diff --git a/rtengine/procparams.h b/rtengine/procparams.h
index 868a56540..7c2d71aaa 100644
--- a/rtengine/procparams.h
+++ b/rtengine/procparams.h
@@ -218,21 +218,22 @@ public:
         return *this;
     }
 
-    bool operator ==(const Threshold<T> &rhs) const
+    template<typename U = T>
+    typename std::enable_if<std::is_floating_point<U>::value, bool>::type operator ==(const Threshold<U> &rhs) const
     {
         if (_isDouble) {
-            return std::abs(value[0] - rhs.value[0]) < 1e-10
-                   && std::abs(value[1] - rhs.value[1]) < 1e-10
-                   && std::abs(value[2] - rhs.value[2]) < 1e-10
-                   && std::abs(value[3] - rhs.value[3]) < 1e-10;
+            return std::fabs(value[0] - rhs.value[0]) < 1e-10
+                   && std::fabs(value[1] - rhs.value[1]) < 1e-10
+                   && std::fabs(value[2] - rhs.value[2]) < 1e-10
+                   && std::fabs(value[3] - rhs.value[3]) < 1e-10;
         } else {
-            return std::abs(value[0] - rhs.value[0]) < 1e-10
-                   && std::abs(value[1] - rhs.value[1]) < 1e-10;
+            return std::fabs(value[0] - rhs.value[0]) < 1e-10
+                   && std::fabs(value[1] - rhs.value[1]) < 1e-10;
         }
     }
 
-    template<typename U = T, typename = typename std::enable_if<std::is_integral<U>::value>::type>
-    bool operator ==(const Threshold<T> &rhs) const
+    template<typename U = T>
+    typename std::enable_if<std::is_integral<U>::value, bool>::type operator ==(const Threshold<U> &rhs) const
     {
         if (_isDouble) {
             return