents, with or without screen readers, screen magnifiers, and braille printers.

Making PDFs accessible tends to benefit all users. For example, the document structure that enables a screen reader to read a PDF out loud also enables a mobile device to reflow and display the document on a small screen. Similarly, the preset tab order of an accessible PDF form helps all users, not just users with mobility impairments, fill the form more easily.

Accessibility features in Acrobat and Reader fall into two broad categories: features to make the reading of PDF documents more accessible and features to create accessible PDF documents. To create accessible PDF documents, use Acrobat, not Reader.

Features for accessible reading of PDFs

For more information about accessibility features, see these online resources:

About accessible PDFs

Accessible PDFs have the following characteristics.

Searchable text

A document that consists of scanned images of text is inherently inaccessible because the content of the document is images, not searchable text. Assistive software cannot read or extract the words, users cannot select or edit the text, and you cannot manipulate the PDF for accessibility. Convert the scanned images of text to searchable text using optical character recognition (OCR) before you can use other accessibility features with the document.

Fonts that allow characters to be extracted to text

The fonts in an accessible PDF must contain enough information for Acrobat to extract all of the characters to text for purposes other than displaying text on the screen. Acrobat extracts characters to Unicode text when you read a PDF with a screen reader or the Read Out Loud feature. Acrobat also extracts characters to Unicode when you save as text for a braille printer. This extraction fails if Acrobat cannot determine how to map the font to Unicode characters.

Reading order and document structure tags

To read a document's text and present it in a way that makes sense to the user, a screen reader or other text-to-speech tool requires a structured document. Document structure tags in a PDF define the reading order and identify headings, paragraphs, sections, tables, and other page elements.

Interactive form fields

Some PDFs contain forms that a person is to fill out using a computer. To be accessible, form fields must be interactive to let the user enter values into the form fields.

Navigational aids

Navigational aids in a PDF include links, bookmarks, headings, table of contents, and preset tab order for form fields. Navigational aids assist users in understanding the document without reading completely through it. Bookmarks are especially useful and can be created from document headings.

Document language

Specifying the document language in a PDF enables some screen readers to switch to the appropriate language.

Security that doesn't interfere with assistive software

Some PDF authors restrict users from printing, copying, extracting, adding comments, or editing text. The text of an accessible PDF must be available to a screen reader. You can use Acrobat to ensure that security settings don't interfere with the screen reader's ability to convert onscreen text to speech.

For more information about PDF accessibility, see www.webaim.org/techniques/acrobat/.

About tags, accessibility, reading order, and reflow

PDF tags are similar in many ways to XML tags. PDF tags indicate document structure: which text is a heading, which content makes up a section, which text is a bookmark, and so on. A logical structure tree of tags represents the organizational structure of the document. Therefore, tags indicate the reading order and improve navigation, particularly for long, complex documents without changing the PDF appearance.

Assistive software determines how to present and interpret the content of the document by using the logical structure tree. Most assistive software depends on document structure tags to determine the appropriate reading order of text. Document structure tags let assistive software convey the meaning of images and other content in an alternate format, such as sound. An untagged document does not have structure information, and Acrobat must infer a structure based on the Reading Order preference setting. This situation often results in page items being read in the wrong order or not at all.

Reflowing a document for viewing on the small screen of a mobile device relies on these same document structure tags.

Often, Acrobat tags PDFs when you create them. To determine whether a PDF contains tags, choose File > Properties, and look at the Tagged PDF value in the Advanced pane of the Description tab.

Reading PDFs with reflow and accessibility features

Setting accessibility preferences

Acrobat provides several preferences that help make the reading of PDFs more accessible for visually impaired and motion-impaired users. These preferences control how PDFs appear on the screen and how they are read by a screen reader.

Most preferences related to accessibility are available through the Accessibility Setup Assistant, which provides on- screen instructions for setting these preferences. Some preferences that affect accessibility aren't available through the Accessibility Setup Assistant including preferences in the Reading, Forms, and Multimedia categories. You can set all preferences in the Preferences dialog box.

The names shown for some preferences in the Accessibility Setup Assistant are different from the names for the same preferences shown in the Preferences dialog box. Acrobat Help uses the names shown in the Preferences dialog box.

For more information about accessibility features, see www.adobe.com/accessibility.

