There are several types of structural elements that aid in navigation and organization of PDF documents. Providing structure helps all users understand the content in the document. Moreover, structure allows users of AT to navigate using AT-specific commands to jump to or skip content.
The most important step to begin creating an accessible document is to ensure that the document contains a tag structure. Tag structure can be checked by running the Accessibility Quick Check under Tools > Accessibility > Quick Check in Acrobat X or by opening the tags panel and confirming there is “No Tags available” message. Access the Tags pane through the menus by navigating to and activating the View > Show/Hide > Navigation Panes > Tags options.
If it is confirmed the document does not contain a tag structure, tags can be added to the document in Acrobat X by navigating to and activating “Tools” > “Accessibility” > “Add tags to Document”.
Managing Headers and Footers
Headers and footers contain important pieces of information that need to be readable by all users. However, when users of screen reading technology hear this content, it can be confusing to discern which information is part of the main page content versus the header/footer information.
The example above shows how, depending on the context of the content, it could be confusing to understand the point being conveyed by the information. The image shows a document that has a sentence that breaks across pages. The page content shown improperly reads “...Computer paper was bought in quantities of 10 300 pound crates…” The correct information and intention of the sentence is misconstrued when read in that order. The sentence should read “...Computer paper was bought in quantities of 300 pound crates…” Therefore, header/footer content needs to be placed appropriately in the reading order or made an artifact.
Non-unique header/footer content, for example, the repeated company name on each page, needs to be tagged only on the first page. It is recommended to leave the content visually on the page, but to tag the repeated content as an artifact. For more information about tagging artifacts, see the Hiding or “Artifacting” Non-Meaningful Content tutorial. For unique content such as notes, footnotes, remarks, etc., the content needs to be placed appropriately in the reading order.
Dealing with Watermarks
If not tagged properly, watermarks can be misconstrued as content in a document when read by ATs. When watermarks are inserted in source documents, the watermark content sometimes gets tagged as content on each page of the document. It is best to avoid watermarks, but if they are needed they should be added from within Acrobat so that the watermark is properly tagged.
When adding watermarks in Acrobat, document authors need to be mindful of the color contrast of the watermark. By selecting an appropriate shade of color and adjusting the opacity, watermarks will not conflict with page content. For more information on this topic, refer to the Using Color tutorial.
To add or update a watermark in Acrobat X:
- Navigate to and activate Tools.
- Navigate to and expand Pages.
- Under Edit Page Design, activate the Watermark link.
- Locate and activate Add Watermark… or Update…
- Confirm the Add Watermark/Update Watermark dialog appears.
For text watermarks, the font color and shade of the text can be changed through the color picker button.
For both text and graphic watermarks the opacity can be changed with the opacity slider or by editing the percentage next to the slider control.