Before discussing the accessibility of PDF files, it is important to distinguish between Adobe, Acrobat and PDF. These terms are often used interchangeably, but they are not the same.
The terms Adobe, Acrobat, and PDF are related in the same way as Microsoft, Word, and doc.
There are 3 Acrobat Tools:
When people talk about "accessible" PDF files, they are usually referring to "tagged" PDF files. PDF tags provide a hidden, structured representation of the PDF content that is presented to screen readers. They exist for accessibility purposes only and have no visible effect on the PDF file. There is more to an accessible PDF file than tags, but an untagged PDF would not be considered "accessible".
HTML tags and PDF tags often use similar tag names (e.g., both have tags named h1) and organization structures. If you are comfortable with HTML, you will probably have an easier time creating and editing tagged PDF files, but knowledge of HTML is not necessary.
A great deal of effort is often devoted to remediating PDF files with accessibility issues. This is sometimes necessary, but most of this work can be avoided by choosing a source document that supports PDF accessibility, making the document as accessible as it can be, and then converting it correctly to a PDF.
PDFs are typically created in one of two ways:
Several programs support creating accessible documents keep their accessibility information intact when converted to PDF. These include Microsoft Office, Adobe InDesign, LibreOffice, and OpenOffice.org.
The most popular of these tools—Microsoft Office—has good overall accessibility that continues to improve with each version. For example, a document created in Word should contain almost all the information necessary for an accessible PDF, including:
After the PDF conversion, some cleanup in Acrobat may still be necessary. Decorative images will need to be hidden (unless you are using Office 365 for Windows), table headers will need to be assigned a scope, and tables with multiple levels of headers will require more significant work (which should encourage creating simpler tables when possible). But these are the exception—other accessibility information should carry over cleanly.
If you receive a PDF that is untagged, or where the tag structure is incomplete or incorrect, it is usually best to return to the source document, make the necessary accessibility repairs, and then re-create the PDF. If the source document is unavailable, you can use Acrobat to convert a PDF back to a Word, Excel, or PowerPoint file. Select File > Export To, then choose your desired format.
This doesn't always create a workable document, but because most fixes are easier to make in the source document format, this has the potential to save a great deal of effort.
To create a PDF in Acrobat Standard or Pro, select File > Create > PDF from File.
If you are on Mac, there is an additional step in this process. After selecting the file to convert, check the Use Adobe Create PDF cloud service checkbox.
Acrobat should remember this selection for future PDFs, but it is probably best to confirm this checkbox is checked every time you create a PDF. Because this PDF is created in using Adobe's cloud service, there may be times when the PDF does not look identical to the original file, but this is unavoidable.
When you install a compatible version Acrobat on your computer, Adobe will also install an add-in called PDFMaker that allows you to create a PDF without leaving Word, PowerPoint, or Excel. On Windows, this PDF will be identical to the PDF created through Acrobat.
To create a PDF using this feature, select the Acrobat tab, then Create PDF.
A tagged PDF is created by default. If this is not the case, select Preferences from the Acrobat tab, and make sure Enable Accessibility and Reflow with tagged Adobe PDF is checked.
On Mac, the Acrobat tab only works correctly in Word. To convert a PowerPoint or Excel file to a tagged PDF, you must open Acrobat and create the PDF there. It also requires some setup when using it for the first time in Word.
Before creating your first PDF, click the Preferences button on the Acrobat tab. Then, check the Prompt for using Adobe Create PDF cloud service checkbox and click OK.
To create a PDF:
Saving as a PDF in Office also allows you to create tagged PDF files without installing Acrobat. The tagging process will not be as clean as with the Adobe add-in, so we recommend using Acrobat if you have it. As with the Acrobat tab, this process is different for Windows and Mac.
This should create a tagged PDF by default. If it does not, choose More options before you save the file. A new window will appear. Select Options, make sure Document structure tags for accessibility is checked, then save the file.
On Mac, the "Save As" option will only create tagged PDFs in certain programs. Only Word is supported in Office 2016, Word and Excel are supported in Office 365, and PowerPoint is currently not supported in any version of Office for Mac.
Never choose a "Print to PDF" option in Office, or in any other program. A screen reader user may still be able to access the text of a PDF created in this way, but heading structure, alternative text, and any other tag structure will be lost.
Adobe Acrobat Professional is the most commonly-used program to evaluate, repair, and enhance the accessibility of existing PDF files. This article outlines accessibility features and best practices in Acrobat DC and XI.
The two most important tools for reviewing and repairing PDF accessibility are the Tags pane and the Accessibility tools pane. They are both hidden by default in Acrobat, so you will need to go through a one-time process to make these tools visible and available.
To open the Tags pane for the first time, select View > Show/Hide > Navigation Panes > Tags.
The Tags pane will appear in a sidebar on the left side of Acrobat. To show or hide this pane in the future, click the "Tag" icon in on the far-left side of the window.
Go back to the PDF you are working on and you will now see Accessibility in the right-hand sidebar. Click it to open a group of accessibility tools.
You will likely move between the Tags pane and accessibility tools multiple times while repairing a PDF.
PDF "tags" determine the order and structure of PDFs for screen reader users, and the Tags pane allows you to view, reorder, modify, create, and delete these tags.
This pane displays all the tags within the PDF, organized in a tree structure. This tags tree can be navigated, expanded, and collapsed using a mouse or the arrow keys on the keyboard. Many of the tags are similar, if not identical to tags in HTML. The most notable difference is
<Figure> tag, which is like the
<img> tag in HTML.
Selecting a tag should highlight the corresponding text, image, or other element in the PDF file.
If the tags pane shows "No Tags available" and you do not have access to the source document used to create this PDF, you will need to add tags to this document. To add tags to an untagged document that contains text, choose the Options menu in the Tags pane, then Add Tags to Document. You will need to review the generated tags and usually do some repairs, but that is almost always easier than creating the entire tag structure manually. This is especially true if the document contains tables or lists (assuming Acrobat creates the correct tag structure). If file is a scanned PDF that does not contain text, you must first extract the text in the PDF, as outlined later.
Just as selecting a tag highlights the content in the body of the PDF file, there is a way to accomplish the opposite effect of highlighting the tag that corresponds to selected content. First, click on the Selection Tool (). Next, select the object. Finally, go the Options menu at the top of the Tags pane and then select Find Tag from Selection.
This will highlight the tag or tags that contain the selected content.
At times, you will encounter a PDF file that has missing or incorrect tags. It is often easier to repair these tags using the Reading Order tool outlined below, but there are some actions that can only be accomplished in the Tags pane.
If choosing "Find Tag from Selection" does not highlight a tag in the tree, the content does not have a tag associated with it. To create a tag for the selected content, click the Options menu and select Create Tag from Selection.
To change a tag from one type to another, right-click the tag you want to change, and select Properties. Click on the Type dropdown and select the desired tag.
To delete a tag from the tree, click on the tag, or navigate to it with the arrow keys, and press Delete. Make sure the tag that you are deleting does not contain any content that you want presented to a screen reader.
The Reading Order tool—called Touch Up Reading Order (or TURO) in older versions of Acrobat—helps you add and edit many common PDF tags. To use this tool, go to the Accessibility tools and select Reading Order (or Touch Up Reading Order in Acrobat XI). A dialog will appear. The appearance of the PDF also changes—the content will become encased in numbered gray boxes. If you don't see any boxes, your PDF document is most likely untagged.
By default, each of these gray boxes are numbered to represent the content order of the PDF, but it is best to worry about the structure of the PDF first, then its reading order. To see the tag structure instead, choose the Structure types radio button in the dialog. This will change the view so that the white boxes in the upper left corner of each element displays the tag type (e.g., "P" or "H1") instead of the numbers.
To add or change a tag, use the crosshairs () to draw a box around content you want inside this tag. It is sometimes difficult to select exactly the right area, but it is a little easier if you try drawing a box that is slightly larger than the content. If there is already a gray box around the element, and you just want to change the tag (e.g., changing a heading level), try clicking on the tag in the in the top-left corner of the box. This should select the box, but the behavior can be a bit buggy. You will probably need to switch between these two techniques while repairing a PDF.
