CommonLook PDF Accessibility Guide

Description

This article provides instructions on how to prepare, tag, verify, and remediate accessible PDFs using Adobe Acrobat and CommonLook PDF at Idaho State University (ISU).

Guide Navigation

Prepare the PDF in Acrobat

Complete the following tasks before opening the PDF in CommonLook:
  • Resize text boxes.
  • Add or update hyperlinks.
  • Create or update the Table of Contents.
  • Correct color contrast.
  • Embed all fonts.
  • Confirm the PDF contains tags.

Note: CommonLook cannot modify the PDF’s visual appearance or page layout.

Configure CommonLook Settings

Before beginning remediation, configure CommonLook PDF settings to support accurate accessibility reviews.

Recommended Settings

  1. Open Settings
  2. Under Selection enable:
    • Exact
    • Tagged
  3. Clear:
    • Untagged
  4. Select a highlight color.

User Preferences

Enable the following options:
  • Consider elements containing only spaces to be empty.
  • Copy contents of selected tags to Find Text.

Workspace Tips

  • Resize panels by dragging their borders.
  • If the layout becomes unusable, select Reset Panel Locations.

Document Structure

Flatten Tags

Flattening removes unnecessary grouping tags and moves meaningful tags closer to the document root.
  • To flatten tags:
    1. Open the Tags root.
    2. Right-click the Tags tag.
    3. Select Flatten Tags.
Note: This removes unnecessary grouping tags and promotes important tags.

Removing Role Maps

Role maps convert custom tags into their standard PDF equivalents. 
  • To remove role maps:
    1. Open the Tags root.
    2. Right-click the Tags root.
    3. Select Remove Role Maps.
Note: This converts custom tags into standard PDF tags.

Create the Document Tag

The document tag establishes the required document-level structure. 
  • To create the document tag:
    1. Open the Tags root.
    2. Right-click the tags root. 
    3. Select Create Document Tags. 

Note: After completing major tag changes, verify that the document tag remains present. 

Verification

Run verification after making changes.

Structural Verification

  • Check for:
    • Empty tags
    • Missing alternative text
    • Broken links
    • Table structure
    • Lists
    • Table of Contents tags

Accessibility Verification

Select the accessibility standard you want to test.

Note: Structural and Accessibility verification can run simultaneously.

Verification Workflow

After running verification:
  1. Right-click failed items and select Fix Wizard to apply automatic corrections when available. 
  2. Right-click user verification items to manually review and confirm compliance.
  3. After making changes, run an Incremental Check. 
  4. Select Report in the Verification panel to generate a compliance report.
To manually change an error status:
  1. Right-click the error.
  2. Select Change Status.
  3. Update the status as needed.

Working with Tags

Create New Tags

  1. Select the content. 
  2. Open Insert Tag.
  3. Choose the appropriate tag type:
    • Heading
    • Paragraph
    • Other required structure tags
  4. Adjust nesting if necessary.
  5. Remove empty tags.

Convert Tags

Convert existing tags when the current tag type is incorrect.
  • To convert a tag:
    1. Select the tag or content.
    2. Open Convert Tag.
    3. Select the appropriate tag type.
  • Common conversions include:
    • Paragraph
    • Span
    • Caption

Merge Tags

Use Merge Tags when multiple tags should become one.
  • To merge tags:
    1. Select multiple tags.
    2. Right-click.
    3. Select Merge Tags.

Change Tag Order

  • To change tag order:
    • Use:
      • Ctrl + Shift + Arrow Keys

Tagging Untagged Content

When reviewing untagged content:
  1. Open Settings.
  2. Enable Untagged under Selection.
  3. Select the untagged content.
  4. Choose the appropriate tag from Insert Tag.
  5. Disable the Untagged option when finished.

Reviewing Tag Structure

  • When reviewing the tag tree:
    • Use the keyboard arrow keys to expand and collapse tags.
    • Right-click tags to expand all child tags.
    • Verify the reading order matches the document structure.

Pagination

  • Artifact content includes:
    • Page numbers
    • Running headers
    • Running footers

Note: Do not tag artifacts as meaningful content.

  • For tagged pagination:
    1. Select Insert Tag.
    2. Choose Pagination.

Images and Figures

Alternative Text

For each meaningful image:
  1. Select the Figure tag.
  2. Open Properties.
  3. Enter concise alternative text.
  4. Press Tab to save. 

Best Practices

  • Describe only meaningful information.
  • Untag decorative graphics instead of marking them decorative.
  • Describe redacted areas as "Redacted text".
  • Use Actual Text when replacing a character.
  • Use Expansion Text for abbreviations.

Formulas

Use the Formula tag.

Write formulas using words instead of symbols whenever possible.
  • Example: 
    • The square root of x. 

Tagging Captions

To correctly tag figure captions:
  1. Select the paragraph containing the caption text.
  2. Convert the paragraph tag to a Span.
  3. Use Insert Tag and Caption.
  4. Place the caption inside the Figure tag. 

