What is an accessible PDF?

An accessible PDF is a digital document in PDF format whose full content is accessible to people with disabilities through the use of suitable hardware and softwareOr from another perspective: if a person with disabilities (e.g. blindness) cannot perceive the content of documents despite using suitable software (e.g. reading software) (e.g. because the document cannot be read aloud), then a barrier exists.

But what does that mean exactly?

information absorption in humans

If all 5 sense organs are functioning, we can receive information through smell, taste, touch, hearing and sight. For the transmission of a large amount of information, the sense of smell and taste are of course irrelevant. So we almost exclusively use the See or Hear or both. The sense of touch we still need to access the information – for example, by leafing through a book.

Information capture in PDF files

PDF files mimic a digital version of a physical written document. They are therefore primarily designed to display information visually. PDF software is therefore also specialized in the visual presentation of information. Over the years, more and more additional functions have been added, so that PDF documents can now also contain audio and video, but this is extremely rare.

creation of barriers

And with this background information, it is also relatively easy to clarify how barriers can arise in the transfer of information between the PDF and a person. Namely, precisely when the relevant sensory organ is restricted. In the case of a PDF document, the barrier arises mainly when the sense of sight is restricted. Of course, a barrier can also arise if the document contains audio tracks in rare cases and the sense of hearing is restricted. Or if the document can only be operated using complex input methods and the sense of touch is restricted. The last two barriers mentioned almost never occur, however.

 

Requirements for an accessible PDF

The goal of an accessible PDF is to remove the barriers so that the entire content can also with Restrictions are perceptible. And this gives rise to the requirement that the content not as usual only visually is made available, but also auditory – and also a easy operation is possible.

 

Technical implementation

Just as there is software suitable for the visual representation of a PDF, there is now also software suitable for the auditory transmission of information. These are so-called screen readers, i.e. reading software. We therefore have to not additionally record it as an audio track, but simply ensure that the document is machine-readable. This results in the following example requirements:

• Each component of the document must be tagged, i.e. provided with a label so that the software knows whether it is a normal paragraph, a heading, a list, a link or something else. This is the basic requirement for making the PDF machine-readable. It also gives the user the option of jumping back and forth within a particular group of components (e.g. headings). This allows them to quickly and easily get an overview of the document.
• A reading order must be present so that it is clear which content should be read first.
• The document language must be set so that the software pronounces the words correctly.
• For illustrations that are relevant to the content (images, diagrams, icons, shapes, etc.), alternative text must be available that contains all the relevant information in the illustration.

Of course, there are many other technical requirements to be observed, which arise from the standards and laws on accessibility issues. Find out more about these (standardized and legally defined) technical requirements for accessible PDF documents.