# PDF/A

> Archive WPF documents as PDF/A-3a with StreamType.AdobePDFA: embeddable fonts, AdaptFont logging, PDF/A rules, folder conversion and checking in Acrobat.

- **Product:** TX Text Control .NET for WPF
- **Section:** Documentation
- **Kind:** Topic
- **Path:** TX Text Control .NET for WPF > PDF Processing > PDF/A
- **2721 words**
- **Web URL:** https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/pdf-a/
- **LLMs URL:** https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/pdf-a/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/pdf-a/llms-full.txt

---

When documents from a WPF application go into an archive, such as signed contracts, invoices or records that must be kept for years, PDF/A is the format to save them in. The `TextControl` of a window and a `ServerTextControl` write it with `StreamType.AdobePDFA`. Before the save succeeds, the document has to follow the rules of the standard, above all for its fonts.

[Create a PDF/A Document](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/getting-started/pdf/create/#create-a-pdf-a-document) in Getting Started saves a first PDF/A file from the editor and one from a copy, without changing the editor's font settings. PDF/A requires the Enterprise edition; see [Editions and Feature Availability](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/overview/editions/llms-full.txt).

### What PDF/A Is

PDF/A, ISO 19005, is the standard for the long-term archiving of electronic documents. Everything needed to display a PDF/A file is inside it, including its fonts. Audio, video, JavaScript, other executable content and encryption aren't allowed.

Of the parts of the standard, PDF/A-3 allows embedded files of any format, for example the XML data of an electronic invoice. The conformance level "a" adds a logical structure with tags for assistive technologies, so a PDF/A-3a document is accessible as well.

### What TX Text Control Writes

- **Since version 34.0,** `StreamType.AdobePDFA` saves PDF/A-3a. The tagged structure is also what PDF/UA requires, so a document can conform to PDF/A-3a and PDF/UA at the same time, as [Create an Accessible PDF (PDF/UA)](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/creation-conversion/#create-an-accessible-pdf-pdf-ua) describes.
- **Before version 34.0,** TX Text Control wrote PDF/A-1b, and since version 29.0, documents with attachments as PDF/A-3b.

According to [StreamType](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol/streamtype/enumeration/llms-full.txt), `AdobePDFA` is a format for saving only, and only complete documents can be saved with it. To load a PDF/A file, use `StreamType.AdobePDF`. Any document the window can show can be saved as PDF/A, whether it was typed, loaded from DOCX, RTF or HTML, merged from a template or imported from a PDF.

### The Rules of PDF/A

TX Text Control applies the rules of the standard when it saves. For your code, they mean:

- **Embeddable fonts only.** [FontSettings.EmbeddableFontsOnly](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol/fontsettings/embeddablefontsonly-property/llms-full.txt) must be `true` before the save; the default is `false`. Fonts that can't be embedded are then replaced, as [Font Embedding and Substitution](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/fonts/#restrict-the-fonts-of-a-document) explains.
- **No passwords.** Encryption isn't allowed, so a PDF/A document has no user password, master password or permissions.
- **No JavaScript.** [SaveSettings.DocumentLevelJavaScriptActions](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol/savesettings/documentleveljavascriptactions-property/llms-full.txt) is ignored for PDF/A.
- **Pages from the page layout.** The technical article on PDF import and export in the reference lists [ViewMode](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol-wpf/textcontrol/viewmode-property/llms-full.txt) `PageView` as the first step, so that the PDF gets the page size of the document. In `FloatingText` mode, page size and margins are ignored.
- **Attachments are allowed** in PDF/A-3, as [Attachments](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/attachments/llms-full.txt) describes.

### Save the Window's Document as PDF/A

Add a button with the handler `ArchiveButton_Click` to *MainWindow.xaml*. The following code in *MainWindow.xaml.cs* saves the document of `textControl1` as PDF/A and writes each replaced font to the **Output** window of Visual Studio:

```csharp
private void ArchiveButton_Click(object sender, RoutedEventArgs e)
{
    // Report every font that is replaced
    textControl1.FontSettings.AdaptFontEvent = true;
    textControl1.AdaptFont += TextControl1_AdaptFont;

    // Only fonts that can be embedded; all others are replaced
    textControl1.FontSettings.EmbeddableFontsOnly = true;

    textControl1.ViewMode = ViewMode.PageView;

    try
    {
        textControl1.Save("contract-archive.pdf", StreamType.AdobePDFA,
            new SaveSettings() { DocumentTitle = "Service Contract" });
    }
    finally
    {
        textControl1.AdaptFont -= TextControl1_AdaptFont;
    }
}

private void TextControl1_AdaptFont(object sender, AdaptFontEventArgs e)
{
    Debug.WriteLine(e.FontName + " is replaced with " + e.AdaptedFontName);
}
```

The file needs `using System.Diagnostics;`, `using System.Windows;` and `using TXTextControl;`. The code works as follows:

- Restricting the fonts is one of the moments the [AdaptFont](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol-wpf/textcontrol/adaptfont-event/llms-full.txt) event occurs, so the handler is connected first. [Choose the Replacement Fonts](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/fonts/#choose-the-replacement-fonts) explains the event and how to pick the replacement yourself.
- `ViewMode` is an enumeration of the `TXTextControl` namespace, although the property belongs to the WPF `TextControl`.
- The [SaveSettings](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol/savesettings/llms-full.txt) give the archived document a title.

