diff --git a/rtengine/rt_math.h b/rtengine/rt_math.h
index 7e03a2b6f..1a1c339d9 100644
--- a/rtengine/rt_math.h
+++ b/rtengine/rt_math.h
@@ -29,18 +29,18 @@ namespace rtengine {
 
 
 	template<typename _Tp>
-	inline const _Tp& LIM(const _Tp& a, const _Tp& b, const _Tp& c) {
+	inline const _Tp LIM(const _Tp& a, const _Tp& b, const _Tp& c) {
 		return std::max(b,std::min(a,c));
 	}
 
 	template<typename _Tp>
-	inline const _Tp& ULIM(const _Tp& a, const _Tp& b, const _Tp& c) {
+	inline const _Tp ULIM(const _Tp& a, const _Tp& b, const _Tp& c) {
 		return ((b < c) ? LIM(a,b,c) : LIM(a,c,b));
 	}
 
 	template<typename _Tp>
-	inline const _Tp& CLIP(const _Tp& a) {
-		return LIM(a, static_cast<typeof(a)>(0), static_cast<typeof(a)>(MAXVAL));
+	inline const _Tp CLIP(const _Tp& a) {
+		return LIM(a, static_cast<_Tp>(0), static_cast<_Tp>(MAXVAL));
 		//return ((a)>0.0? ((a)<MAXVAL?(a):MAXVAL):0.0);
 	}
 
diff --git a/rtengine/rtthumbnail.cc b/rtengine/rtthumbnail.cc
index 8527081a7..55599041c 100644
--- a/rtengine/rtthumbnail.cc
+++ b/rtengine/rtthumbnail.cc
@@ -874,6 +874,9 @@ void Thumbnail::getSpotWB (const procparams::ProcParams& params, int xp, int yp,
     if (params.coarse.vflip)       tr |= TR_VFLIP;
 
     // calculate spot wb (copy & pasted from stdimagesource)
+	unsigned short igammatab[256];
+	for (int i=0; i<256; i++)
+	    igammatab[i] = (unsigned short)(255.0*pow(i/255.0,CurveFactory::sRGBGamma));
     int x; int y;
     double reds = 0, greens = 0, blues = 0;
     int rn = 0, gn = 0, bn = 0;