PAC 2 Error
Alternative description missing for an annotation
Category
PDF/UA > Logical Structure > Alternative Descriptions > Alternative descriptions for annotations
Failure Condition
Matterhorn Protocol Checkpoint 28-012: A link annotation does not include an alternate description in the Contents Key.
Update: If you are using Acrobat Pro DC, there is an easier fix that will copy the the link text and apply it to the Contents key – so, not really an “alternate” description, but for links with meaningful text or for internal links like in a Table of Contents, it is a much less time-consuming solution …
Tools > Print Production > Preflight > At the top of the Preflight dialogue, select Acrobat Pro DC 2015 Profiles in the drop down box > Under PDF/UA, select Fix problems in PDF tagging structure. This will add the Contents key to link tags that are missing it, and will apply few other fixes if needed.
Suggestion
For older versions of Acrobat Pro, or to apply a specific alternate Description …
In the PAC 2 test report, click the error to see the location of the link in the document. In the Tags pane in Acrobat Pro, right-click the Link tag and select Properties. On the Tag tab of the Object Properties dialog, click the Edit Tag button. In the Tag Element dialog, expand items and drill down to the “/Obj <<Dictionary>>” item (I usually find it under “/K [Array]”; then “[0] <<Dictionary>>”. Select “/Obj <<Dictionary>>” then click the New Item button. In the Add Key and Value dialog, enter Contents in the Key field, change the Value Type to String, and enter a meaningful alternate description in the Value field. For external links, a good practice is to use a description that matches the Title property of the target page. For internal links such as those in a Table of Contents, it may make sense to simply use the text of the link itself.
Note: In the case of a link that is split across a line break such that there are two Link-OBJR objects nested under the Link tag, you should find two “[#] <<Dictionary>>” items, each with a “/Obj <<Dictionary>>”, both of which will need a Contents key with an alternate description.
Video version of this suggestion:
