At the time of testing (March 2013), Acrobat 10 Pro provides a set of accessibility features that is sufficient to enable the production of accessible digital documents. In addition, Acrobat 10 Pro includes an accessibility checking feature.
Note: It may be problematic to use PDF for documents that must be accessible. In the past, the non-semantic nature of PDF and creating PDF documents from raw scanned images gave PDF a reputation for poor accessibility. In the last few years, the accessibility of the PDF format has been improved (especially with the release of PDF-UA). However, support for accessible PDF by authoring tools, viewers and assistive technologies (e.g., screen readers) still lags similar support for HTML documents (though see Accessible PDF Support Tools). For example, many of the accessible authoring features in Acrobat 10 (e.g., "Touch Up Reading Order") do not support the "undo" function and it is more difficult for users to set their own display styles (e.g., text color, background color, fonts, etc.). That said, there are some advantages to PDF, notably single page files facilitate off-line sharing, more consistent page numbering, support for off-line form-filling. Therefore, we recommend considering HTML instead of or in addition to PDF where appropriate.
What’s an “Office Document”?
You should use the techniques bellow when you are using Acrobat 10 Pro to create documents that are:
- Intended to be used by people (i.e., not computer code),
- Text-based (i.e., not simply images, although they may contain images),
- Fully printable (i.e., where dynamic features are limited to automatic page numbering, table of contents, etc. and do not include audio, video, or embedded interactivity),
- Self-contained (i.e., without hyperlinks to other documents, unlike web content), and
- Typical of office-style workflows (Reports, letters, memos, budgets, presentations, etc.).
Note: If you are creating forms, web pages, applications, or other dynamic and/or interactive content, these techniques will still be useful to you, but you should also consult the W3C-WAI Web Content Accessibility Guidelines (WCAG 2.0) because these are specifically designed to provide guidance for highly dynamic and/or interactive content. In addition, the W3C WCAG-WG has provided PDF Techniques for WCAG 2.0.
The default file format for Acrobat 10 Pro is Adobe Portable Document Format (PDF). In addition, Acrobat 10 Pro offers several other word processor and web format saving options. These have not been checked for accessibility.
We have tried to formulate these techniques so that they are useful to all authors, regardless of whether they use a mouse. However, for clarity there are several instances where mouse-only language is used. Below are the mouse-only terms and their keyboard alternatives:
- *Right-click: To right-click with the keyboard, select the object using the Shift+Arrow keys and then press either (1) the “Right-Click” key (some keyboard have this to the right of the spacebar) or (2) Shift+F10.
- *Drag: Unfortunately, there is no keyboard alternative for several operations that require dragging.
Disclaimer and Testing Details:
- Following these techniques will increase the accessibility of your documents, but it does not guarantee accessibility to any specific disability groups. In cases where more certainty is required, it is recommended that you test the office documents with end users with disabilities, including screen reader users.
- The application-specific steps and screenshots in this document were created using Adobe Acrobat 10 Pro (ver.10.0, Windows 7, Mar. 2011) while creating a PDF document..
- Tasks completed in Technique 3, Technique 4, and Technique 5 cannot be undone. It is recommended that you save your PDF document before and after you make significant changes. This document is provided for information purposes only and is neither a recommendation nor a guarantee of results.
- If errors are found, please report them to: firstname.lastname@example.org
Technique 1. Use Accessible Source Documents
In the Adobe Acrobat 10 Pro workflow, all PDF documents start with a source document created in an office document authoring application, such as Microsoft Word or OpenOffice.org Writer. Because source documents provide the starting-point for the PDF documents, accessibility is very important.
To create an accessible source document
- Create a new document in the authoring application (from the default blank template or from one of the prepackaged templates)
- Ensure that you follow the ADOD Authoring Techniques provided for the authoring application (available at: http://inclusivedesign.ca/accessible-office-documents)
- When you are finished, you should also check the accessibility of the document (see “Accessibility Checking” in the Authoring Techniques for the authoring application)
Once you have completed the above steps, you are ready to convert your document to PDF using Adobe Acrobat 10.
To convert single source documents to PDF
- Go to the menu item: File > Create PDF > From file...
- Locate and select your source document and select the Open button, Acrobat will then proceed to convert the file.
Note: A batch conversion process is also available from the menu item: File > Create PDF > Batch Create Multiple Files
If you created a PDF from a scanned document, then it will be inherently inaccessible to screen readers and other assistive technologies. In addition, the document will be less useful because graphic representations of text cannot be selected, edited or searched.