After selecting the area, choose the desired tag from the Reading Order window.
|Button||PDF Tag||Additional information|
(Text in XI)
||If you select the image and adjacent text, then the image will be tagged as a figure and the text will be tagged as its caption.|
||Acrobat attempts to assign rows, columns, and headings. Sometimes it does this correctly, but this should still be checked with the table inspector.|
||Can be used to merge cells if they are incorrectly split.|
(Background in XI)
|Artifact||This will hide an item completely from a screen reader. It can be used on images and text.|
If you do not see an option for your desired tag, you will need to create it manually in the Tags pane.
It is often best to remove existing tags a specific item or area before assigning new ones, especially for buttons that create multiple tags like "Table." To remove the structure from an area on the page, select it as outlined above, right-click, and select Delete Selected Item Structure. To clear an entire page, select the Clear Page Structure button in the tool dialog. You can then select items and assign the proper tags.
When an image is tagged as a figure, the alternative text will appear in a black box in the upper left hand corner of the image. If it has no alternative text, the caption will read "Figure - No alternate text exists."
To add or edit alternative text, right click on the image and select Edit Alternate Text. Enter the appropriate alt text in the dialog box.
You may be able to use the Reading Order tool to hide or show text within complex images like charts. For example, if the text in a bar graph is being read by a screen reader when it should be ignored, draw box around the entire chart and select the Figure button. Conversely, if the percentages in a pie chart are being ignored when you want them to be read, try drawing a box around each bit of text and tagging it with the Text/Paragraph button.
The Table Inspector allows you to easily identify, create, and repair table headers.
With the Reading Order tool open, select a table and then select Table Inspector. Click and drag to select a group of the column or row headers. Right click on the selected cell or cells and choose Table Cell Properties.
A dialog box will appear. Select the Header Cell radio button, then select the Scope menu and choose Row or Column (never choose "Both" or "None").
After selecting OK, you will notice that the table header cells are highlighted in red and the data cells will be highlighted in gray. Repeat for all the headers in the table.
Tables with more than one level of row or column headers, or with cells that span multiple rows or columns, may need extensive work to ensure they are presented correctly to screen readers. Whenever possible, simplify your tables to avoid this overhead. If the table structure is very poor, it may be easier to have Acrobat re-tag the table automatically. Click outside the table to exit the Table Inspector, then select the right-click, and choose Delete Selected Item Structure. Draw a box around the entire table and select the Table button. The quality of the tags for a table can vary greatly—Acrobat does best when the table has clear borders between each cell and no background colors.
If you made changes to the tag structure of the PDF, you need to make sure the tag order is correct. It is natural to assume that the Reading Order tool is the place to fix this, but it is actually much more complicated than that.
In addition to the visual reading order, there are two hidden types of "reading order" within a PDF: the tag order that is accessed by screen readers and other assistive technologies, and the lesser-known content order that is used by Adobe when a user selects Reflow (useful on mobile devices). The Reading Order tool displays the content order of the PDF, NOT the tag order.
In other words, even if the order of the numbers in the Reading Order tool looks correct, the PDF may still be read incorrectly by a screen reader. The reverse is probably even more common—in most PDFs created from Word documents, images are placed in the correct place in the tag order, but they typically come at the end of each page in the content order. While the goal is to get the content and tag order to match the visual order, the tag order takes priority in accessibility repairs because that is what will be accessed by a screen reader.
To review and repair the content order, open the Reading Order tool and select the Page content order radio button. The tags in the upper-left corner of each content box will change back to numbers. If the order of these numbers is not correct, select the Show Order Panel button and Acrobat will open the Order pane on the left side of the window.
To change the content order, either click-and-drag the items listed or use the cut and paste keyboard shortcuts—Ctrl (or Command on Mac) + X or V.
