diff --git a/file-mat/mat.py b/file-mat/mat.py
index cd05ee8..d26b335 100644
--- a/file-mat/mat.py
+++ b/file-mat/mat.py
@@ -88,7 +88,7 @@ def clear(self):
 
 
 
-    INDEXED, RGB, RGBA,  = range(1, 4)
+    INDEXED, RGB, RGBA,  = range(3)
 
     color_format = namedtuple('color_format', [
         'color_mode',