At a high level, the process of creating accessible PDFs consists of a few basic stages:
Workflow for creating accessible PDFs
These stages are presented in an order that suits most needs. However, you can perform tasks in a different order or iterate between some of the stages. In all cases, first examine the document, determine its intended purpose, and use that analysis to determine the workflow that you apply.
Guide to creating accessible PDFs, General Services Administration: www.section508.gov/docs/PDFGuidanceForGovernment.pdf
Best practices: amp.ssbbartgroup.com
Whenever possible, think about accessibility when you create the source files in an authoring application, such as a word-processing or page-layout application.
Typical tasks in the authoring application include adding alternate text to graphics, optimizing tables, and applying paragraph styles or other document-structure features that can be converted to tags. For more information, see Creating a tagged PDF from an authoring application.
If you have Acrobat Pro and intend to design PDF forms, use Adobe LiveCycle® Designer, which is dedicated to the design of interactive and static forms. LiveCycle Designer adds structure tags to forms, improving accessibility.
If your PDF includes form fields, use Tools > Accessibility > Run Form Field Recognition to detect form fields and make them interactive (fillable).
Use the Forms tools to create fillable form fields, such as buttons, check boxes, pop-up menus, and text boxes. When you create a field, type a description in the Tooltip box in the Properties dialog box for that field. Screen readers read this text aloud to the user. For more information, see Create form fields.
You can also use the Touch Up Reading Order tool in Acrobat Pro to add descriptions to form fields.
In Acrobat Pro DC, this stage includes setting the document language, making sure that security settings don’t interfere with screen readers, creating accessible links, and adding bookmarks. For more information, see Set the document language, Prevent security settings from interfering with screen readers, Add accessible links, and About bookmarks.
In Acrobat Standard DC, this stage includes setting the document language, making sure that security settings don’t interfere with screen readers, and adding bookmarks. For more information, see Set the document language, Prevent security settings from interfering with screen readers, and About bookmarks.
Improve the accessibility of PDFs by adding tags in Acrobat. If a PDF doesn’t contain tags, Acrobat attempts to tag it automatically when users read or reflow it, and the results may be disappointing. With a tagged PDF, the logical structure tree sends the contents to a screen reader or other assistive software or hardware in an appropriate order.
For best results, tag a document when converting it to PDF from an authoring application. Examples of these applications include Adobe FrameMaker®, Adobe InDesign®,Microsoft Word, or OpenOffice Writer. If you do not have access to an authoring application that can generate a tagged PDF, you can tag a PDF any time by using Acrobat.
Tagging during conversion to PDF requires an authoring application that supports tagging in PDF. Tagging during conversion enables the authoring application to draw from the paragraph styles or other structural information of the source document to produce a logical structure tree. The logical structure tree reflects an accurate reading order and appropriate levels of tags. This tagging can more readily interpret the structure of complex layouts, such as embedded sidebars, closely spaced columns, irregular text alignment, and tables. Tagging during conversion can also properly tag the links, cross-references, bookmarks, and alternate text (when available) that are in the file.
To tag a PDF in Acrobat, choose Tools > Accessibility > Add Tags To Document. This command works on any untagged PDF, such as one created with Adobe PDF Printer. Acrobat analyzes the content of the PDF to interpret the individual page elements, their hierarchical structure, and the intended reading order of each page. Then, it builds a tag tree that reflects that information. It also creates tags for any links, cross-references, and bookmarks that you added to the document in Acrobat.
The Add Tags To Document command adequately tags most standard layouts. However, it cannot always correctly interpret the structure and reading order of complex page elements. These elements include closely spaced columns, irregular text alignment, nonfillable form fields, and tables that don’t have borders. Tagging these pages by using the Add Tags To Document command can result in improperly combined elements or out-of-sequence tags. These issues cause reading order problems in the PDF.
For more information, see Add tags to an existing PDF (Acrobat Pro DC).
You can add a watermark to a tagged PDF without adding it to the tag tree. Not having a watermark appear in the tag tree is helpful for people who are using screen readers, because they won’t hear the watermark read as a document content.
The best way to add a watermark that doesn’t interfere with screen readers is to insert an untagged PDF of the watermark into a tagged PDF.