Figure Tags and Additional Guidance

  • If a graphic does not provide meaningful information, remove the tag instead of marking it decorative. 
  • Tag watermarks only once unless they are decorative.
  • If a figure replaces a character:
    • Use the Actual Text field.
  • If a figure contains an acronym:
    • Use the Expansion Text field to provide the full wording. 

Tables

Presentation Tables

Use Linearize Table when a table is used only for layout.
  • Choose:
    • Horizontal
    • Vertical

Note: Test both if necessary.

Data Tables

Ensure every table contains:
  • Table
  • TR
  • TH
  • TD

Note: Set row and column header scope correctly.

Table Captions

  • Place captions:
    • Inside the Table tag
    • Before the first row

Complex Tables

Generate linked headers when multiple rows or columns share one heading.

Multi-Page Tables

When tables continue across pages.
  • Repeat visual headers.
  • Untag duplicated headers before merging.
  • Merge the tables.
  • Verify linked headers.

Generating Tables From Selection

Sometimes tables appear as a series of paragraph tags.
  • To create a table:
    1. Select the entire table.
    2. Select Insert Tag and Generate Table.
    3. Level the table tag up to the root level. 
    4. Run Cleanup:
      • Right-click the tag.
      • Select Cleanup and Skip Empty Cells. 
    5. Open the Table Editor.
    6. Correct:
      • Cell order
      • Spanning
      • Header settings
      • Scope

Basic Data Table Structure

A properly tagged data table should contain:
  • Table
    • TR (Table Row)
      • TH (Header Cell)
      • TD (Data Cell)
Header Rules:
  • Column headers use TH with column scope.
  • Row headers use TH with row scope.
  • Data cells use TD and do not require scope.

Table Editor

  • Use the Table Editor to:
    • Change cell types.
    • Set row and column scope.
    • Fix incorrect spanning.
    • Correct reading order.
  • If multiple cells have incorrect spans:
    • Select the cells.
    • Set the span value back to 1.
    • Reapply correct spans where needed.

Merging cells and Removing Empty Cells

  • To merge cells:
    1. Select cells in order.
    2. Press Ctrl + M
    3. Merge from right to left. 
  • To remove empty cells:
    1. Select the empty cells tags.
    2. Delete the tags.
    3. Run:
      • Cleanup and Skip Empty Cells.

 

Figure to Table Conversion

  • When charts contain important data:
    1. Convert the figure into a table instead of placing all information in alternative text.
    2. Select the chart.
    3. Choose Generate Table From Selection.
    4. Level the table tag up.
    5. Open the Table Editor.
    6. Correct:
      • Cell order
      • Headers
      • Scope
      • Linked cells

Note: This allows screen readers to navigate individual data points instead of listening to a long image description.

Redrawing Complex Tables

When table headers or structure are difficult to correct.
  1. Open the Table Editor.
  2. Redraw the table structure as needed.
  3. Insert cells where needed.
  4. Adjust cell spans.
  5. Add empty cells to align the table structure.
  6. Verify:
    • Header placement
    • Header scope
    • Linked cells
    • Reading order

Multi-Page Table Merge Process

When merging tables across pages:
  1. Select the first (top) table tag.
  2. Hold Ctrl or Shift and select the second table tag.
  3. Right-click and select Merge Tables.
  4. Select:
    1. Add Rows when combining tables vertically.
    2. Add Columns only when expanding the table horizontally.

Important Note: Selection order matters when merging tables. Always select the first table before the second table. 

After merging:
  1. Open the Table Editor.
  2. Verify:
    • Table structure
    • Header structure
    • Reading order
    • Linked headers

Full Table Cleanup

To remove empty cells:
  1. Select the table.
  2. Right-click.
  3. Select:
    • Cleanup
    • Full Table Cleanup

Lists

Lists should never be tagged as paragraphs.
  • Each list should contain:
    • List
    • List Item
    • Label
    • List Body
Note: Verify list order after generating list tags.

Creating List Tags

  • To create a list:
    1. Select the list content.
    2. Choose:
      1. Insert Tag
      2. Generate List Tag From Selection
    3. Level the list tag up to the root level.
    4. Run cleanup.
Note: A properly tagged list contains:
  • L (List)
    • LI (List Item)
      • Lbl (Label)
      • LBody (List Body)

Nested Lists

Nested lists contain additional lists inside list items.
  • Verify:
    • Sub-lists are inside the correct  LBody.
    • The list hierarchy matches the visual structure.

Multi-Page Lists

When a list continues across pages:
  1. Remediate each section separately.
  2. Merge the lists.
  3. Select the first list section before selecting the second.
  4. Verify the merged order.

Glossaries

Glossaries can be tagged as lists.
  • Terms should be placed in the Lbl tag.
  • Definitions should be placed in the LBody tag.

Ordered Lists

For numbered lists:
  • Verify list numbering values are correctly assigned in the Properties panel.
  • Do not tag numbered headings as lists.

