diff --git a/rtengine/improcfun.cc b/rtengine/improcfun.cc
index 74d73f382..ecbd4fa37 100644
--- a/rtengine/improcfun.cc
+++ b/rtengine/improcfun.cc
@@ -5883,7 +5883,7 @@ void ImProcFunctions::chromiLuminanceCurve (PipetteBuffer *pipetteBuffer, int pW
                         editWhatever->v (i, j) = LIM01<float> (LL / 100.f);  // Lab C=f(L) pipette
                     }
 
-                    if (clut) { // begin C=f(L)
+                    if (clut && LL > 0.f) { // begin C=f(L)
                         float factorskin, factorsat, factor, factorskinext;
                         float chromaCfactor = (clcurve[LL * 655.35f]) / (LL * 655.35f); //apply C=f(L)
                         float curf = 0.7f; //empirical coeff because curve is more progressive