3-Heights™ PDF to PDF/A Converter – create and sign a PDF/A from a PDF source

The 3-Heights™ PDF to PDF/A Converter is a component for converting PDF documents into the PDF/A format for long-term archiving. This component is both robust and scalable, making it suitable for integration in various processes such as standardization, quality assurance and archive migration.


Convert PDF documents to PDF/A

Embed & Sign

Add PDF/A-conform long-term digital signature and embed metadata

Digital Archive

Integrate into archiving systems

Product illustration 3-Heights™ PDF to PDF/A Converter

PDF to PDF/A Converter - features

  • Convert PDF documents to PDF/A-1, PDF/A-2, PDF/A-3
    • Support for all PDF/A conformance levels
    • Make color spaces device-independent, e.g. by embedding ICC profile or setting an output intent
    • Embed and subset fonts
    • Colorants management (PDF/A-2 and later)
    • Recover corrupt documents
    • Repair corrupt data such as embedded font programs or images
    • Remove transparency (PDF/A-1 only)
    • Remove malicious content such as attached files (PDF/A-1 and PDF/A-2) and JavaScript actions
    • Remove multimedia content such as video and sound
    • Conversion of embedded and attached files (PDF/A-2 and later)
    • Repair metadata and make them consistent
  • Conversion process control
    • Pre- and post-validation
    • Conversion reporting
    • Write the application log to a log file
    • Automatically determine optimal conformance based on input file (optional)
    • Enables sophisticated error handling
  • Digital signatures, PDF/A-conform
    • Apply PAdES-LTV (Long Term Validation) signatures
    • Embedded trust chain, time-stamp and revocation information (OCSP, CRL)
    • Various types of cryptographic providers
      • Windows certificate store
      • Hardware such as hardware security module (HSM), smart cards, and USB tokens
      • Online signature services
        • 3-Heights™ Signature Creation and Validation Service
        • SwissSign Digital Signing Service
        • SwissSign SuisseID Signing Service
        • QuoVadis sealsign
        • Swisscom All-in Signing Service
        • GlobalSign Digital Signing Service
    • Mass signing of documents
    • Add an optional visual appearance of the signature (page, size, color, position, text, background image, etc.)
  • Read input from and write output document to file or memory
  • Read encrypted input files
  • Enhance output file
    • Set metadata
    • Linearization for fast web view
    • Use PDF file compression features (PDF/A-2 and later)
  • Text recognition using OCR engine (optional)
    • Replace old OCR text or skip images with existing OCR text
    • Set the OCR language and options
    • Deskew and de-noise images
    • Detect barcodes
    • List OCR plug-ins
  • Add embedded files (PDF/A-2) and associated files (PDF/A-3)
  • Embedded XML invoice data conforming to the ZUGFeRD specification (PDF/A-3)


  • Standards:
    • ISO 19005-1 (PDF/A-1)
    • ISO 19005-2 (PDF/A-2)
    • ISO 19005-3 (PDF/A-3)
    • ISO 32000-1 (PDF 1.7)
    • ISO 32000-2 (PDF 2.0)
    • PAdES (ETSI EN 319 142) signature levels B-B, B-T, CMS
    • Legacy PAdES (ETSI TS 103 172) Part2 and Part4 (Long Term Validation, LTV)
    • Cryptographic Suites (ETSI TS 119 312)
    • ZUGFeRD
  • Quality assurance: veraPDF test corpus and Isartor test suite

Supported formats

Input formats

  • PDF 1.0 to 1.7
  • PDF 2.0

Output formats

  • PDF/A-1a*, PDF/A-1b
  • PDF/A-2a*, PDF/A-2b, PDF/A-2u
  • PDF/A-3a*, PDF/A-3b, PDF/A-3u

*) The input file must fulfill the relevant conditions for PDF/A creation.

Areas of use - PDF conversion to PDF/A

Incoming mail

All incoming PDF documents can be converted directly to PDF/A for long-term archiving. Documents that cannot be converted can be rejected as soon as they are received by email. This increases process quality and reduces the need for subsequent quality controls.


The converter processes documents from all corporate business areas during archiving. It quickly and easily converts documents worthy of retention into PDF/A and verifies conformity of the result with the ISO standard. It therefore acts as a gatekeeper, ensuring that only conform files find their way into business processes or a long-term archive.

