diff --git a/rtengine/improcfun.cc b/rtengine/improcfun.cc
index 3334ae98e..f21d5aaea 100644
--- a/rtengine/improcfun.cc
+++ b/rtengine/improcfun.cc
@@ -316,7 +316,7 @@ void ImProcFunctions::rgbProc (Imagefloat* working, LabImage* lab, LUTf & hltone
 			//float tonefactor = hltonecurve[(0.299f*r+0.587f*g+0.114f*b)];
 			float tonefactor=((r<MAXVAL ? hltonecurve[r] : CurveFactory::hlcurve (exp_scale, comp, hlrange, r) ) + \
 							  (g<MAXVAL ? hltonecurve[g] : CurveFactory::hlcurve (exp_scale, comp, hlrange, g) ) + \
-							  (r<MAXVAL ? hltonecurve[b] : CurveFactory::hlcurve (exp_scale, comp, hlrange, b) ) )/3.0;
+							  (b<MAXVAL ? hltonecurve[b] : CurveFactory::hlcurve (exp_scale, comp, hlrange, b) ) )/3.0;
 			
 			r = (r*tonefactor);
 			g = (g*tonefactor);