Index: trunk/psModules/src/detrend/pmNewNonLinear.c
===================================================================
--- trunk/psModules/src/detrend/pmNewNonLinear.c	(revision 42338)
+++ trunk/psModules/src/detrend/pmNewNonLinear.c	(revision 42448)
@@ -39,5 +39,5 @@
 	    // Calculate correction factor contribution for this pixel.
 	    psF32 flux = image->data.F32[i][j];
-	    psF32 lFlux = log10(flux);
+	    psF32 lFlux = (flux > 1.0) ? log10(flux) : 0.0; // do not introduce NANs for negative flux
 	    
 	    psF32 factor = psSpline1DEval (model, lFlux);