diff --git a/src/Matrix.cc b/src/Matrix.cc
index ea2338b..06928c4 100755
--- a/src/Matrix.cc
+++ b/src/Matrix.cc
@@ -1656,8 +1656,9 @@ NAN_METHOD(Matrix::Threshold) {
     else {
       char *typeString = *typstr;
       char text[] = "\" is no supported binarization technique. "
-        "Use \"Binary\", \"Binary Inverted\", \"Threshold Truncated\", "
-        "\"Threshold to Zero\" or \"Threshold to Zero Inverted\"";
+        "Use \"Binary\" (default), \"Binary Inverted\", "
+        "\"Threshold Truncated\", \"Threshold to Zero\" "
+        "or \"Threshold to Zero Inverted\"";
       char errorMessage[strlen(typeString) + strlen(text) + 2];
       strcpy(errorMessage, "\"");
       strcat(errorMessage, typeString);