diff --git a/src/NTwain/Data/TwainValues.cs b/src/NTwain/Data/TwainValues.cs
index 3c4bea3..5963678 100644
--- a/src/NTwain/Data/TwainValues.cs
+++ b/src/NTwain/Data/TwainValues.cs
@@ -1103,7 +1103,7 @@ namespace NTwain.Data
         IsoB5 = 29,
         IsoB7 = 30,
         IsoB8 = 31,
-        IsoB9 = 31,
+        IsoB9 = 32,
         IsoB10 = 33,
         JisB0 = 34,
         JisB1 = 35,