Operation Manual

Table Of Contents

244

USING ACROBAT X STANDARD

Accessibility, tags, and reflow

Last updated 10/11/2011

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/.

More Help topics

“Recognize text in scanned documents” on page 46

“Set the document language” on page 258

“Prevent security settings from interfering with screen readers” on page 258

“Keys for accessibility” on page 346

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.