[gs-devel] Producing a document in pdf x/1a:2001 format.

Ken Sharp ken.sharp at artifex.com
Thu Sep 17 08:20:42 PDT 2009


At 08:37 17/09/2009 -0400, you wrote:

>Is there a way to produce a pdf file via Ghostscript in the pdf
>x/1a:2001 format? It is similar but not identical to pdf 1.3. But LSI
>insists on the x/1a format.

Please see the documentation:

/gs/doc/ps2pdf.htm "Section 8 Producing a PDF/A document"

This will produce a PDF/A1-b file as defined by the ISO standard. It is not 
really possible to produce a PDF/A1-a file, as this encompasses 'tagged 
PDF' (See ISO 19005-1:2005 Section 6.8). Tagged PDF embeds additional 
metadata in the PDf file which describes the structure of the document 
(headers, footers, body text, headlines etc).

PostScript files do not supply this information (nor do PDF files which are 
not already tagged), and the specification quite specifically states 
(Section 6.8.1) that writers should not add information merely to meet 
conformance criteria:

"PDF/A-1 writers should not add structural or semantic information that is 
not explicitly or implicitly present in the source material solely for the 
purpose of achieving conformance. Examples of such information are 
structure hierarchy, natural language specification, alternative 
descriptions, non-textual annotations, replacement text and expansions of 
abbreviations and acronyms."

That said I am aware that this is the 2005 version of the specification, 
and that Adobe Acrobat Distiller can write the lesser 2001 format. Since 
the first edition of the ISO standard is 2005, I assume the 2001 version 
was an earlier non-ISO approved specification. Are you sure you mean the 
2001 standard ?

There seems no real reason to insist on tagged PDF for a Print On Demand 
application, since text extraction, editing and reflow would seem unlikely 
requirements. However you could try simply editing the XML metadata and 
declaring the file as a PDF/A1-a file, it might even work.

We currently have no plans to extend support to PDF/A1-a, for the stated 
reasons.

                 Ken


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