diff --git a/rtengine/curves.cc b/rtengine/curves.cc
index d39304742..7229e25cb 100644
--- a/rtengine/curves.cc
+++ b/rtengine/curves.cc
@@ -537,7 +537,7 @@ double CurveFactory::centercontrast (double x, double b, double m) {
 			double avg = 0; 
 			//double sqavg = 0;
 			for (int i=0; i<=0xffff; i++) {
-				avg += dcurve[(int)shCurve[CLIP((int)hlCurve[i]*i)]] * histogram[i];
+				avg += dcurve[(int)shCurve[CLIP((int)(hlCurve[i]*i))]] * histogram[i];
 				//sqavg += dcurve[i]*dcurve[i] * histogram[i];
 				sum += histogram[i];
 			}