Adobe 09972554AD01A12 Accessibility Guide - Page 5

PDF Accessibility Overview a PDF file in a systematic fashion. Systematically ruling out or confirming certain characteristics found in a PDF file will guide the author to the most appropriate path for making an individual PDF document accessible. Note: These Best Practices techniques require access to Adobe Acrobat Pro XI for Windows. Adobe Reader XI and Adobe Acrobat XI Standard do not have the complete set of tools needed to create and validate PDF documents for accessibility. Start with an Accessible Document The PDF format is a destination file format. PDF files are typically created in some other application. Optimally document accessibility should begin in the native document format. For example, many documents are created in a word processing or desktop publishing application, and then exported as PDF documents. There many things that can be done in native document applications to support accessibility, such as adding alternative text for images; defining structural headings, lists, and data tables; providing document language; and setting document properties such as titles. Adobe desktop publishing applications such as Adobe InDesign and Framemaker support these features, as well as other word processing applications such as Microsoft Word. For information on building accessibility into documents created with Adobe products visit the Adobe Accessibility website. To gain assistance on adding accessibility into Microsoft Word documents prior to conversion to PDF format please visit the Microsoft Enable website. Making the native document accessible allows for less work when changes are made to the native document and the PDF document is regenerated. If the native document is not available, in most cases, the document can still be made fully accessible. Without accessibility in the native format there will likely be more manual work required in the PDF to properly tag the document. There are some items such as choosing sufficient contrast between foreground and background colors that must be implemented in the native document. Characteristics of Accessible PDF files Accessible PDFs include but are not limited to the following characteristics: Searchable text A document that consists of scanned images of text is inherently inaccessible because the content of the document is a graphic representing the letters on the page, not searchable text. Assistive technology software cannot read or extract the words in a graphical representation. Furthermore, users cannot select or edit the text or manipulate the PDF for accessibility. Scanned images of text must be converted into to searchable text using optical character recognition (OCR) before addressing accessibility in the document. Fonts that allow Characters to be Extracted to Text The fonts in an accessible PDF must contain enough information for Acrobat to correctly 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 tool, or when you save as text for a Braille embosser. This extraction fails if Acrobat cannot determine how to map the font to Unicode characters. Adobe® Acrobat® XI Pro Accessibility Guide: Best Practices for PDF Accessibility 2