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How can I generate PDF/A files?

Dynamic Web TWAIN supports exporting documents as PDF/A starting from version 19.3. PDF/A is an archival format designed for long-term preservation. The following variants are supported:

Supported PDF/A Versions

Recommendation: For most use cases, we recommend using pdf/a-2b. It offers better compression support, fewer limitations, and higher compatibility with modern PDFs while still meeting archival requirements.

Licensing Requirements

Dynamic Web TWAIN does not require any add-on license to export or generate PDF or PDF/A files. However, PDF Rasterizer add-on would be required when loading a PDF/PDF-A file that contains text or vector graphics.

You can programmatically check whether a file needs rasterization using IsRasterizationRequired():

DWTObject.Addon.PDF.IsRasterizationRequired(path); // returns true or false

Behavior and Defaults

• If you do not set pdfaVersion, the export uses standard PDF format (non-PDF/A).

• The version setting only applies when exporting standard (non-PDF/A) PDFs. Once pdfaVersion is set, version is ignored — the underlying PDF version is fixed entirely by the PDF/A variant:

  • pdf/a-1b → PDF 1.4
  • pdf/a-2b / pdf/a-3b → PDF 1.7

How to Export as PDF/A

Configure PDF output using Write.Setup() before calling any save function.

DWTObject.Addon.PDF.Write.Setup({
    version: "1.5",          // [optional] Only used for standard (non-PDF/A) PDFs; ignored once pdfaVersion is set
    pdfaVersion: "pdf/a-2b"  // "pdf/a-1b", "pdf/a-2b" (since v19.3), or "pdf/a-3b" (since v19.4)
});

After configuring pdfaVersion, all APIs that output PDF files will automatically generate PDF/A-compliant PDFs. This includes, but is not limited to:

• Save APIs like: SaveAsPDF(), SaveSelectedImagesAsMultiPagePDF(), SaveAllAsPDF()

• Conversion APIs like: ConvertToBlob(), ConvertToBase64()

• Upload APIs like: HTTPUpload(), FTPUpload(), httpUploadBlob()

• OCR Output APIs like: SaveToPath(), SaveAsBase64(), SaveAsBlob()

Original post creation date: Dec 01, 2021

Last modified date: Jul 30, 2026