diff --git a/rtengine/curves.cc b/rtengine/curves.cc
index aab74a7de..9e3c6527e 100644
--- a/rtengine/curves.cc
+++ b/rtengine/curves.cc
@@ -45,6 +45,42 @@ using namespace std;
 namespace rtengine
 {
 
+bool sanitizeCurve(std::vector<double>& curve)
+{
+    // A curve is valid under one of the following conditions:
+    // 1) Curve has exactly one entry which is D(F)CT_Linear
+    // 2) Number of curve entries is > 3 and odd
+    // 3) curve[0] == DCT_Parametric and curve size is >= 8 and curve[1] .. curve[3] are ordered ascending and are distinct
+    if (curve.empty()) {
+        curve.push_back (DCT_Linear);
+        return true;
+    } else if(curve.size() == 1 && curve[0] != DCT_Linear) {
+        curve[0] = DCT_Linear;
+        return true;
+    } else if((curve.size() % 2 == 0 || curve.size() < 5) && curve[0] != DCT_Parametric) {
+        curve.clear();
+        curve.push_back (DCT_Linear);
+        return true;
+    } else if(curve[0] == DCT_Parametric) {
+        if (curve.size() < 8) {
+            curve.clear();
+            curve.push_back (DCT_Linear);
+            return true;
+        } else {
+            // curve[1] to curve[3] must be ordered ascending and distinct
+            for (int i = 1; i < 3; i++) {
+                if (curve[i] >= curve[i + 1]) {
+                    curve[1] = 0.25f;
+                    curve[2] = 0.5f;
+                    curve[3] = 0.75f;
+                    break;
+                }
+            }
+        }
+    }
+    return false;
+}
+
 Curve::Curve () : N(0), ppn(0), x(nullptr), y(nullptr), mc(0.0), mfc(0.0), msc(0.0), mhc(0.0), hashSize(1000 /* has to be initialized to the maximum value */), ypp(nullptr), x1(0.0), y1(0.0), x2(0.0), y2(0.0), x3(0.0), y3(0.0), firstPointIncluded(false), increment(0.0), nbr_points(0) {}
 
 void Curve::AddPolygons ()
diff --git a/rtengine/curves.h b/rtengine/curves.h
index a9f4b4ace..30fb01102 100644
--- a/rtengine/curves.h
+++ b/rtengine/curves.h
@@ -19,9 +19,12 @@
 #ifndef __CURVES_H__
 #define __CURVES_H__
 
-#include <glibmm.h>
 #include <map>
 #include <string>
+#include <vector>
+
+#include <glibmm.h>
+
 #include "rt_math.h"
 #include "../rtgui/mycurve.h"
 #include "../rtgui/myflatcurve.h"
@@ -42,6 +45,7 @@ using namespace std;
 
 namespace rtengine
 {
+
 class ToneCurve;
 class ColorAppearance;
 
@@ -55,6 +59,8 @@ void setUnlessOOG(T &r, T &g, T &b, const T &rr, const T &gg, const T &bb)
     }
 }
 
+bool sanitizeCurve(std::vector<double>& curve);
+
 namespace curves {
 
 inline void setLutVal(const LUTf &lut, float &val)
diff --git a/rtengine/procparams.cc b/rtengine/procparams.cc
index 526a36765..b07778c55 100644
--- a/rtengine/procparams.cc
+++ b/rtengine/procparams.cc
@@ -87,13 +87,6 @@ Glib::ustring relativePathIfInside(const Glib::ustring &procparams_fname, bool f
     return prefix + embedded_fname.substr(dir1.length());
 }
 
-void avoidEmptyCurve(std::vector<double> &curve)
-{
-    if (curve.empty()) {
-        curve.push_back(FCT_Linear);
-    }
-}
-
 void getFromKeyfile(
     const Glib::KeyFile& keyfile,
     const Glib::ustring& group_name,
@@ -142,7 +135,7 @@ void getFromKeyfile(
 )
 {
     value = keyfile.get_double_list(group_name, key);
-    avoidEmptyCurve(value);
+    rtengine::sanitizeCurve(value);
 }
 
 template<typename T>
diff --git a/rtgui/diagonalcurveeditorsubgroup.cc b/rtgui/diagonalcurveeditorsubgroup.cc
index a022c8650..c23b25f9a 100644
--- a/rtgui/diagonalcurveeditorsubgroup.cc
+++ b/rtgui/diagonalcurveeditorsubgroup.cc
@@ -32,6 +32,8 @@
 #include "diagonalcurveeditorsubgroup.h"
 #include "rtimage.h"
 
+#include "../rtengine/curves.h"
+
 DiagonalCurveEditorSubGroup::DiagonalCurveEditorSubGroup (CurveEditorGroup* prt, Glib::ustring& curveDir) : CurveEditorSubGroup(curveDir)
 {
 
@@ -814,6 +816,8 @@ void DiagonalCurveEditorSubGroup::loadPressed ()
                 }
             }
 
+            rtengine::sanitizeCurve(p);
+
             if (p[0] == (double)(DCT_Spline)) {
                 customCurve->setPoints (p);
                 customCurve->queue_draw ();
diff --git a/rtgui/flatcurveeditorsubgroup.cc b/rtgui/flatcurveeditorsubgroup.cc
index 2cc96a184..27b7ac940 100644
--- a/rtgui/flatcurveeditorsubgroup.cc
+++ b/rtgui/flatcurveeditorsubgroup.cc
@@ -33,6 +33,8 @@
 #include "flatcurveeditorsubgroup.h"
 #include "rtimage.h"
 
+#include "../rtengine/curves.h"
+
 FlatCurveEditorSubGroup::FlatCurveEditorSubGroup (CurveEditorGroup* prt, Glib::ustring& curveDir) : CurveEditorSubGroup(curveDir)
 {
 
@@ -418,6 +420,8 @@ void FlatCurveEditorSubGroup::loadPressed ()
                 }
             }
 
+            rtengine::sanitizeCurve(p);
+
             if (p[0] == (double)(FCT_MinMaxCPoints)) {
                 CPointsCurve->setPoints (p);
                 CPointsCurve->queue_draw ();