When creating or repairing a PDF for PDF/UA compliance, what is the best practice for complying with Matterhorn Protocol failure conditions 16-001 - "List is an ordered list, but no value for the ListNumbering attribute is present"; and 16-002 - "List is an ordered list, but the ListNumbering value is not one of the following: Decimal, UpperRoman, LowerRoman, UpperAlpha, LowerAlpha"? I have been unable to find any PDF/UA example that uses the ListNumbering attribute - at least, as far as I can tell. Where in the List tag structure does the attribute go and how do I set it correctly?
By searching through the code using Notepad++ I was able to find that the ListNumbering attribute is used in the new Matterhorn Protocol 1.01 PDF (http://www.pdfa.org/wp-content/uploads/2014/03/MatterhornProtocol_1-011.pdf), example: <</ListNumbering/Disc/O/List>>. I have not found it in any other document, even those that claim PDF/UA compliance and have lists. And, I still do not find any way to access or set the attribute using Acrobat XI.
A kind expert, Samuel H., CTO, xyMedia GmbH, shared the solution in another forum. I am posting it here in case others may benefit ...
You can set this attribute in Acrobat as following:
1. Right click on the L tag in the "Tags" panel.
2. Choose "Properties...".
3. Click on "Edit Attribute Objects".
4. Click "New Item".
5. Open the /Attribute Object 1 <<Dictionary>> that is created.
6. You should find an owner ("/O") key with a value of "Layout". Change "Layout" to "List" via Button "Change Item".
7. Select "/Attribut Object 1" (or the one that has been created in step 4).
8. Click "New Element".
9. Choose value type: "Name".
10. Enter key: "ListNumbering"
11. Enter the value. It must be one of them which are specified in the specification: None, Disc, Circle, Square, Decimal, UpperRoman, LowerRoman, UpperAlpha, or LowerAlpha.
12. Click "OK" twice and then "Close"