Once you have a tagged PDF, evaluate the document for reading order problems, tagging errors, and accessibility errors, and then repair them as needed.
Whichever method you use to tag the PDF, use Acrobat to touch up the tagging and reading order for complex page layouts or unusual page elements. For example, the Add Tags To Document command can’t always distinguish between instructive figures and decorative page elements such as borders, lines, or background elements. It may incorrectly tag all of these elements as figures. Similarly, this command may erroneously tag graphical characters within text, such as drop caps, as figures instead of including them in the tag that represents the text block. Such errors can clutter the tag tree and complicate the reading order that assistive technology relies on.
If you tag a document from within Acrobat, the application generates an error report after it completes the tagging process. Use this report as a guide to repair tagging problems. You can identify other tagging, reading order, and accessibility problems for any PDF by using the Full Check tool or the Touch Up Reading Order tool. For more information, see Check accessibility with Full Check and Check and correct reading order.
Create a tagged PDF from a web page
A PDF that you create from a web page is only as accessible as the HTML source that it is based on. For example, if the web page relies on tables for its layout design, the HTML code for the table may not flow in the same logical reading order as a tagged PDF would require, even though the HTML code is sufficiently structured to display all the elements correctly in a browser.
Depending on the complexity of the web page, you can do extensive repairs in Acrobat Pro by using the Touch Up Reading Order tool or editing the tag tree in Acrobat.
To produce the most accessible PDFs from web pages you create, first establish a logical reading order in their HTML code. For best results, employ the Web Content Accessibility Guidelines that are published by theWorld Wide Web Consortium (W3C). For more information, see the guidelines on the W3C website.
Creating a tagged PDF from an authoring application
In most cases, you create tagged PDFs from within an authoring application, such as Adobe FrameMaker®, Adobe InDesign, or Microsoft Word. Creating tags in the authoring application generally provides better results than adding tags in Acrobat.
PDFMaker provides conversion settings that let you create tagged PDFs in Microsoft Excel, PowerPoint, and Word.
For more information about creating accessible PDFs, see www.adobe.com/accessibility.
For more information, see the documentation for your authoring application.
About tags in combined PDFs
You can combine multiple files from different applications in one operation to create a single PDF. For example, you can combine word-processing files with slide presentations, spreadsheets, and web pages. Choose File > Create > Combine Files Into A Single PDF.
During conversion, Acrobat opens each authoring application, creates a tagged PDF, and assembles these PDFs into a single tagged PDF.
The conversion process doesn’t always correctly interpret the document structure for the combined PDF, because the files being assembled often use different formats. Use Acrobat Pro DC to create an accessible PDF from multiple documents.
When you combine multiple PDFs into one tagged PDF, it is a good idea to retag the combined document. Combining tagged and untagged PDFs results in a partially tagged PDF that isn’t accessible to people with disabilities. Some users, such as those using screen readers, are unaware of the pages that don’t have tags. If you start with a mix of tagged and untagged PDFs, tag the untagged files before proceeding. If the PDFs are all untagged, add tags to the combined PDF after you finish inserting, replacing, and deleting pages.
When you insert, replace, or delete pages, Acrobat DC accepts existing tags into the tag tree of the consolidated PDF in the following manner:
When you insert pages into a PDF, Acrobat adds the tags (if any) for the new pages to the end of the tag tree. This order occurs even if you insert the new pages at the beginning or the middle of the document.
When you replace pages in a PDF, Acrobat adds the tags (if any) from the incoming pages to the end of the tag tree. This order occurs even if you replace pages at the beginning or the middle of the document. Acrobat retains the tags (if any) for the replaced pages.
When you delete pages from a PDF, Acrobat retains the tags (if any) of the deleted pages.
Pages whose tags are out of order in the logical structure tree can cause problems for screen readers. Screen readers read tags in sequence down the tree, and possibly do not reach the tags for an inserted page until the end of the tree. To fix this problem, use Acrobat Pro DC to rearrange the tag tree. Place large groups of tags in the same reading order as the pages themselves. To avoid this step, plan on inserting pages to the end of a PDF, building the document from front to back in sequence. For example, if you create a title page PDF separately from the content, add the content PDF to the title page PDF, even though the content document is larger. This approach places the tags for the content after the tags for the title page. It’s unnecessary to rearrange the tags later in Acrobat Pro.