Other areas of use

  • Standardization
  • Quality assurance
  • Conformance with legal requirements

#Sample 1 - Convert a PDF document to PDF/A

Convert a PDF document to PDF/A with given conformance and conversion options.

using System;
using Pdftools.Pdf2Pdf;
using Pdftools.Pdf;

namespace Pdf2PdfAConverterSamples
    class ConvertToPdfASample
        /// <summary>
        /// Converts a given PDF document to PDF/A
        /// </summary>
        /// <param name="inFilePath">Path to PDF document to be converted</param>
        /// <param name="outFilePath">Path to resulting PDF/A</param>
        /// <param name="conformance">Conformance the converted file should conform to</param>
        /// <param name="allowDowngrade">Allow downgrade to another PDF/A level if requested conformance cannot be met</param>
        /// <param name="allowUpgrade">Allow upgrade to another PDF/A version if requested conformance cannot be met</param>
        public static void convertDocumentToPdfA(string inFilePath, string outFilePath, PDFConformance conformance, bool allowDowngrade, bool allowUpgrade, string outputIntent="", int errorMask=-1)
            using (Pdf2Pdf conv = new Pdf2Pdf())
                string logFilePath = outFilePath.Replace(".pdf", "") + "-log.txt";

                // 1. Configure the converter
                conv.Conformance = conformance;
                conv.AllowDowngrade = allowDowngrade;
                conv.AllowUpgrade = allowUpgrade;
                conv.ReportSummary = true;

                if (!string.IsNullOrWhiteSpace(outputIntent)) conv.OutputIntentProfile = outputIntent;
                if (errorMask >= 0) conv.ConversionErrorMask = errorMask;

                // 2. Convert document according to parameters set
                if (!conv.Convert(inFilePath, String.Empty, outFilePath, logFilePath))
                    if (conv.ErrorCode == PDFErrorCode.PDF_E_CONVERSION)
                        Console.WriteLine(conv.ErrorCode + ": " + conv.ErrorMessage);

                    Console.WriteLine("See '" + logFilePath + "' for details.");

        /// <summary>
        /// Prints given conversion errors
        /// </summary>
        /// <param name="conversionErrors">Encoded conversion error flags</param>
        public static void printConversionErrors(int conversionErrors)
            Console.WriteLine("File converted to PDF/A, but conversion errors were encountered. Please check the resulting file manually.");
            Array errors = Enum.GetValues(typeof(PDFConversionError));
            foreach (PDFConversionError err in errors)
                if (((int)err & conversionErrors) != 0)
                    Console.WriteLine("* " + err.ToString());
pdf2pdf -v -rs -cl pdfa-2a in.pdf out.pdf
# Convert in.pdf to PDF/A-2a
# -v: verbose mode
# -rs: report summary
# -cl pdfa-2a: convert to PDF/A-2a

pdf2pdf -v -rs -cl pdfa-2a -ad in.pdf out.pdf
# Convert in.pdf to PDF/A-2a, but allow automatic downgrade of conformance level (to e.g. PDF/A-2b) if requested level cannot be met
# -ad: allow automatic downgrade

pdf2pdf -v -rs -cl pdfa-1b -au in.pdf out.pdf
# Convert in.pdf to PDF/A-1b, but allow automatic upgrade of PDF/A version, if target standard does not support certain elements of input document (e.g. from PDF/A-1 to PDF/A-2)
# -au: allow automatic upgrade
Functionality graphic 3-Heights™ PDF to PDF/A Converter

PDF/A and searchability at the Federal Ministry of Justice

Thanks to the provision of PDF Tools AG's 3-Heights™ PDF to PDF/A Converter and ABBYY’s OCR engine as central services, each document can now be converted to PDF/A and made electronically searchable across the justice system. The PDF/A Converter’s Java API allowed the BRZ to integrate the product into its systems quickly and easily.

PDF/A conversion with OCR recognition for Volkswagen Foundation’s document management

By integrating the 3-Heights™ components, the Volkswagen Foundation achieved a standardization of the different PDF variants in their DMS. As well, the conversion of different image formats into full-text indexed PDF documents is possible.

Further product details

The 3-Heights™ PDF to PDF/A Converter first analyzes the input file based on the level of conformity (Level A, B or U). Conversion to the highest possible level of conformity is then carried out with the aid of the result from the analysis. There is also an option to carry out an analysis of the output document.

The conversion process embeds missing fonts and optimizes them by forming subsets. Matching color profiles are created for device-dependent color spaces. An output intent is created where necessary. Prohibited content such as JavaScripts and unnecessary content is removed and required content completed where possible. The file is reformatted during conversion and safe repairs are carried out.

Digital signing: The application of an advanced electronic corporate signature or personal Qualified Electronic Signature (QES) guarantees the authenticity and integrity of archived documents. Embedding a time stamp and revocation information keeps the digital signature verifiable in the long-term.

Further information about PDF/A

PDF Expert blog - the caveats of assembling PDF/A documents

The caveats of assembling PDF/A documents

Assembling PDF documents from various sources is a crucial part of an output management system. And, as the document needs to be archived in most cases, it should conform to the PDF/A standard. Is there a way to assemble a document and accomplish PDF/A conformance in one step?

PDF Expert Blog - Convert invoice documents to the ZUGFeRD data format

Converting invoice documents to the ZUGFeRD data format

XML or PDF? That's one of the most heard questions when it comes to invoice document formats. XML is the preferred format for machines whereas PDF is the format for humans. But why not have the cake and eat it? With ZUGFeRD you can have both documents in one file.


  • What is ZUGFeRD?
  • Where is ZUGFeRD used and when does it make sense?
  • What do you have to keep in mind?
  • How does PDF Tools AG support ZUGFeRD?