Archiving - PDF/A

Version 6.2.0 · 2024-08-12

In this article

• What is PDF/A?
• limitations
• Create a PDF/A document
• PDF/A validation

This article describes how to create a PDF/A conforming document.

Note

PDF/A is under construction. The current implementation is in a very early state.

What is PDF/A?

PDF/A is an ISO-standardized version of the Portable Document Format (PDF) specialized for use in the archiving and long-term preservation of electronic documents. PDF/A differs from PDF by prohibiting features unsuitable for long-term archiving, such as font linking (as opposed to font embedding) and encryption.

Limitations

With PDFsharp you can create new documents that are PDF/A conforming.

• PDFsharp cannot convert an existing non-PDF/A document to a PDF/A conforming one.
• When you add a page or XObject from an external resource to your document, PDFsharp cannot ensure that this object is PDF/A conforming.
• PDFsharp cannot check whether an existing file is PDF/A conforming.

Create a PDF/A document

To tell PDFsharp that a document should be PDF/A conforming call the SetPdfA function. This is only a hack in this preview and may change in the future. You cannot set a specific PDF/A level.

var document = new PdfDocument();
document.SetPdfA();

One requirement of PDF/A is the creation of a tagged PDF. This is currently already implemented with PDF/UA because accessibility is also based on tagged PDF. PDF/A and PDF/UA are different things, but at the current stage of implementation you must create an UAManager.

// Get the manager for universal accessibility.
var uaManager = UAManager.ForDocument(document);

Use the StructureBuilder to tag text as e.g. an article with a paragraph. For more information see PDF/UA.

var font = new XFont("Verdana", 10, XFontStyleEx.Regular);
var pdfPage = document.AddPage();
var xGraphics = XGraphics.FromPdfPage(pdfPage);

// Get structure builder.
var sb = uaManager.StructureBuilder;
// Create article element in document.
sb.BeginElement(PdfGroupingElementTag.Article);
{
  // Create paragraph element.
  sb.BeginElement(PdfBlockLevelElementTag.Paragraph);
  var layoutRectangle = new XRect(0, 72, pdfPage.Width.Point, pdfPage.Height.Point);
  sb.End();
}
sb.End();

PDF/A validation

For validation if a PDF document is PDF/A conforming, we use veraPDF. veraPDF is an Open-Source tool developed by the PDF Association to analyze PDF documents and get detailed information about its PDF/A conformity. It can also be used for PDF/UA validation.