Why do my PDF’s need to be accessible?
One of the criteria of the WCAG 2.1 is that PDF’s on your site must be accessible to all users regardless of their ability or context of use. As we’ve had some inquiries on what exactly makes a PDF accessible and how to do this, we thought we would write a quick guide on what can be done.
Many of the actions required, though not all, are intended for people who use a screen reader. For this reason, most of the modifications are not visible, and there may be no visually perceivable differences between the regular PDF and the accessible PDF.
How can we make our PDF’s Accessible?
If you are using Adobe Acrobat Pro, they actually have accessibility in mind. If you go to “more tools” and then scroll down to “protect & standardise” and then “accessibility” you get a whole host of accessibility tools including a checker that tests the document for you and points out any errors and how to fix them.
But for those of you who want to do this manually, here are some of the most important things you can do and how to do them:Add a title to your document.
Choose File > Properties > Description. Enter a title in the Title text box. Click Initial View, and then choose Document Title from the Show drop-down list. Click OK to close the Description dialog box.
Indicate the language of the document and all content on the document that is in a language different from the main one. To do this go to File > Properties > Advanced and then select a language from the drop-down list in the Reading Options section near the bottom of the box.
Ensure that security settings do not interfere with access to information by the screen reader. A document author can specify that no part of an accessible PDF is to be copied, printed, extracted, commented on, or edited. This setting could interfere with a screen reader's ability to read the document, because screen readers must be able to copy or extract the document's text to convert it to speech. Choose File > Properties > Security then Choose No Security from the Security Method drop-down list. Click OK and close the Document Properties dialog box.
Include alternative text on any images used in the document. You will need to follow the steps above to get up the accessibility tab to appear. Within this tab there is an option to “set alternative text”.
Scanned in documents or images of documents must be converted to readable text. When possible, avoid scanning in images of documents or using images. When this is unavoidable, Choose Tools > Enhance Scans. The Enhance Scans toolset is displayed in the secondary toolbar. In the secondary toolbar, choose Recognize Text > In This File. Select the pages you want to process, the document language, and then click Recognize Text. You may have to do some editing of the text if the picture was too indecipherable.
Tag the document correctly, that is, indicate internally what type each content is (a header, a table, or a list). Thus, the screen reader properly announces the content, and the user can "browse" the document by jumping from a type of element to the next one using keyboard shortcuts. You can do this by going to Tools > Accessibility > Reading Order. Select the content, and then apply tags as necessary. Alternatively, in the accessibility panel, click the option of “autotag document” (note, this may not be as accurate as tagging the document manually but may be easier)
Review the internal reading order. Note, this does not always match the visual order so if it is done wrong the screen reader will read the document in disorder and therefore be incomprehensible to the user. Again, in the accessibility tab there is an option at the bottom for “reading order” If you click the button near the bottom labelled “show order panel”, you can see in what order the screen reader will read the document. By clicking and dragging on the icon to the left of each section, you can change the order the information will be read.
Very few of the requirements can be corrected completely automatically, always requiring manual and specialised work. It is also important to follow a work methodology and perform the actions in a certain order, for greater efficiency and to avoid problems that cannot be resolved without generating the PDF again or can only be corrected in a more complex way. Using the accessibility tools in Microsoft word before converting the document to a PDF can also help in the long run.
There are also other requirements that go into further detail which you can read here: https://helpx.adobe.com/acrobat/using/create-verify-pdf-accessibility.html