A PDF/A-1 file must be identified as such by the presence of a certain entry in its XMP document metadata. In order to be able to retrieve this entry reliably, it is essential that all syntactical requirements for storing metadata are followed precisely. In early implementations of PDF/A tools this was not always the case due to several reasons.
Note: The information provided in this TechNote has been published by ISO as PDF/A-1 Technical Corrigendum 1 (see ) in April 2007. However, this TechNote predates Technical Corrigendum 1 and we still provide it for consistency.