List Navigation Tips

  • When reviewing list structure:
  • Use keyboard arrow keys to expand and collapse tags.
  • Right-click tags to expand all child tags.
  • Verify each list item contains:
    • Lbl
    • LBody

Links

Links should always contain: 
  • Link tag
  • Annotation
  • Hyperlink text
Links must be nested inside:
  • Paragraph
  • Table Cell
  • List Body

Link Tag Structure

  • Links must be contained within:
    • Paragraph
    • Table Header
    • Table Data Cell
    • List Body
  • A properly tagged link contains:
    • Link tag
      • Text
      • Annotation

Links Without Annotations

  • If a link has no annotation:
    1. Enable Untagged in Settings.
    2. Select the link.
    3. Insert a Link tag.
    4. Remove the unnecessary path tag.

Multiline Links

For links spanning multiple lines:
  • Keep annotation tags together.
  • Keep text tags together.
  • Maintain reading order.

Image Links

For images used as hyperlinks:
  • The Link tag should contain the Annotation.
  • The Figure tag should be below, but not inside, the Paragraph containing the Link.

Alternative Text

After running verification:
  1. Use the Fix Wizard to add alternative text to URLs or image links.
  2. Ensure each link contains:
    • Accessible link text or Annotation contents.

Forms

  • Each form control should receive its own Form tag.
  • Grouped controls (such as an address) should remain under one Paragraph tag.
  • Checkboxes and radio buttons require separate tags. 

Form Tag Structure

Form tags are inline tags and cannot be placed at the root level.
  • Structure:
    • Paragraph
      • Form
        • Text
        • Annotation

Standalone vs Grouped Forms

  • Standalone Forms
    • Use when fields are unrelated.
      • Example: Separate input fields that do not depend on each other.
  • Grouped Forms
    • Use when fields are connected.
      • Example:
        • Street address
        • City
        • State,
        • ZIP code

Radio Buttons

Some radio button groups require additional configuration in Acrobat to prevent users from selecting multiple options. .
  • In Acrobat:
    1. Open Prepare Form.
    2. Open the Properties for the first radio button.
    3. Ensure each radio button has:
      • A unique Name (for example, RadioButton1 and RadioButton2).
      • A unique value in the Options tab (for example, Yes and No).
        • Note: For Yes/No radio buttons, use Yes and No as the export values. 
Add the JavaScript:
  1. Select the Actions tab.
  2. Set the Trigger to Mouse Up.
  3. Set the Action to Run a JavaScript.
  4. Select Add, then paste the following script:
    • var A = this.getField("RadioButton1");
    • var B = this.getField(RaidioButton2");
    • If (A.value =="Yes") {
    • B.value = "Off";
    • }
  5. Select OK to save the script.
  6. Repeat these steps using the On Blue trigger. 
  7. Repeat the process for the second radio button using the opposite script:
    • var A = this.getField("RadioButton1");
    • var B = this.getField(RaidioButton2");
    • If (B.value =="No") {
    • A.value = "Off";
    • }

Note: Update the field names and values as needed. If the radio button group contains more than two options, modify the script to include the additional buttons. 

Verify the Radio Buttons:
  1. Save the PDF.
  2. Return to CommonLook.
  3. Verify the radio buttons are tagged correctly and appear in the correct reading order. 
  4. Test the form to confirm that only one radio button can be selected at a time.

Checkbox Tooltips

For groups of checkboxes:
  • Tag each checkbox separately
  • Include numbering in tooltips.
    • Example: 
      • 1 of 5
      • 2 of 5
      • 3 of 5

Table of Contents (TOC)

Each Table of Contents should contain:
  • TOC
  • TOCI
  • Reference
For linked TOCs:
  • Add hyperlinks before importing into CommonLook.
  • Artifact leader dots so screen readers do not read each individual dot.
  • Verify Reference alternative text.

Nested TOCs

For nested table of contents items:
  1. Insert another TOC tag beneath the correct TOCI Reference tag.
  2. Ensure the nested TOC is at the same level as the Reference tag above it.
  3. Verify the TOCI structure.

Fixing Split TOCIs

If a TOCI contains multiple Reference tags:
  1. Ctrl-click the Reference tags.
  2. Right-click.
  3. Select Merge Tags.
  4. Remove empty TOCI tags.
  5. Verify alternative text spacing.

Footnotes and Endnotes

  • Reference tag for the superscript number.
  • Note tag for the note itself
Each Note should contain:
  • Lbl
  • Span

Footnote and Endnote Structure

  • Paragraph
    • Reference 
    • Note
      • Lbl
      • Span

Creating Footnote Tags

  1. Select the superscript number or symbol.
  2. Insert a Reference tag.
  3. Select the entire footnote.
  4. Insert a Note tag.
  5. Add:
    • Lbl for the reference number.
    • Span for the footnote text.
Notes:
  • Footnotes may be moved closer to their reference point for easier screen reader navigation.
  • Endnotes cannot be moved.

Footnote and Endnote Structure

  • Structure:
    • Paragraph
    • Note
      • Lbl
      • Span

Keyboard Shortcuts

Use the following keyboard shortcuts to perform common tasks in CommonLook:
  • Ctrl + E = Clean up empty tags.
  • Ctrl + M = Merge selected table cells.
  • Ctrl + P = Level Up (move a tag up one level in the tag hierarchy).
  • Ctrl + Shift + Arrow Keys = Change the tag order. 
  • Ctrl + Click = Select multiple tags. 
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