In this case, it is necessary that you convert the scanned images of text to searchable content using Acrobat's optical character recognition (OCR) featurebefore addressing the accessibility features of the document.
Technique 2. Check Accessibility
The most basic requirement for a PDF document to be accessible is for it to be "tagged" with hidden labels ("tags") that describes the structure of the document (e.g. that text should be interpreted as a header, paragraph, table cell, etc.). Screen readers can then use these tags to convey the document's information effectively to people with visual disabilities.
The other requirements for a PDF document to be accessible (e.g. alternate text, logical reading order, etc.) can only all apply once the document is tagged.
Note: A"Quick Check" is not recommended.
To perform "Full Check"
Note: If "Accessibility" is not visible under tools, go to menu item: View > Tools > Accessibility
- Select Tools > Accessibility > Full Check Up
Running a Wizard Action Full Check when the file is first created would be ideal. This allows you to fix a few mistakes before the check up.
- Select Tools > Action Wizard > Create Accessible PDF's
Note: If the PDF file was created from InDesign, then select "InDesign CS6 Accessibility Touch up"
- Select "5 Accessibility Check (Full)" (in the Action: Create Accessible PDFs)
- Select Next
- Select the folder to save the file (in Browse For Folder)
- Insert Title and Author (you can also insert subject and keyword). In order to insert you must uncheck the "Leave As Is" button.
- Follow the Wizard (a yellow sticky note-like pop-up box)
- In the Remove Hidden Information pop up box select OK. All of the checked items will be removed.
- Start Checking
- Save file. If the file is not fully accessible the errors (report) will be shown on the left panel).
Technique 3. Add and Edit Tags
Caution!: Actions taken using the TouchUp Reading Order tool and Order Panel cannot be undone. Remember to save your work frequently. If you frequently create PDF files you might consider using one of these accessible PDF support tools.
If tags are missing, then they must be added. When tags are present, they should still be checked for correctness. Acrobat's Help text describes the tags as follows:
- Tags the selection as text.
- Tags the selection as a figure. Text contained within a figure tag is defined as part of the image and is not read by screen readers.
- Form Field
- Tags the selection as a form field.
- Tags a selected figure and caption as a single tag. Any text contained in the tag is defined as a caption. Useful for tagging photos and captions and preventing caption text from being incorrectly added to adjacent text blocks. Figures may still require alternate text.
- Heading 1, Heading 2, Heading 3
- Tags the selection as a first, second, or third level heading tag. You can convert heading tags to bookmarks to help users navigate the document. Additional heading levels (4, 5, 6) are available from the Tags panel.
- Tags the selection as a table. When this selection is made, Acrobat analyzes the selection to determine the location of headings, columns, and rows.
- Tags the selection as a table or header cell. Use this option to merge cells that are incorrectly split.
- Tags the selection as a formula. Because speech software may handle formula tags differently from normal text, you may want to add a description using alternate text.
- Tags the selection as a background element, or artifact, removing the item from the tag tree so that it does not appear in the reflowed document and is not read by screen readers.
To add tags automatically
Note: The automatic tagging feature may be sufficient on simple layouts, but it sometimes misinterprets the structure and reading order of complex page elements (e.g. closely spaced columns, irregular text alignment, and tables without borders.). Therefore, you should still manually check the tags as explained below.
- Go to menu item: Advanced > Accessibility > Add Tags To Document
Note: This command removes any tags that were in the document before the command was run. If any potential problems were encountered, an Add Tags Report appears in the navigation pane.
To Add/Edit Tags Manually
- TouchUp Reading Order…
In most cases, it will help to have the three checkboxes checked (Show page content order, Show table cells, Show tables and figures)
- Using the TouchUp Reading Order tool, drag* within the document pane to select a region of the page that contains one type of content (e.g. a text block)
- To add more page content to the current selection, Shift + drag*
- To remove page content from the current selection, Ctrl + drag*
- Select the appropriate button in the TouchUp Reading Order dialog to specify the tag type, a box should now encapsulate the element (the tags are explained here)
Tips for Tagging:
- A good place to start is tagging "Background" content, since this will reduce the number of tags to deal with. Background content should include:
- empty boxes,
- visible or invisible textbox borders (especially in busy areas where they overlap with text),
- visuals that are decorative or redundant (e.g., backgrounds, illustrations), whose content is described adequately in the text .
- If you are having difficulty tagging complex content (e.g., a complex table), consider either:
- Editing the source document to simplify it, or
- Selecting the complex content and tagging it as a figure for which you must then add alternative text that properly conveys all of the information in the new figure
To change the tag for a region
- With the TouchUp Reading Order tool...