`EmbeddableFontsOnly` remains `true` after the save, and the user continues with the replaced fonts. To avoid that, save the PDF/A file from a copy, as [Create a PDF/A Document](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/getting-started/pdf/create/#create-a-pdf-a-document) shows.

### Archive a Folder of Documents

The following handler converts every DOCX file of a folder the user picks into PDF/A with a `ServerTextControl` and lists the files whose fonts can't be embedded:

```csharp
private void ArchiveFolderButton_Click(object sender, RoutedEventArgs e)
{
    OpenFolderDialog dialog = new OpenFolderDialog();

    if (dialog.ShowDialog(this) != true)
    {
        return;
    }

    List<string> failed = new List<string>();

    foreach (string file in Directory.GetFiles(dialog.FolderName, "*.docx"))
    {
        using (ServerTextControl tx = new ServerTextControl())
        {
            tx.Create();

            // Set before Load, so that it applies to the fonts of the document
            tx.FontSettings.EmbeddableFontsOnly = true;

            tx.Load(file, StreamType.WordprocessingML);

            try
            {
                tx.Save(System.IO.Path.ChangeExtension(file, ".pdf"), StreamType.AdobePDFA);
            }
            catch (FilterException exception) when
                (exception.Reason == FilterException.FilterError.NonEmbeddableFont)
            {
                failed.Add(System.IO.Path.GetFileName(file));
            }
        }
    }

    if (failed.Count > 0)
    {
        MessageBox.Show(this, "Fonts that can't be embedded:\n" + string.Join("\n", failed), "PDF/A");
    }
}
```

The handler also needs `using System.IO;` and `using Microsoft.Win32;`, the namespace of `OpenFolderDialog`. A document that still contains a font that can't be embedded throws a [FilterException](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol/filterexception/llms-full.txt) with the [Reason](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol/filterexception/reason-property/llms-full.txt) `NonEmbeddableFont`. [A Document Can't Be Saved as PDF/A](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/troubleshooting/fonts/#a-document-can-t-be-saved-as-pdf-a) lists the messages and what to do.

### Check the Result

Adobe Acrobat lists the standards a PDF claims to conform to. For a document saved with `AdobePDFA` in version 34.0, these are PDF/A-3A and PDF/UA-1:

![Adobe Acrobat with a PDF saved by TX Text Control, a note that the file claims PDF/A compliance, and the Standards panel listing PDF/A-3A and PDF/UA-1.](https://docs.textcontrol.com/assets/img/tx-text-control-dotnet-wpf/pdf-a-conformance.978f21eb.webp)

Acrobat opens the file read-only to prevent changes, as the note at the top says. The panel shows what the file claims; its status is "not yet verified" until a validation checks it. PDF/A conformance is validated with a PDF/A validator such as veraPDF. Text Control's `TXTextControl.PDF.Validation` package validates PDF/UA, the accessibility side, and reports only whether a PDF/A declaration exists, as [Validate the Accessible PDF](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/creation-conversion/#validate-the-accessible-pdf) describes.

### Electronic Invoices and Signatures

- **Electronic invoices.** ZUGFeRD and Factur-X invoices are PDF/A-3 documents that carry the invoice data as embedded XML. [PDF Examples](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/examples/pdf/llms-full.txt) lists samples, and [Attachments](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/attachments/llms-full.txt) shows how to embed the XML.
- **Signatures.** [SaveSettings.DigitalSignature](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/reference/txtextcontrol/savesettings/digitalsignature-property/llms-full.txt) signs a PDF/A document while it is saved, as [Signing PDF Documents](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/digital-signatures/signing/llms-full.txt) describes.

The blog article [PDF/UA vs. PDF/A-3a: Which Format Should You Use for Your Business Application?](https://www.textcontrol.com/blog/2025/10/24/pdf-ua-vs-pdf-a-3a-which-format-should-you-use-for-your-business-application/) compares the two standards.

### Next Steps

- [Font Embedding and Substitution](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/fonts/llms-full.txt): choose the fonts that replace others.
- [Attachments](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/attachments/llms-full.txt): embed XML and other files in PDF/A-3 documents.
- [Digital Signatures](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/digital-signatures/llms-full.txt): sign archived documents.

---

## Nearby

- **Previous:** [PDF Import and Its Limitations](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/import/llms-full.txt)
- **Next:** [Font Embedding and Substitution](https://docs.textcontrol.com/tx-text-control-dotnet-wpf/pdf/fonts/llms-full.txt)