SAIF: A Brief Guide to PDFs and Accessibility
2. Creating PDFs (continued)
Desktop published files are created using a series of text boxes. These individual boxes can be made accessible using the alternative text description. However, screen-reading software might not read the boxes in the order the author intended. This happens if the text boxes have been moved around during the design of the finished document. Screen-reading software cannot track these changes and tends to recognise only the first layout used.
PDFs created from Spreadsheets can also be difficult especially if table cells are merged or split (see the section on Tables further on).
PDFs created by simply scanning a document and saving it as a PDF will always be inaccessible to screen-reading software unless it is created using virtual scanning techniques.
2.1 Creating Accessible Source Documents
When creating a document you need to think not only about its content and visual impact but also about its structure.
All electronic documents have a structure that is unseen but is vital in making your information more accessible. It is the document's structure that screen-reading software uses to "read" the document.
Information within the document structure is also used by search engines to find relevant documents during an Internet search. Producing well-structured documents helps to ensure that the information you post on the Internet is found by the people you want to read it.