- In the document pane, drag* to select a highlight region or select the number of the highlighted region (or select from the Order Panel)
Note: If you drag* over part of an already tagged element, the element is sometimes split up. This is helpful when splitting larger elements to ensure correct reading over of sub-elements.
- Select the appropriate button in the TouchUp Reading Order dialog to specify the tag (the tags are explained here)
To Modify Tagging
- Tools > Content > Edit Object
- Select items required to be tagged*right click > properties...
- Under Tag select type (paragraph, heading level, span etc.)
Tip: Tagging items and adding alternative text before converting to PDF will save time.
Correcting Visual Side-Effects of Tagging
Sometimes tagging can result in unexpected visual side effects, such as text disappearing behind background images. The following steps can be taken to correct such side-effects:
- Open Content panel (View > Show/Hide > Navigation Panes > Content)
- Move any <Artifact> elements to the top (this places them behind all other elements).
- See if this fixes the problem. If not, continue:
- Click Gears icon > Highlight Content
- Drag* mouse over unwanted element or the area where missing element should be
- Click Gears icon > "Find content from selection" to locate selection in Content tree
- In the Content panel tree, click on the "Container" node of the selected element and then adjacent nodes.
- As you click, note which element is highlighted on screen. When you have found the element you want to correct, continue:
- If you found text that is hidden behind another element, move the hidden element DOWN within the Content panel tree (this moves it above other elements).
- If you found an element that should not be there, move it UP within the Content panel tree (this moves in behind other elements) or delete it if necessary (remember to Save beforehand)
Note: The order of items in the Content panel tree indicates their layer order in the document. If item A is lower in the tree than item B, then if item A and B overlap in the document, A will be in front. Some people find this confusing, so a good way to remember how this works is to imagine putting documents in a pile and noting their names in a list. The last document placed will be on top of the pile, covering the others, and its name will be on the bottom of the list.
Technique 4. Provide Alternative Text
When using images, it is important to ensure that the information you intend to convey by the image is also conveyed to people who cannot see the image. This can be accomplished by adding concise alternative text to each image. If the image is purely decorative, mark it as background.
Tips for writing alternative text
- Try to answer the question "what information is the image conveying?"
- If the image does not convey any useful information, leave the alternative text blank (e.g. Background images should generally have no alternative text, other decorative images should only have alt text if they form a crucial part of the content, message, and purpose of the document)
- If the image contains meaningful text, ensure all of the text is replicated
- For logos, the alternative text should be the organization's name
- For groups of logos, one logo can be chosen to represent the group
- Sometimes text is included as part of a logo or footer image (e.g. the image might contain a phone number), this text should be set as the alternative text of the image
- Alternative text should be fairly short, usually a sentence or less and rarely more than two sentences
- If more description is required (e.g., for a chart or graph), provide a short description in the alternative text (e.g., a summary of the trend) and more detail in the long description, see below
- Test by having others review the document with the images replaced by the alternative text
Tips for writing longer descriptions
- Long descriptions should be used when text alternatives (see above) are insufficient to answer the question "what information is the image conveying?"
- In some situations, the information being conveyed will be how an image looks (e.g., an artwork, architectural detail, etc.). In these cases, try to describe the image without making too many of your own assumptions.
- One approach is to imagine you are describing the image to a person over the phone
- Ensure that you still provide concise alternative text to help readers decide if they are interested in the longer description
- Alternatively, you can include the same information conveyed by the image within the body of the document, providing the images as an alternate to the text. In that case, the images should be marked as "Background" and you do not have to provide alternate text within the image.
To add alternative text to images
- Tools > Content > Edit Object
- Select image *right click > properties...
- Under Tag select type (figure, table etc.)
- Alternative text inserts text
To add alternative text to links
- In the tag tree, select the Link tag for the link
- Select Options > Properties
- In the TouchUp Properties dialog, select the Tag tab
- Type alternative text for the link
- Select Close
To Create Artifact
Artifacts are for objects that are not required to be read out loud (eg. background colours)
- Tools > Content > Edit Object
- Select image *right click > Create Artifact
Technique 5. Set a Logical Reading Order
Setting up reading order will set up the way the device will read the file out loud to view and change reading order:
- Select the Order Pane (View > Show/Hide > Navigation Panes > Order)
- Once the order pane is selected the file will show numbers per page showing the reading order.
- If the reading order is incorrect select the following information from the pane and move the information bellow or above to make the reading order correct.
To test reading order
Sometimes it may not be clear by looking at content, what would be the most logical aural reading order. In these cases, it is recommended to preview the reading order.
