diff --git a/spectrum.py b/spectrum.py
index d90598b..023da8d 100755
--- a/spectrum.py
+++ b/spectrum.py
@@ -685,7 +685,7 @@ if intensity != None:
 
         true_intensity_value = ( intensity_stairs.shape[0] - np.polyval( index_polyval , intensity_value ) ) * step
 
-        final_intensity[index] = true_intensity_value
+        final_intensity[index] = np.exp( true_intensity_value )
 
     if verbose:
         print( 'intensity calibration finished' )