Set accessibility preferences with the Accessibility Setup Assistant

  1. Start the Accessibility Setup Assistant by doing one of the following:
  2. Choose the option that is appropriate for your assistive software and devices. The assistant presents only preferences that are appropriate for your assistive software and devices, according to the option that you choose.
  3. Follow the on-screen instructions. If you click Cancel at any point, Acrobat uses default settings for the preferences set by the assistant (not recommended).

Set accessibility preferences with the Preferences dialog box

Accessibility preferences

Accessibility preferences in Accessibility panel

Replace Document Colors
When this preference is selected, you can choose from a list of contrasting color combinations for text and background, or you can create your own. These settings correspond to the Use High Contrast Colors For Document Text option in the Accessibility Setup Assistant.
Always Use Page Layout Style
Corresponds to the Override Page Layout Style option in the Accessibility Setup Assistant.
Use Document Structure For Tab Order When No Explicit Tab Order Is Specified
Improves navigation of form fields and links in documents that don't specify a tab order.
Always Display The Keyboard Selection Cursor
Select this option if you use a screen magnifier. This preference corresponds to the Always Display The Keyboard Selection Cursor option in the Accessibility Setup Assistant.
Always Use The System Selection Color
When selected, the default selection color (blue) is overridden with a color that the system specifies.
Show Portfolios In Files Mode
When selected, shows PDF Portfolio component files and file details in a list. Files mode provides a better reading experience for people with disabilities, such as mobility impairments, blindness, and low vision.
Always Use Zoom Setting
Corresponds to the Override Document Zoom option in the Accessibility Setup Assistant. TODO Does it?

Accessibility preferences in Documents panel

Automatically Save Document Changes To Temporary File Every
When deselected, this preference disables the auto- save action. Each time a PDF is saved, the screen reader or magnifier must reload the document. This preference corresponds to the Disable Document Auto-Save option in the Accessibility Setup Assistant.

Accessibility preferences in Forms panel

Fields Highlight Color and Required Fields Highlight Color
These preferences specify what colors will be used to highlight fillable form fields. They correspond to the Field Highlight Color and Required Field Highlight Color options in the Accessibility Setup Assistant.
Auto-Complete
Enables Acrobat to automatically offer to complete some entries in form fields so that filling form fields requires fewer keystrokes. This preference doesn't correspond to an option in the Accessibility Setup Assistant.

Accessibility preferences in Internet panel

Display PDF In Browser
Causes PDFs linked to from web pages to open in the web browser instead of a separate Acrobat window. Deselect this preference for greater control when navigating a document in a screen reader. This preference corresponds to the Display PDF Documents In The Web Browser option in the Accessibility Setup Assistant.

Accessibility preferences in Multimedia panel

These preferences don't correspond to any options in the Accessibility Setup Assistant.

Accessibility preferences in Page Display panel

Zoom
Sets the on-screen magnification of documents and allows low-vision readers to read reflowed PDFs more easily. This preference corresponds to the Override Document Zoom option in the Accessibility Setup Assistant.
Smooth Text
Controls anti-aliasing of text. To disable smoothing of text and make text sharper and easier to read with a screen magnifier, choose None. This preference corresponds to the Disable Text Smoothing option in the Accessibility Setup Assistant.

