Top 5 accessibility fixes for your existing PDF documents
Adobe Acrobat Professional comes with a variety of features to make your PDF documents accessible for differently abled readers. Creating accessible documents helps achieve standards compliance and improved search results.
When creating the PDF documents from the source files, you can cover the broad canvas of accessibility easily, using the various documented methods. In this article I shall touch upon the procedures to make your existing PDF documents accessible. In a typical workplace scenario, you may have inherited PDF documents that may or may not be accessible. You may not have the bandwidth to re-generate your legacy documents from the source files. At times even the source files may not be readily available.
Whatever your scenario is, you will find Adobe Acrobat Professional workflows handy for enhancing the accessibility of your existing documents.
Run OCR on a scanned document
If a PDF is a scanned document, the content is really an image, which cannot be searched but only viewed. Run Optical Character Recognition (OCR) on the document to identify the text in it and embed the text for reading by assistive software.
Open an image PDF document and click Tools > Text Recognition > In This File. To do a bulk operation across multiple documents, click Tools > Text Recognition > In Multiple Files.
See the detailed steps at Scan documents to PDF. For quick OCR tips, also see Adobe Acrobat quick tips and best practices for OCR.
Add Document Properties and metadata
Information such as document title, document subject, document author, and document keywords, is considered part of the XMP metadata of a PDF document. Information provided in the XMP metadata fields improve accessibility by helping a human as well as a non-human entity to determine the nature of the document, categorize the document, and search for the document.
Click File > Properties, and set the values in the Description tab. To do batch operations on multiple PDF documents, you can fill these fields programmatically using Acrobat SDK.
For detailed documentation, see PDF properties and metadata help article. For quick tips, see Quick fixes to do before you publish your PDF documents.
Set alternative text
Alternative text for any element of a PDF document helps visually impaired readers understand the element. For an information-rich graphics, for example a large screenshot or a graph, write a concise alt text that describes or captures just the highlight of the graphic. You can add alt text to not just the graphics but also to the links and the form fields in a PDF document.
To set alt text for graphics in a PDF file, click Tools > Accessibility > Set Alternate Text. Adobe Acrobat Professional scans the images used in the document and a popup dialog allows you to add or edit alt text.
While a screen reader can read a URL, it makes more sense to a user to know what the URL is about through the provided alternate text for the URL. To set alt text for links and form fields in a PDF file, open the tag structure for a PDF, locate the link or the form element, open properties of the element, and edit the Alternate Text field.
Tag a PDF document or define flow
Tagging helps assistive software define the sequence of document elements. Without appropriate tags, a document may not flow well and a visually impaired reader may end up accessing the contents in a wrong order.
For existing PDF documents, you can use the tagging feature of Adobe Acrobat to create what is called a tag tree or check and update and existing tag tree. While adding tags in an existing PDF document is not the optimum solution, it certainly boosts accessibility. For an optimum solution, create tagged PDF documents from source files. For more information, see Creating Accessible PDFs.
Convert the URLs in a document to live links using Link Tool, run OCR on scanned documents, and make the form fields fillable. Now add tags by opening the Tags pane from View > Show/Hide > Navigation Panes > Tags, and clicking Add Tags to Document.
After creating tags, Adobe Acrobat may generate a Recognition Report, which includes further pointers to improve the tagging manually, for example hints about adding alt text and touching up the reading order. Examine these results and follow the provided hints for repair.
More information on tagging is available in the article Editing document structure with the Content and Tags panel.
Act on the detailed accessibility report
Beyond executing the above top-level accessibility workflows, you can (and should!) run the accessibility checker for a full-blown report on a document’s accessibility. While fixing the above issues will make your document more accessible, other apparently smaller issues can mar the experience of a reader. For example, if the fonts used in a PDF file are not accessible or if the metadata is encrypted, none of the above fixes can help a reader access the content.
Fixing accessibility issues across a large repository of PDF files—a probable scenario in an enterprise setup—may be a daunting task that requires you to prioritize your resources. A comprehensive report obtained before resorting to any of the above solutions will give you an idea about the level of adherence to the common accessibility standards. Also, you can use the data to prioritize the primary fixes for your document set.
To run a complete check on your document, click Tools > Accessibility > Full Check. In the Accessibility Checker Options dialog box, select All Pages In Document and click Select All to run all the checks on the entire document.
Accessibility in Adobe Acrobat line of products: www.adobe.com/accessibility/products/acrobat.html
Accessibility in Adobe Acrobat: helpx.adobe.com/acrobat/topics/accessibility-tags-and-reflow.html
PDF accessibility page for more information: www.adobe.com/products/acrobat/pdf-accessibility-wcag-508-compliance-standards.html