diff --git a/rtengine/color.h b/rtengine/color.h
index 049defb70..f2092f530 100644
--- a/rtengine/color.h
+++ b/rtengine/color.h
@@ -298,6 +298,36 @@ public:
         }
     }
 
+    static inline void rgb2hsvtc(float r, float g, float b, float &h, float &s, float &v)
+    {
+        const float var_Min = min(r, g, b);
+        const float var_Max = max(r, g, b);
+        const float del_Max = var_Max - var_Min;
+
+        v = var_Max / 65535.f;
+
+        if (del_Max < 0.00001f) {
+            h = 0.f;
+            s = 0.f;
+        } else {
+            s = del_Max / var_Max;
+
+            if (r == var_Max) {
+                h = (g - b) / del_Max;
+            } else if (g == var_Max) {
+                h = 2.f + (b - r) / del_Max;
+            } else { /*if ( b == var_Max ) */
+                h = 4.f + (r - g) / del_Max;
+            }
+
+            if (h < 0.f) {
+                h += 6.f;
+            } else if (h > 6.f) {
+                h -= 6.f;
+            }
+        }
+    }
+
     /**
     * @brief Convert hue saturation value in red green blue
     * @param h hue channel [0 ; 1]
@@ -312,14 +342,14 @@ public:
     static inline void hsv2rgbdcp (float h, float s, float v, float &r, float &g, float &b)
     {
         // special version for dcp which saves 1 division (in caller) and six multiplications (inside this function)
-        int sector = h;  // sector 0 to 5, floor() is very slow, and h is always >0
-        float f = h - sector; // fractional part of h
+        const int sector = h;  // sector 0 to 5, floor() is very slow, and h is always > 0
+        const float f = h - sector; // fractional part of h
 
         v *= 65535.f;
-        float vs = v * s;
-        float p = v - vs;
-        float q = v - f * vs;
-        float t = p + v - q;
+        const float vs = v * s;
+        const float p = v - vs;
+        const float q = v - f * vs;
+        const float t = p + v - q;
 
         switch (sector) {
             case 1:
diff --git a/rtengine/curves.h b/rtengine/curves.h
index 73cc37ff6..f537bf6c5 100644
--- a/rtengine/curves.h
+++ b/rtengine/curves.h
@@ -1111,29 +1111,28 @@ inline void SatAndValueBlendingToneCurve::Apply (float& r, float& g, float& b) c
 
     assert (lutToneCurve);
 
+    r = CLIP(r);
+    g = CLIP(g);
+    b = CLIP(b);
+
+    const float lum = (r + g + b) / 3.f;
+    const float newLum = lutToneCurve[lum];
+
     float h, s, v;
-    float lum = (r + g + b) / 3.f;
-    //float lum = Color::rgbLuminance(r, g, b);
-    float newLum = lutToneCurve[lum];
-
-    if (newLum == lum) {
-        return;
-    }
-
-    Color::rgb2hsv(r, g, b, h, s, v);
+    Color::rgb2hsvtc(r, g, b, h, s, v);
 
     float dV;
     if (newLum > lum) {
         // Linearly targeting Value = 1 and Saturation = 0
-        float coef = (newLum - lum) / (65535.f - lum);
+        const float coef = (newLum - lum) / (65535.f - lum);
         dV = (1.f - v) * coef;
         s *= 1.f - coef;
     } else {
         // Linearly targeting Value = 0
-        float coef = (newLum - lum) / lum ;
+        const float coef = (newLum - lum) / lum ;
         dV = v * coef;
     }
-    Color::hsv2rgb(h, s, v + dV, r, g, b);
+    Color::hsv2rgbdcp(h, s, v + dV, r, g, b);
 }
 
 }
diff --git a/rtengine/improcfun.cc b/rtengine/improcfun.cc
index c639ffbec..34c43be0e 100644
--- a/rtengine/improcfun.cc
+++ b/rtengine/improcfun.cc
@@ -197,27 +197,22 @@ void proPhotoBlue(float *rtemp, float *gtemp, float *btemp, int istart, int tH,
 void customToneCurve(const ToneCurve &customToneCurve, ToneCurveParams::TcMode curveMode, float *rtemp, float *gtemp, float *btemp, int istart, int tH, int jstart, int tW, int tileSize, PerceptualToneCurveState ptcApplyState) {
 