Using this page can be confusing. While it displays the content order (not the tags order), changes made within this panel will be reflected in both the tags and content order, but this behavior can be unpredictable. It can cause discrepancies between content and tags order, and even break order that was previously correct, so changes made in the Order pane should be completed first and then verified in the Tags pane.
To check the order of the tags in the PDF, open the Tags pane. Like the Order pane, either click-and drag or with the mouse or cut and paste with the keyboard to change the order. When moving tags around, make sure the nesting of the tags within the tree stays correct.
The built-in accessibility checker "Full Check" is a good tool to use with a new PDF to identify what issues need to be addressed, and after repairing a PDF to ensure no obvious issues were overlooked. To run the checker, select Full Check from the Accessibility tools pane. The results will appear in the "Accessibility Checker" Pane on the left side of the window.
For additional information about an issue, right-click it and select Explain, and Acrobat will direct you to online documentation that outlines the issue, and often tells you how to fix it.
The Accessibility Checker cannot identify all accessibility issues. You should also manually check the document for other potential issues.
To add alternative text to multiple images, go to the Accessibility tools and select Set Alternate Text. The first image in the file will be highlighted, and a dialog box will appear with a space to enter the alternative text. Enter the appropriate alternative text and press the right arrow icon to move to the next image.
There is also a checkbox to identify an image as a Decorative figure. Unfortunately, this feature does not work as it should. If you check this box and run the Accessibility Full Check again, the error for the image will change from "Figures alternate text - Failed" to "Other elements alternate text - Failed." Until this bug is resolved, do not use this checkbox to hide decorative images. Instead, skip over these images by pressing the right arrow button to skip to the next image. After adding alternative text to all the images that need it, select Save & Close. Then use the Background/Artifact button in the Reading Order tool to hide any images that should not be read by a screen reader.
Before you can create a tagged PDF, you must first ensure that the PDF contains real text. If it does not, you must either recreate the PDF file (if you have the source document) or convert it to include true text. To add this tool, go to the Tools tab and find add Enhance Scans. Return to the PDF, select Enhance Scans in the Tools pane, then in the toolbar above the PDF, select Recognize Text > In this File.
The quality of the text depends on the clarity of the source document. To clean up any text that Acrobat had trouble detecting, select Recognize Text > Correct Recognized Text (called Find All Suspects in Acrobat XI).
The Reflow view allows users to reorder the content of a PDF into a simplified, single-column layout, based on the content order.
Select View > Zoom > Reflow or Control + 4. If the document does not appear in the correct order while in Reflow view, fix this using the Order pane, as outlined above.
Acrobat Action Wizards automate common multi-step processes in Acrobat, including several common steps in creating an accessible PDF.
The "Make Accessible" action Wizard can be a useful tool, especially when starting with scanned or untagged PDFs. It is a helpful way to ensure that you don't miss any steps while making your document accessible, like providing a page title or document language. To run the wizard, use the Tools tab to add Action Wizard (it should be visible by default in Acrobat XI), then Open Action Wizard and choose Make Accessible. The wizard will then run you through several steps:
If your PDF is already tagged (e.g., you created a PDF using instructions on the previous page) you must skip step 3: "Recognize Text using OCR." Otherwise, your PDF will be re-tagged, and the new tag structure is seldom as good as the original. To skip this step, preferably before you start the wizard, right-click the Recognize Text using OCR option and select Skip This Step.
You will still want to check your PDF after using this wizard. For a video walkthrough and handout on the "Make Accessible" Wizard, see the GOALS Acrobat cheatsheet.
Compared to HTML, PDF forms have some inherent accessibility limitations. There is no real way to associate the visible text label with the form field, but there is a way to provide a text description that will be read to a screen reader while navigating through the PDF. In addition to the accessibility principles outlined in the previous page of this article, the following four steps are required to ensure the accessibility of a PDF form:
While many of the principles in this article can be applied to older versions of Acrobat Pro, this article is written specifically for users of Acrobat XI Professional.
Most PDF forms start out as Microsoft Word files or other electronic documents with empty spaces for form fields. Actual form fields must be added within Acrobat Professional before the file can be filled out electronically.
