Adobe Acrobat Reader adds an accessible tagged structure to PDFs that resembles HTML markup. Screen readers are able to read these tags. Simple PDFs that don’t contain images, graphs or tables are more effectively tagged and are easier to read for screen readers.
There is a process to add and edit tags through Acrobat, InDesign, Word, Excel and PowerPoint, but this process is time consuming and cumbersome. The tagging interfaces are difficult to use and confusing. If a PDF is not tagged through any of the programs listed above, Acrobat Reader will add tags on the fly when the untagged PDF is opened.
The recommended procedure is to save untagged PDFs as version 1.6 (Acrobat 7.0) or later. By default, tagging is not activated in InDesign, Word, Excel and PowerPoint. Any PDFs produced from the those programs will be untagged.
If there is a concern that a locally downloaded PDF will go out of date or contains content that needs to be updated frequently, do not use a PDF document for the data. When a user downloads a PDF version of a document to a hard drive, that PDF is static and cannot be updated like an HTML page. A new version of the PDF may be posted on a Web site, but the user might not download it or use it. It is best to post a frequently updated document or information as HTML so it can be easily controlled and updated and there is less worry of having local PDFs that can’t be updated.
When a person clicks on a link of a Web site, he expects to see another HTML page, not a PDF. PDFs often take too much time to load, hang up browsers and cause confusion.
Newsletters formatted to be printed usually have multiple columns and images and require more complex formatting. It is best to convert these to PDFs.
Often style guides need to be produced to show designers and writers how to format Web sites, electronic documents and print collateral. PDFs work great for style guides because they retain complex formatting and different fonts that are not available on most computers.
Not all PDFs are meant for public download, some are only meant to printed and distributed. Documents like Patient Family Education materials are created to be printed out and handed to patients and families along with a discussion and education from a health care professional.
Forms may need to be downloaded, filled out and brought into a doctor's office or hospital. PDFs work great for this.