     if (curveMode == ToneCurveParams::TcMode::STD) { // Standard
+        const StandardToneCurve& userToneCurve = static_cast<const StandardToneCurve&> (customToneCurve);
         for (int i = istart, ti = 0; i < tH; i++, ti++) {
-            const StandardToneCurve& userToneCurve = static_cast<const StandardToneCurve&> (customToneCurve);
-            userToneCurve.BatchApply (
-                    0, tW - jstart,
-                    &rtemp[ti * tileSize], &gtemp[ti * tileSize], &btemp[ti * tileSize]);
+            userToneCurve.BatchApply(0, tW - jstart, &rtemp[ti * tileSize], &gtemp[ti * tileSize], &btemp[ti * tileSize]);
         }
     } else if (curveMode == ToneCurveParams::TcMode::FILMLIKE) { // Adobe like
+        const AdobeToneCurve& userToneCurve = static_cast<const AdobeToneCurve&> (customToneCurve);
         for (int i = istart, ti = 0; i < tH; i++, ti++) {
             for (int j = jstart, tj = 0; j < tW; j++, tj++) {
-                const AdobeToneCurve& userToneCurve = static_cast<const AdobeToneCurve&> (customToneCurve);
-                userToneCurve.Apply (rtemp[ti * tileSize + tj], gtemp[ti * tileSize + tj], btemp[ti * tileSize + tj]);
+                userToneCurve.Apply(rtemp[ti * tileSize + tj], gtemp[ti * tileSize + tj], btemp[ti * tileSize + tj]);
             }
         }
     } else if (curveMode == ToneCurveParams::TcMode::SATANDVALBLENDING) { // apply the curve on the saturation and value channels
+        const SatAndValueBlendingToneCurve& userToneCurve = static_cast<const SatAndValueBlendingToneCurve&> (customToneCurve);
         for (int i = istart, ti = 0; i < tH; i++, ti++) {
             for (int j = jstart, tj = 0; j < tW; j++, tj++) {
-                const SatAndValueBlendingToneCurve& userToneCurve = static_cast<const SatAndValueBlendingToneCurve&> (customToneCurve);
-                rtemp[ti * tileSize + tj] = CLIP<float> (rtemp[ti * tileSize + tj]);
-                gtemp[ti * tileSize + tj] = CLIP<float> (gtemp[ti * tileSize + tj]);
-                btemp[ti * tileSize + tj] = CLIP<float> (btemp[ti * tileSize + tj]);
-                userToneCurve.Apply (rtemp[ti * tileSize + tj], gtemp[ti * tileSize + tj], btemp[ti * tileSize + tj]);
+                userToneCurve.Apply(rtemp[ti * tileSize + tj], gtemp[ti * tileSize + tj], btemp[ti * tileSize + tj]);
             }
         }
     } else if (curveMode == ToneCurveParams::TcMode::WEIGHTEDSTD) { // apply the curve to the rgb channels, weighted
@@ -233,7 +228,7 @@ void customToneCurve(const ToneCurve &customToneCurve, ToneCurveParams::TcMode c
                 rtemp[ti * tileSize + tj] = CLIP<float> (rtemp[ti * tileSize + tj]);
                 gtemp[ti * tileSize + tj] = CLIP<float> (gtemp[ti * tileSize + tj]);
                 btemp[ti * tileSize + tj] = CLIP<float> (btemp[ti * tileSize + tj]);
-                userToneCurve.Apply (rtemp[ti * tileSize + tj], gtemp[ti * tileSize + tj], btemp[ti * tileSize + tj]);
+                userToneCurve.Apply(rtemp[ti * tileSize + tj], gtemp[ti * tileSize + tj], btemp[ti * tileSize + tj]);
             }
         }
     } else if (curveMode == ToneCurveParams::TcMode::PERCEPTUAL) { // apply curve while keeping color appearance constant
@@ -244,7 +239,7 @@ void customToneCurve(const ToneCurve &customToneCurve, ToneCurveParams::TcMode c
                 rtemp[ti * tileSize + tj] = CLIP<float> (rtemp[ti * tileSize + tj]);
                 gtemp[ti * tileSize + tj] = CLIP<float> (gtemp[ti * tileSize + tj]);
                 btemp[ti * tileSize + tj] = CLIP<float> (btemp[ti * tileSize + tj]);
-                userToneCurve.Apply (rtemp[ti * tileSize + tj], gtemp[ti * tileSize + tj], btemp[ti * tileSize + tj], ptcApplyState);
+                userToneCurve.Apply(rtemp[ti * tileSize + tj], gtemp[ti * tileSize + tj], btemp[ti * tileSize + tj], ptcApplyState);
             }
         }
     }