diff --git a/Makefile b/Makefile
index fc3f0c5..ecb125c 100644
--- a/Makefile
+++ b/Makefile
@@ -36,6 +36,8 @@ bubblecut.png:		bubblecut.pov Makefile $(POVDEP)
 
 essai.png:		essai.pov Makefile $(POVDEP)
 	povray $(POVOPT) $(DIMS) -K$(CK) -i$< -o$@
+noise.png:		essai.png Makefile
+	convert -verbose -noise 5x15 $< $@
 
 hexabenz.png:		hexabenz.pov Makefile $(POVDEP)
 	povray $(POVOPT) $(DIMS) +K$(CK) -i$< -o$@