The tags that remain from a deleted or replaced page don’t connect to any content in the document. Essentially, they are large pieces of empty tag tree sections. These redundant tags increase the file size of the document, slow down screen readers, and can cause screen readers to give confusing results. For best results, make tagging the last step in the conversion process. Use Acrobat Pro DC to delete the tags of deleted pages from the tag tree.
For more information, see Create merged PDFs.
About tools for creating accessible PDF forms
Acrobat Pro DC, Acrobat Standard DC
Use one of these applications to open untagged or tagged PDF forms (except PDF forms that are created from LiveCycle Designer) to add fillable form fields, such as text boxes, check boxes, and buttons. Then use the application’s other tools to make the form accessible. Add descriptions to form fields, tag untagged forms, set the set tab order, manipulate tags, and perform the other PDF accessibility tasks.
(Available in Acrobat Pro DC) Use this product to design and build new forms or to import untagged PDF forms and make their form fields fillable and accessible. You can deploy forms in tagged PDF, XML, and other formats from LiveCycle Designer. Once you create or edit an Acrobat form in LiveCycle Designer, it becomes a LiveCycle Designer file. It is no longer a PDF that you can edit or manipulate in Acrobat. Both Acrobat and Reader can open and read PDF forms that you create fromLiveCycle Designer. These PDF forms, however, don’t include permissions to modify the file. Therefore, use LiveCycle Designer only for PDFs that are intended to contain only form-based information. Don’t use it to add form fields to a document that combines pages of narrative with an occasional page that has form fields. In this case, use Acrobat Pro to add the form fields. Then complete the accessibility tasks for the rest of the document content.
Most authoring applications that you can use to design forms don’t retain their fillable form fields when you convert the files to PDF. Use the forms tools in Acrobat Pro DC to add fillable form fields. Moreover, if you tag the form during conversion to PDF, the authoring application can generate inappropriate tags for the text labels of the form fields. In a complex form, for example, the text labels for all the fields can run together into a single line. Screen readers can’t interpret these fields as individual labels. Such reading order problems can require time-consuming work in Acrobat Pro DC to split the labels apart. In this case, producing an untagged PDF form from the authoring application is sometimes the better course. You can then use the Forms tools in Acrobat Pro DC to add fillable form fields before you tag the entire document. Some forms are straightforward enough that you can produce a tagged PDF from the authoring application. Then perform light touch-up in Acrobat Pro DC after you add the fillable form fields.
Workflow for creating accessible PDF forms
Using Acrobat, you can open untagged and tagged PDF forms, add fillable form fields, add field descriptions and alternate text, set the tab order, and tag the forms (if they aren’t already tagged). You can also edit the tags of any tagged PDF form by using the Touch Up Reading Order tool or the tag tree.
Forms tend to have relatively complex layouts compared to documents that have a simple, single-column structure. The success that an application has in analyzing and tagging a form depends largely on the original formatting and layout of a document, and the types of fields that it uses.
When you design a form, include headings, instructions, and fields in which users are to enter data. At a minimum, give each field a label. Also add special instructions for fields that need them. Use graphics tools to draw lines and boxes. Don’t use characters, such as underscores and vertical bars, because these text characters can confuse screen readers.
Adding descriptions to form fields enables screen readers to identify the fields to users. Users hear the description read aloud when they tab to the field. Write descriptions that are terse but complete. For example, the description “First name” is appropriate for a first-name field. Don’t use instructions (such as “Enter first name”) as a description.
The tab order for form fields enables people with disabilities to use a keyboard to move from field to field in a logical order. In PDF forms, set the tab order to Use Document Structure. You can test the tab order of a form by using the following keyboard commands:
Tab to move focus to the next field
Shift+Tab to move focus to the previous field
Spacebar to select options
Arrow keys to select options or list items
If the PDF form is already tagged, use the Touch Up Reading Order tool in Acrobat to tag each form field. This tool also enables you to fix any reading order problems of the text labels for the form fields. For example, you may need to split merged lines of fields into individual fields.