diff --git a/Elwig/Dialogs/DeliveryConfirmationsDialog.xaml b/Elwig/Dialogs/DeliveryConfirmationsDialog.xaml
index 0cd521a..dbf9a2d 100644
--- a/Elwig/Dialogs/DeliveryConfirmationsDialog.xaml
+++ b/Elwig/Dialogs/DeliveryConfirmationsDialog.xaml
@@ -24,6 +24,8 @@
         <TextBox x:Name="TextElement" TextWrapping="Wrap" VerticalScrollBarVisibility="Visible" AcceptsReturn="True"
                  HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="200,10,10,10" Height="Auto"/>
 
+        <ProgressBar x:Name="ProgressBar" Margin="10,10,10,106" Height="27" Width="180"
+                     VerticalAlignment="Bottom" HorizontalAlignment="Left"/>
         <Button x:Name="TestButton" Content="Stichprobe" FontSize="14" Width="180" Margin="10,10,10,74" Height="27" Tag="Print" IsEnabled="False"
                 Click="TestButton_Click"
                 VerticalAlignment="Bottom" HorizontalAlignment="Left"/>
diff --git a/Elwig/Dialogs/DeliveryConfirmationsDialog.xaml.cs b/Elwig/Dialogs/DeliveryConfirmationsDialog.xaml.cs
index ba0764b..071c08a 100644
--- a/Elwig/Dialogs/DeliveryConfirmationsDialog.xaml.cs
+++ b/Elwig/Dialogs/DeliveryConfirmationsDialog.xaml.cs
@@ -93,8 +93,10 @@ namespace Elwig.Dialogs {
                 """)
                 .ToListAsync();
 
-            using var doc = await Document.Merge(list.Select(m => new DeliveryConfirmation(Context, Year, m, deliveries.Where(d => d.Delivery.MgNr == m.MgNr)))); ;
-            await doc.Generate();
+            using var doc = Document.Merge(list.Select(m => new DeliveryConfirmation(Context, Year, m, deliveries.Where(d => d.Delivery.MgNr == m.MgNr)))); ;
+            await doc.Generate(new Progress<double>(v => {
+                ProgressBar.Value = v;
+            }));
             Mouse.OverrideCursor = null;
 
             if (mode < 2) {
diff --git a/Elwig/Documents/Document.cshtml.cs b/Elwig/Documents/Document.cshtml.cs
index 3cbff9f..ab2a5ca 100644
--- a/Elwig/Documents/Document.cshtml.cs
+++ b/Elwig/Documents/Document.cshtml.cs
@@ -47,7 +47,7 @@ namespace Elwig.Documents {
             GC.SuppressFinalize(this);
         }
 
-        public static async Task<Document> Merge(IEnumerable<Document> docs) {
+        public static Document Merge(IEnumerable<Document> docs) {
             return new MergedDocument(docs);
         }
 
@@ -75,17 +75,21 @@ namespace Elwig.Documents {
             return await Html.CompileRenderAsync(name, this); ;
         }
 
-        public async Task Generate() {
+        public async Task Generate(IProgress<double>? progress = null) {
+            progress?.Report(0.0);
             if (this is MergedDocument m) {
                 var pdf = new TempFile("pdf");
                 var tmpHtmls = new List<TempFile>();
+                var n = 0;
                 foreach (var doc in m.Documents) {
                     var tmpHtml = new TempFile("html");
-                    await doc.Render();
                     await File.WriteAllTextAsync(tmpHtml.FilePath, await doc.Render(), Utils.UTF8);
                     tmpHtmls.Add(tmpHtml);
+                    n++;
+                    progress?.Report(50.0 * n / m.Documents.Count());
                 }
-                await Pdf.Convert(tmpHtmls.Select(f => f.FilePath), pdf.FilePath);
+                progress?.Report(50.0);
+                await Pdf.Convert(tmpHtmls.Select(f => f.FilePath), pdf.FilePath, new Progress<double>(v => progress?.Report(50.0 + v / 2)));
                 foreach (var tmp in tmpHtmls) {
                     tmp.Dispose();
                 }
@@ -94,10 +98,12 @@ namespace Elwig.Documents {
                 var pdf = new TempFile("pdf");
                 using (var tmpHtml = new TempFile("html")) {
                     await File.WriteAllTextAsync(tmpHtml.FilePath, await Render(), Utils.UTF8);
+                    progress?.Report(50.0);
                     await Pdf.Convert(tmpHtml.FilePath, pdf.FilePath);
                 }
                 _pdfFile = pdf;
             }
+            progress?.Report(100.0);
         }
 
