Due to an unknown reason Adobe Acrobat 9 duplicates all meta data keywords—if there are more than one—during a PDF/A conversion (e.g. to PDF/A-1b). Acrobat puts the existing group of keywords between “quotation marks” and adds a copy after a semicolon separator. This problems appears even if “Apply fixups” is disabled.

Example

The XMP samples just contain parts that are relevant to keywords, everything else was left out (but can be found in the sample PDF files).

Keywords before conversion:

<?xpacket begin="" id="xxx"?>
 <x:xmpmeta x:xmptk="Adobe XMP Core 4.2.1-c041 52.342996, 2008/05/07-20:48:00 ">
  <rdf:RDF>
   <rdf:Description rdf:about="">
    <dc:subject>
     <rdf:Bag>
       <rdf:li>keyword1</rdf:li>
       <rdf:li>keyword2</rdf:li>
     </rdf:Bag>
    </dc:subject>
   </rdf:Description>
   <rdf:Description rdf:about="">
    <pdf:Producer>Adobe Acrobat 9.0.0</pdf:Producer>
    <pdf:Keywords>keyword1; keyword2</pdf:Keywords>
   </rdf:Description>
  </rdf:RDF>
 </x:xmpmeta>
<?xpacket end="w"?>

• Sample file: Keywords before conversion [PDF]

Keywords after conversion:

<?xpacket begin="" id="xxx"?>
 <x:xmpmeta x:xmptk="Adobe XMP Core 4.2.1-c041 52.342996, 2008/05/07-20:48:00 ">
  <rdf:RDF>
   <rdf:Description rdf:about="">
    <dc:subject>
     <rdf:Bag>
      <rdf:li>keyword1; keyword2</rdf:li>
      <rdf:li>keyword1; keyword2</rdf:li>
     </rdf:Bag>
    </dc:subject>
   </rdf:Description>
   <rdf:Description rdf:about="">
    <pdf:Producer>Adobe Acrobat 9.0.0</pdf:Producer>
    <pdf:Keywords>"keyword1; keyword2"; "keyword1; keyword2"</pdf:Keywords>
   </rdf:Description>
  </rdf:RDF>
 </x:xmpmeta>
<?xpacket end="w"?>

• Sample file: Keywords after conversion [PDF]

Details

Affected functions:

• Preflight > ”Convert to PDF/A...“
• File > Export > PDF/A

Tested versions:

• Windows
  • Adobe Acrobat 9.0.0
  • Adobe Acrobat 9.1.2

• Mac
  • not tested yet
    

Status:

• Reported: Yes
• Replied: Yes
• Fixed: ?

Workaround

• Remove duplicated keywords manually (CTRL+D) or use an external tool for editing/replacing the XMP meta data—scripting within Acrobat (doc.info.keywords, doc.metadata) won't do the job.

Links

• Adobe Forums: “Acrobat 9: Keywords are duplicated on PDF/A conversion“

Comments

1. Not fixed in Adobe Acrobat 9.1.2

   — Frank Spangenberg at June 26, 2009 [#]