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Remediating PDF Documents

cammie.vloedman@ssbbartgroup.com 06/18/12

PDF Remediation

A lot of people panic when they see the number of violations listed for a PDF document. Many believe that remediating PDF documents is difficult. The reality is this – there are a lot of steps involved in remediating PDFs, but it is not difficult. Allow yourself plenty of time and follow these tips and you’ll be golden.

The most time consuming elements when remediating PDFs are usually tables and list structures. The following are some hints for remediating all types of elements in PDF documents:

  • Use the table editor to your advantage when remediating tables. The table editor provides a GUI interface to identify content as a table header, set the scope of the cell, set the span width of the row or column cell, name the header and/or associate any headers to the cell all in one convenient dialog.
    • When naming table headers for use in complex tables, don’t put spaces in the name. Spaces will prevent the header from being properly recognized by assistive technology (AT).
  • Lists typically include a large number of tags in the structure so that they are properly read which can make it challenging to ensure the tags are aligned.
    • Use the plus and minus signs to collapse and expand tags to more easily view the level on which each item is nested. Think of a family tree when determining the level at which each tag needs to reside. All the children of a particular parent would be indented spatially in the list of items under the parent. The children’s names would vertically begin at the same place on each line. If a vertical line can be drawn between the first letters of each child’s name then they are at the correct level.
    • A list should always begin with a parent L (identifies the content as a list) tag. Each list item (LI – holds the tags that contain the contents of a item in the list) needs to be nested beneath that L tag.
    • Be sure each list item has a nested LBL (holds the bullet or number) and LBody (holds the list item text) tag.
    • Ensure all list items are contained under one parent L tag. This is especially important when lists span multiple pages.
  • Images need to contain concise, meaningful alternate text if the image is important to understanding the content. If the image is decorative, find the image tag in the tags structure and change it to an artifact.
    • Complex images still need alternate text but it should be concise. A more in-depth description of the image should appear in-line within the surrounding text, in a surrounding table or list or in an appendix. When using an appendix, be sure to indicate where users can find the more thorough description of the graphic.
    • Don’t put “Picture of..”, “Image of…” or “Description:” at the beginning of alternate text.
  • Use headings to identify all sections and topics within the document. Headings help users navigate the document more easily and understand the hierarchical flow of the document.
    • Be consistent about which heading level is used for each type of content. For example, all chapter names might be structured at heading level 2. All topics within a chapter might be structured at heading level 3.
    • Use the heading levels in order from 1-6. Try to make sure that 1’s, 2’s, 3’s, etc. are used in that order as deep as necessary to nest content. Don’t structure section titles as heading 2’s and then topics within the sections as heading 5’s.
  • Links need meaningful link text descriptions and they need to be keyboard accessible.
    • Avoid using phrases such as “click here”, “link to” or other generic phrases as the actual link text. Each link needs to be unique text.
    • Make sure the same link text is not used more than once throughout the document. Again, each link needs to be unique.
    • Use the Tab key on the keyboard to tab through the document to see if each link is highlighted with a focus rectangle and that the Enter/Return key will activate the link. In the tags structure a Link-OBJR tag must appear as a sibling to the Link text (a child of the Link tag) in order for the link to be keyboard accessible.
  • Use color to make the document appealing, but do it in an accessible way.
    • Watch out for poor color contrast. Poor contrast primarily affects users with low vision and those who are color blind. For example, using white text on a light blue background would likely not meet necessary contrast ratios.
    • Don’t use color to convey meaning. If you need to indicate important information add textual representation in addition to the color. Some examples would be adding a * before required fields on a form or adding “Note:” before an important paragraph of text.
  • Improper reading order is a very common issue we field during testing. Assistive technology uses the tags structure to read the document; therefore, if the tags are not in a meaningful order then the information will seem garbled to AT users. If using Adobe Acrobat to remediate your documents, you can check the reading order without running AT. Use the “Highlight Content” option on the context menu of any tag in the tags structure to show where something appears in the document. The content will be highlighted in the document by a blue rectangle and by using the up and down arrow keys you can see the order in which the content will be read.

Here are some additional tips that can help you successfully remediate PDF documents that you may not have known:

  • Make sure your document is tagged! In Acrobat if you open the tags pane and it says “No Tags Available” then the document is not tagged. You can also check for tags by navigating to the File menu, selecting Properties, and under the Advanced section locate the Tagged PDF line where it will either say “yes” or “no”. You can easily add tags to your document by navigating to Tools > Accessibility > Add Tags to Document. Remember, additional remediation will still be necessary. Not all items can be properly tagged automatically, and images, for example, cannot have alternate text automatically applied.
  • Don’t leave your document as a scanned document. To determine whether your document is a scanned document or not, in Acrobat run the Accessibility Quick Check under the Document menu. If the results dialog reports “The document appears to contain no text. It may be a scanned image,” the document is not tagged and structured for accessibility. Another approach is to try to select the text with the mouse pointer. If the text cannot be highlighted by itself, the document is an image.
  • All the tags in the Tags pane can be expanded or collapsed at once by pressing Shift + 8.
  • The Text Edit tool can help you correct a spelling mistake that might cause the content to not make sense when read. This tool will also allow you to change the text color which could be used to improve color contrast.
  • Flowcharts need an alternative such as a list or table to show the hierarchy of the information.
  • If you go to activate the TouchUp Properties dialog and it appears grayed out, one way to get the dialog to be editable again is to press F2 on the keyboard on the tag that you need to edit. The tag will become editable, delete and then replace a letter, press Enter/Return and try accessing the properties dialog again.
  • If the document contains redacted content, ensure there is a tag where that content would be and that it has alternate text applied to it to indicate the content has been redacted.
  • Avoid using watermarks if at all possible. If not tagged properly, watermarks can be misconstrued as content by assistive technology. Watermarks can also make it difficult for users with low vision and those who are color blind to read the document.
  • Ensure the correct element type is associated with the content. If, for example, an image, list or link is not properly identified, AT users may not know how to interact with the element. Also avoid custom tags when possible as they may not be mapped properly and items will not be correctly identified.
  • Properly structured elements also affect how a document reflows. Reflow is important for users with low vision and those with mobility impairments. When a document is reflowed there is no horizontal scroll bar. Check your document’s reflow by navigating to View > Zoom > Reflow in the menu structure or by using the CTRL + 4 keyboard shortcut.

With a little time and effort your PDF documents can be made accessible. There are many resources available to help you with your specific questions. Sign up for a free trial of SSB’s Accessibility Management Platform (AMP) to get access to best practices with information, code samples and testing instructions for PDF documents. SSB staff has also helped the VHA Section 508 Office produce PDF tutorials which you may also find helpful. Good luck!