With most files, the easiest way to add form fields is to have Acrobat detect and label these fields automatically. There are two main ways to do this:
Form fields can sometimes be incorrectly added to the PDF by Acrobat. This is especially common for cells within a data table or lines that are used to separate page sections. To remove a form control, click on it and press Delete.
To add a form control manually, open the Prepare Form tools, and click on the desired form field type in the toolbar above your PDF. Then drag the field to the correct place on the page. Ensure the new form field covers the existing space (e.g., a new radio button should cover the circle that already appears on the page). Acrobat will prompt you to add a field name. A descriptive name will probably be helpful when reviewing the form data later, but the name will not be read by a screen reader.
When a screen reader user navigates to a form field, its contents must be described to a screen reader user. This descriptive text is typically called a "label" because the
<label> tag is the main way to accomplish this in a webpage. In a PDF, this information is provided through the Tooltip (with the exception of radio buttons, which is explained later).
When Acrobat adds form fields automatically, it also automatically adds a Name and Tooltip to each field based on text near the field. However, you should still review each Tooltip. If you added the fields manually, the Tooltip will be blank.
With the Prepare Form tool group open, right-click a form field and choose Properties. Make sure the text in the Tooltip conveys all the information a screen reader needs to correctly complete the field, and correct it if it does not.
If you are checking multiple Tooltip values, leave the Properties window open in an empty part of the screen and click on each form field.
Fields that are marked "Required" within Acrobat are not identified by a screen reader. Identify required fields in the Tooltip.
The following section provides additional details for specific types of form fields.
In most forms, the most common field type is a text field. There are options within Acrobat Pro to make this single or multi-line.
These menus can be navigated with the arrow keys or by selecting the first letter of the desired option. If an option is selected by default, it will be read by a screen reader in addition to the Tooltip.
A list box looks like an expanded dropdown list and allows the user to select multiple options by holding down the Shift or Control key while selecting an option with a mouse. List boxes introduce accessibility issues for keyboard users and usability issues for everyone. Use a group of checkboxes instead.
Radio buttons (a group of options where only one option can be selected) require additional information to ensure accessibility. The following information must be provided in the Properties dialog:
nameattribute for HTML radio buttons. It also allows a keyboard user to select an option within the group using the arrow keys.
<legend>elements in HTML. Because this information will be read for each option in the group, it should be succinct.
If this information is presented correctly, both the Tooltip and Radio Button Choice values will be read to a screen reader.
Unfortunately, checkboxes cannot be grouped together in the same way as radio buttons. This means that the description of the group of checkboxes (if present) and the description of the checkbox itself should be defined in the Tooltip.
These principles for radio buttons and checkboxes must be balanced with the need for a succinct Tooltip. For example, descriptive text that is merely informative (e.g., "Check all that apply") should probably not be added to each Tooltip. A Tooltip that is extremely long could possibly be added to the first checkbox or radio button with a more succinct Tooltip added to other options. Use your best judgment.
To add text to a button, open the Properties dialog for the button, select the Options tab, and then enter the appropriate text in the Label option. If a button does not have a Tooltip, the text that appears on the button will be read by a screen reader, but if a Tooltip is provided it will override the button text. While adding a Tooltip to a button does not appear to be necessary, the accessibility checker will flag a button without a Tooltip as an error, so it may be best to provide a Tooltip for the button that is identical to the button text.
There is a significant bug in Acrobat—adding form fields to the page does not create the appropriate form tags. If this is not addressed, form fields will not be identified by a screen reader while reading through the file. Unfortunately, fixing this problem does take some time and effort. Once you are done adding the necessary fields and tooltips, follow these steps to add correctly-ordered tags to a form:
<P>tag. This would also be a good time to fix any other tagging issues with your PDF.
Once the form fields are labeled correctly, and the structure order has been corrected, the keyboard navigation order of the form fields should be correct. But it is still a good idea to double-check this, especially if you are relatively new to forms in PDFs. The easiest and most accurate way to test the keyboard navigation order is to save and re-open, and then use the Tab key to navigate the form. Another option is to review the tab order within Acrobat.