Actual Text – Alt Text – Expansion Text – Contents Key

PAC 2 Error

Errors involving alternative text can include:

  • Alternative text missing for Figure structure element; and
  • Alternative description missing for an annotation;

Other errors involving alternative text require human inspection.


PDF/UA > Logical Structure > Alternative Descriptions

Failure Condition

Matterhorn Protocol Checkpoint 13: Graphics


  • The Actual Text attribute is used for text rendered in a way that a screen reader can not interpret – such as a graphic or a character that does not map to Unicode. Actual Text is short, frequently just one character, and can be used inline, for example as part of a paragraph or even part of a word. Examples include a drop cap or a non-standard list bullet.
  • The Alt Text attribute is a description of a figure that conveys information. It can be detailed, and as long as necessary to convey the same meaning as the figure.
  • Expansion Text is used to define an acronym or jargon term on first use.
  • The Matterhorn Protocol requires an alternate description in the Contents Key of every Link tag. For links to web pages, a good practice is to set the value of the Contents Key to the title attribute of the target page. The value type is always String.

Example PDF

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