diff --git a/layergen.py b/layergen.py
index 6e14cba..9c5ab02 100644
--- a/layergen.py
+++ b/layergen.py
@@ -158,7 +158,7 @@ class mstr_layergen:
             for line in file:
                 linedata = line.split(" ")
                 if len(linedata) > 1: # Make sure we don't break at last line of data file
-                    if linedata[0] == self._tag and linedata[1] == self._value and linedata[2] == ctr:
+                    if linedata[0] == self._tag and linedata[1] == self._value and linedata[2] == res:
                         contrast = int(linedata[3])
                         break