diff --git a/NAPS2.Sdk/Scan/Internal/Twain/TwainScanRunner.cs b/NAPS2.Sdk/Scan/Internal/Twain/TwainScanRunner.cs
index 8e8c8e1349..99ca6c2590 100644
--- a/NAPS2.Sdk/Scan/Internal/Twain/TwainScanRunner.cs
+++ b/NAPS2.Sdk/Scan/Internal/Twain/TwainScanRunner.cs
@@ -379,9 +379,11 @@ private void ConfigureSource(DataSource source)
                 break;
             case BitDepth.Grayscale:
                 source.Capabilities.ICapPixelType.SetValue(PixelType.Gray);
+                source.Capabilities.ICapBitDepth.SetValue(8);
                 break;
             case BitDepth.BlackAndWhite:
                 source.Capabilities.ICapPixelType.SetValue(PixelType.BlackWhite);
+                source.Capabilities.ICapBitDepth.SetValue(1);
                 break;
         }