diff --git a/rtengine/LUT.h b/rtengine/LUT.h
index 29147df8b..6a617f40b 100644
--- a/rtengine/LUT.h
+++ b/rtengine/LUT.h
@@ -93,7 +93,7 @@ class LUT :
 {
 protected:
     // list of variables ordered to improve cache speed
-    unsigned int maxs;
+    int maxs;
     float maxsf;
     // For the SSE routine operator[](vfloat), we just clip float lookup values
     // to just below the max value.