Accessibility preferences in Reading panel

Reading Order
Specifies the reading order of documents. The reading order preferences also appear in the Accessibility Setup Assistant.
Infer Reading Order From Document (Recommended)
Interprets the reading order of untagged documents by using an advanced method of structure-inference layout analysis.
Left-To-Right, Top-To-Bottom Reading Order
Delivers the text according to its placement on the page, reading from left to right and then top to bottom. This method is faster than Infer Reading Order From Document. This method analyzes text only; form fields are ignored and tables aren't recognized as such.
Use Reading Order In Raw Print Stream
Delivers text in the order in which it was recorded in the print stream. This method is faster than Infer Reading Order From Document. This method analyzes text only; form fields are ignored and tables aren't recognized as such.
Override The Reading Order In Tagged Documents
Uses the reading order specified in the Reading preferences instead of that specified by the tag structure of the document. Use this preference only when you encounter problems in poorly tagged PDFs. This preference corresponds to the Override The Reading Order In Tagged Documents option in the Accessibility Setup Assistant.
Page Vs Document
This preference determines how much of a document is delivered to a screen reader at a time. If a PDF isn't tagged, Acrobat may analyze the document and attempt to infer its structure and reading order, which can take a long time for a long document. You may want to set Acrobat to deliver only the currently visible page so that it analyzes only a small piece of the document at a time. This consideration will vary depending on the size and complexity of the document and on the features of the screen reader. When Acrobat delivers information to a screen reader, screen magnifier, or other assistive software, it loads information into a memory buffer that is directly available to the assistive software. The amount of information that is delivered to the memory buffer can affect how long Acrobat takes to perform tasks, such as opening the document, advancing to the next page, changing views, and carrying out commands.
Only Read The Currently Visible Pages
This option is usually best when you use a screen magnifier. It improves performance by eliminating the need for the software to process parts of the document that aren't visible. When Acrobat sends only the currently visible pages of a PDF to the memory buffer, the assistive technology has access to those pages only. It cannot go to another page until the next page is visible and Acrobat has sent the page information to the memory buffer. Therefore, if this option is selected, you must use the navigation features of Acrobat, not those of the assistive technology, to navigate from page to page in the document. You should also set the Default Page Layout option in preferences to Single Page if you choose to have Acrobat send only the currently visible pages to the assistive technology. Because Acrobat sends page information about all visible pages, the assistive technology receives information about pages that may be only partially visible (such as the bottom of one page or the top of the next), as well as those pages that are completely visible. If you use a page display setting other than Single Page, such as Continuous, and then you display the next page, the technology may not correctly track which portion of a previous page it has already read aloud. For instructions on setting the default page layout to Single Page, see "Preferences for viewing PDFs" on page 14.
This option corresponds to the Only Read The Currently Visible Pages option in the Accessibility Setup Assistant.
Read The Entire Document
This option can be best if you use a screen reader that has its own navigation and search tools and that is more familiar to you than the tools in Acrobat. This option corresponds to the Read The Entire Document At Once option in the Accessibility Setup Assistant.
For Large Documents, Only Read The Currently Visible Pages
This option is selected by default and is usually best if you use a screen reader with long or complex PDFs. It allows Acrobat to deliver an entire small document but revert to page-by-page delivery for large documents. This preference corresponds to the For Large Documents, Only Read The Currently Visible Pages option in the Accessibility Setup Assistant.
Confirm Before Tagging Documents
When selected, lets the user confirm the options that will be used before Acrobat prepares an untagged document for reading. Tagging can be a time-consuming procedure, especially for larger documents. This preference corresponds to the Confirm Before Tagging Documents option in the Accessibility Setup Assistant.
Read Out Loud Options
Set preferences in this section to control volume, speed, and pitch of the voice used for Read Out Loud. You can choose to use the default voice or any of the voices provided by your operating system. You can also use the up and down arrows to read blocks of text. These preferences do not have corresponding options in the Accessibility Setup Assistant.

Enable single-key accelerators

You can select some tools and perform some actions with single-key accelerators. Most keyboard shortcuts in Acrobat don't require that you enable single-key accelerators.

Note: Some screen readers do not work with Acrobat single-key accelerators.

Scroll automatically

The automatic scrolling feature makes it easier to scan through long PDFs, especially reflowed documents. You can scroll through pages without using keystrokes or mouse actions.

  1. Choose View > Page Display > Automatically Scroll.
  2. Do any of the following:

To stop automatic scrolling, press Esc or choose View > Page Display > Automatically Scroll again.

Reflow a PDF

You can reflow a PDF to temporarily present it as a single column that is the width of the document pane. This reflow view can make the document easier to read on a mobile device or magnified on a standard monitor, without scrolling horizontally to read the text.

You cannot save, edit, or print a document while it is in Reflow view.

In most cases, only readable text appears in the reflow view. Text that doesn't reflow includes forms, comments, digital signature fields, and page artifacts, such as page numbers, headers, and footers. Pages that contain both readable text and form or digital signature fields don't reflow. Vertical text reflows horizontally.

Acrobat temporarily tags an untagged document before reflowing it. As an author, you can optimize your PDFs for reflow by tagging them yourself. Tagging ensures that text blocks reflow and that content follows the appropriate sequences, so readers can follow a story that spans different pages and columns without other stories interrupting the flow.

To quickly check the reading order of a document, view it in Reflow view.


Headings and columns (left) reflow in a logical reading order (right)

Reflow a tagged PDF

If the Page Display setting is Two-Up before you choose Reflow view, the Page Display setting automatically becomes Single Page when the document is reflowed. If the Page Display setting is Two-Up Continuous before you choose Reflow view, the Page Display setting automatically becomes Continuous when the document is reflowed.

Return to unreflowed view