diff --git a/Fonderie/fonctions.h b/Fonderie/fonctions.h
index eb304f5..ff1fa93 100644
--- a/Fonderie/fonctions.h
+++ b/Fonderie/fonctions.h
@@ -40,6 +40,8 @@ int create_fifo(int nbslot, int w, int h, int t);
  *		funcs in 'sfx.c'
  */
 
+int binarize(FloatImg *pimg, int notused);
+
 int brotche_rand48_a(FloatImg *fimg, float ratio, float mval);
 int brotche_rand48_b(FloatImg *fimg, float ratio, float mval);
 int colors_brotcher(FloatImg *fimg, float fval);
diff --git a/Fonderie/sfx.c b/Fonderie/sfx.c
index e56841f..114de94 100644
--- a/Fonderie/sfx.c
+++ b/Fonderie/sfx.c
@@ -13,12 +13,43 @@
 #include  "fonctions.h"
 
 /* -------------------------------------------------------------- */
-/*	global vars from main
+/*	here are global vars exported by the main module
  */
 extern	int		verbosity;
 
 /* -------------------------------------------------------------- */
+int binarize(FloatImg *pimg, int notused)
+{
+float		mm[6], mR, mG, mB;
+int		foo, x, y;
+float		rgb[3];
 
+#if DEBUG_LEVEL
+fprintf(stderr, ">>> %s ( %p %d )\n", __func__, pimg, notused);
+#endif
+
+foo = fimg_get_minmax_rgb(pimg, mm);
+mR = (mm[1] - mm[0]) / 2.0;
+mG = (mm[3] - mm[2]) / 2.0;
+mB = (mm[5] - mm[4]) / 2.0;
+
+if (verbosity > 1)
+	fprintf(stderr, "%s: %f %f %f\n", __func__, mR, mG, mB);
+
+for (y=0; y<pimg->height; y++) {
+	for (x=0; x<pimg->width; x++) {
+		fimg_get_rgb(pimg, x, y, rgb);
+		if (rgb[0] < mR)	rgb[0] = mm[0];
+		else			rgb[0] = mm[1];
+		if (rgb[1] < mG)	rgb[1] = mm[2];
+		else			rgb[1] = mm[3];
+		if (rgb[2] < mB)	rgb[2] = mm[4];
+		else			rgb[2] = mm[5];
+		}
+	}
+
+return 0;
+}
 /* -------------------------------------------------------------- */
 int brotche_rand48_a(FloatImg *fimg, float ratio, float mval) 
 {