         public void SaveTo(string pdfPath) {
diff --git a/Elwig/Documents/Pdf.cs b/Elwig/Documents/Pdf.cs
index fc7f07c..3eb704a 100644
--- a/Elwig/Documents/Pdf.cs
+++ b/Elwig/Documents/Pdf.cs
@@ -21,7 +21,7 @@ namespace Elwig.Documents {
         public static async Task Init(Action evtHandler) {
             var p = new Process() { StartInfo = new() {
                 FileName = WinziPrint,
-                Arguments = "-",
+                Arguments = $"-p -e utf-8 -d '{App.TempPath}' -",
                 CreateNoWindow = true,
                 UseShellExecute = false,
                 RedirectStandardInput = true,
@@ -32,20 +32,27 @@ namespace Elwig.Documents {
             evtHandler();
         }
 
-        public static async Task<IEnumerable<int>> Convert(string htmlPath, string pdfPath) {
-            return await Convert(new string[] { htmlPath }, pdfPath);
+        public static async Task<IEnumerable<int>> Convert(string htmlPath, string pdfPath, IProgress<double>? progress = null) {
+            return await Convert(new string[] { htmlPath }, pdfPath, progress);
         }
 
-        public static async Task<IEnumerable<int>> Convert(IEnumerable<string> htmlPath, string pdfPath) {
+        public static async Task<IEnumerable<int>> Convert(IEnumerable<string> htmlPath, string pdfPath, IProgress<double>? progress = null) {
             if (WinziPrintProc == null) throw new InvalidOperationException("The WinziPrint process has not been initialized yet");
+            progress?.Report(0.0);
             await WinziPrintProc.StandardInput.WriteLineAsync($"{string.Join(';', htmlPath)};{pdfPath}");
-            var line = await WinziPrintProc.StandardOutput.ReadLineAsync() ?? throw new IOException("Invalid response from WinziPrint");
-            if (line.StartsWith("error:")) {
-                MessageBox.Show(line[6..].Trim(), "Fehler", MessageBoxButton.OK, MessageBoxImage.Error);
-                return Array.Empty<int>();
+            while (true) {
+                var line = await WinziPrintProc.StandardOutput.ReadLineAsync() ?? throw new IOException("Invalid response from WinziPrint");
+                if (line.StartsWith("error:")) {
+                    MessageBox.Show(line[6..].Trim(), "Fehler", MessageBoxButton.OK, MessageBoxImage.Error);
+                    return Array.Empty<int>();
+                } else if (line.StartsWith("progress:")) {
+                    var parts = line[9..].Trim().Split('/').Select(int.Parse).ToArray();
+                    progress?.Report(parts[0] / (double)parts[1]);
+                } else if (line.StartsWith("success:")) {
+                    var m = Regex.Match(line, @"\(([0-9, ]+)\)");
+                    return m.Groups[1].Value.Split(", ").Select(n => int.Parse(n));
+                }
             }
-            var m = Regex.Match(line, @"\(([0-9, ]+)\)");
-            return m.Groups[1].Value.Split(", ").Select(n => int.Parse(n));
         }
 
         public static void Show(TempFile file, string title) {
diff --git a/Elwig/Windows/MemberAdminWindow.xaml.cs b/Elwig/Windows/MemberAdminWindow.xaml.cs
index 353ba54..9bfbae3 100644
--- a/Elwig/Windows/MemberAdminWindow.xaml.cs
+++ b/Elwig/Windows/MemberAdminWindow.xaml.cs
@@ -317,7 +317,7 @@ namespace Elwig.Windows {
                         .ThenBy(m => m.MgNr);
                     break;
             }
-            using var doc = await Document.Merge((await members.ToListAsync()).Select(m => new Letterhead(m)));
+            using var doc = Document.Merge((await members.ToListAsync()).Select(m => new Letterhead(m)));
             await doc.Generate();
             Mouse.OverrideCursor = null;
             if (App.Config.Debug) {