Go to menu: View > Read Out Loud > Activate Read Out Loud
To hear a PDF via "Read Out Loud"
The Read Out Loud feature reads the text in a PDF aloud in the available voices installed on your system. In tagged PDFs, content is read in the order in which it appears in the document’s logical structure tree. In untagged PDFs, the reading order is inferred. The Read Out Loud feature can indicate problems or errors in the reading order and document structure. See Technique 3 to learn how to correct document tagging.
Technique 6. Set Document Properties
It is important to set up the PDF correctly in order for assistive technologies (e.g., screen readers) to be able to present your document accurately.
- File > Properties
keyboard shortcut: Ctrl + D (on windows), Cmd + D (on Mac)
- Under Descriptions tab fill in the title and author. (Subject and Keywords can also be filled in)
- Under Initial Views change the following
- Layout and Magnification
- Navigation Tab: Bookmarks Panel and pages
- Magnification: Fit Page
- Open to Page: 1
- Check Center window on Screen
- Show > Document Title
- Under the Advanced tab select Language and change to the preferred language If a different natural language is used for a paragraph or selected text, this also needs to be clearly indicated.
- Select OK
To apply a language directly to selected element
- Go to menu item: View > Navigation Panels > Tags
- In the Tags tab, select the element
- Right-click* the element and select Properties…
- In the Content tab, select the language from the Language drop-down list
- Select Close
To set the page structure to document structure
- Select all the pages (ctrl + A or cmd + A) in the page Thumbnails Panel
- Select Page Properties
- Under Tab Order select Use Document Structure
- Select OK
Technique 7. Adjust Security Settings
It is possible to specify that no part of an accessible PDF is to be copied, printed, extracted, commented on, or edited. This can be accomplished by encrypting the document with password security. However, this 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 in order to convert it to speech. In Acrobat 10 Pro, it is possible to maintain high-encryption-level security while at the same time providing the necessary access to assistive technologies.
To allow assistive technologies access to content
- Go to menu item: File >Properties > Security Properties
- Security Method > Password Security
- In the Password Security - Settings dialog, under Permissions, select Restrict editing and printing of the document
- For low-encryption-level security, select Enable copying of text, images, and other content
- For high-encryption-level security, select Enable text access for screen reader devices for the visually impaired (this overrides the document’s security settings only for the purpose of giving assistive software, such as screen readers, access to the content)
- Select OK
Technique 8. Set Bookmarks
A bookmark is a type of link with representative text in the Bookmarks panel in the navigation pane. Each bookmark goes to a different view or page in the document. In Acrobat 10 Pro, you can use bookmarks to mark a place in the PDF to which you want to return, or to jump to a destination in the PDF, another document, or a web page. There are several ways to create bookmarks.
Note: An Acrobat user can only add bookmarks to a document only if the security settings allow it.
To add a bookmark manually
- Bookmark > New Bookmark
- Insert the title of the content
- Scroll to the page that the bookmark is intended to link.
- *Right click the bookmark title > Set Destination
To add bookmarks automatically
Bookmarks can also be generated automatically from various types of strucutre that will be in your document if you have tagged it properly:
- Bookmark > New Bookmark from Structure (in the drop down menu in the bookmark pane)
- Select the structure to generate bookmarks from.
Accessibility Support Tools
- axesPDF: A plug-in for Microsoft Word 2007/2010 that makes it easier to create accessible PDFs (free public beta program);
- CommonLook Office: A plug-in for Microsoft Word 2007/2010 and PowerPoint 22007/010 that makes it easier to create accessible PDFs.
- CommonLook PDF: A plug-in for Adobe Acrobat that helps identify, report and correct accessibility problems.
- MadeToTag: A plug-in for for Adobe InDesign that makes it easier to create accessible PDF from InDesign documents.
- PDFGoHTML: A free Adobe Acrobat plug-in that converts tagged PDF into HTML, which can be useful in debugging tagging structures.
References and Resources
Authors: Vellicia Christanto, Jan Richards
This document was produced as part of the Accessible Digital Office Document (ADOD) Project. This project has been developed by the Inclusive Design Research Centre, OCAD University as part of an EnAbling Change Partnership project with the Government of Ontario and UNESCO (United Nations Educational, Scientific and Cultural Organization).
Substantial contributions have also been made to the project by AnySurfer, the City of Toronto, and OCAD University.
Accessible Digital Office Documents (ADOD) Project by Inclusive Design Research Centre (IDRC) is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Updated: 23 Apr 2013