Alternate text descriptions for figures, form fields, and links
Authors of accessible PDF documents add descriptive alternate text to page elements that
are typically presented not as text but only as visual elements, such as graphics, figures,
form fields, and links. When screen readers encounter alternate text, they can interpret the
element and read its alternate text description aloud.
Navigational aids
Similar to accessible Web pages, accessible PDF documents also include navigational
aids, such as links, bookmarks, a table of contents, and an optimized tab order for forms
and embedded links. These navigational aids enable a user to go directly to a particular
point in a document, instead of reading it through page by page.
Security that doesn’t interfere with assistive technology
When creating PDF documents, some authors add restrictions to prevent users from
printing, copying, extracting, commenting, or editing text. These restrictions can interfere
with a screen reader’s ability to convert the on-screen text to speech. The content of an
accessible PDF document is available to screen readers, regardless of the security
restrictions in place.
Fonts that allow characters to be extracted to text
The fonts used in an accessible PDF document 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; 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 perform one of these tasks. If the information is
insufficient, Adobe Reader cannot substitute characters correctly, and the output will be
incomplete. For instance, the screen reader may omit words or characters, or you may see
question marks, black rectangles, or similar marks when you print, copy and paste, or
save a PDF document as text. If a PDF document contains one or more fonts that do not
contain enough information for Adobe Reader to correctly extract all characters to text, the
document is considered inaccessible.
Exemptions from Accessibility Requirements:
Maps
Aerial photographs
Musical scores (score only – lyrics must be transcribed)
03/2009
