For each PDF/A-1 validation issue we try to explain what it means and, if possible how to resolve it. For a more technical explanation of the issue we quote the related section of the ISO 19005-1 PDF/A Specification.
The key <<AP>> is required for PDF/A-1b The key <<N>> is required for PDF/A-1b Value "true" is prohibited for the key <<NeedAppearances>> The key <<A>> is prohibited for PDF/A-1b
6.9 - ISO 19005-1 PDF/A Specification:
The intent of the requirements of this subclause is to ensure that there is no ambiguity about the rendering of form fields.
A conforming reader shall not use form fields to change the rendered representation of the page or the content of the file at any time. A Widget annotation dictionary or Field dictionary shall not contain the A or AA keys.
The NeedAppearances flag of the interactive form dictionary shall either not be present or shall be false.
Every form field shall have an appearance dictionary associated with the field's data. A conforming reader shall render the field according to the appearance dictionary without regard to the form data.
NOTE: Requiring an appearance dictionary ensures the reliable rendering of the form.