The specification describes the required and prohibited components and the conditions governing their inclusion in or exclusion from a PDF file in order for the file to be available to the widest possible audience, including those with disabilities. Of note for accessibility is PDF/UA (Universal Accessibility) which became an ISO Standard in July 2012 (ISO 14289-1:2012 (See PDF/UA (ISO 14289-1:2012).) The scope of PDF/UA is not meant to be a techniques (how-to) specification, but rather a set of guidelines for creating more accessible PDF. In January 2008, PDF 1.7 became an ISO standard (ISO 32000-1). The PDF specification was introduced by Adobe Systems in 1993 as a publicly available standard. PDF files specify the appearance of pages in a document in a reliable, device-independent manner.
The Portable Document Format (PDF) is a file format for representing documents in a manner independent of the application software, hardware, and operating system used to create them, as well as of the output device on which they are to be displayed or printed.
