diff --git a/floatimg.h b/floatimg.h
index e7fbf176..3e0a693a 100644
--- a/floatimg.h
+++ b/floatimg.h
@@ -3,7 +3,7 @@
  *			ugly code from tTh
  */
 
-#define		FIMG_VERSION	105
+#define		FIMG_VERSION	106
 
 /*
  *	in memory descriptor
@@ -126,7 +126,7 @@ int     fimg_shift_to_zero(FloatImg *s, FloatImg *d, float coefs[6]);
 
 
 /*	module funcs/geometry.c		*/
-int fimg_equalize_compute(FloatImg *src, void *vptr);
+int fimg_equalize_compute(FloatImg *src, void *vptr, float vmax);
 
 int fimg_mk_gray_from(FloatImg *src, FloatImg*dst, int k);
 int fimg_desaturate(FloatImg *src, FloatImg *dst, int k);
diff --git a/funcs/equalize.c b/funcs/equalize.c
index ca6cccc2..b0b15995 100644
--- a/funcs/equalize.c
+++ b/funcs/equalize.c
@@ -1,6 +1,6 @@
 /*
  *		FLOATIMG
- *	egalisation dinamique approximative
+ *	egalisation dynamique approximative
  *	#coronamaison  Thu 09 Apr 2020 03:37:10 PM CEST
  */
 
@@ -12,25 +12,39 @@
 extern int		verbosity;
 
 /* --------------------------------------------------------------------- */
-int fimg_equalize_compute(FloatImg *src, void *vptr)
+int fimg_equalize_compute(FloatImg *src, void *vptr, float vmax)
 {
 float			minmax[6];
 int			foo;
+float			dr, dg, db;
 
 #if DEBUG_LEVEL
 fprintf(stderr, ">>> %s ( %p )\n", __func__, src);
 #endif
 
+memset(minmax, 0, 6*sizeof(float));
+
 foo = fimg_get_minmax_rgb(src, minmax);
-printf("Rmin  %12.4g    Rmax  %12.4g\n", minmax[0], minmax[1]);
-printf("Gmin  %12.4g    Gmax  %12.4g\n", minmax[2], minmax[3]);
-printf("Bmin  %12.4g    Bmax  %12.4g\n", minmax[4], minmax[5]);
+if (foo) {
+	fprintf(stderr, "err %d get minmax in %s\n", foo, __func__);
+	return foo;
+	}
+
+dr = minmax[1] - minmax[0];
+dg = minmax[3] - minmax[2];
+db = minmax[5] - minmax[4];
+
+printf("Rmin  %12.4g    Rmax  %12.4g    delta %12.4g\n", minmax[0], minmax[1], dr);
+printf("Gmin  %12.4g    Gmax  %12.4g    delta %12.4g\n", minmax[2], minmax[3], dg);
+printf("Bmin  %12.4g    Bmax  %12.4g    delta %12.4g\n", minmax[4], minmax[5], db);
 
 if ( (minmax[0]<0.0) || (minmax[2]<0.0) || (minmax[4]<0.0) ) {
 	fprintf(stderr, "%s: negative value ?\n", __func__);
 	return -4;
 	}
 
+// printf("deltas  %12.4g  %12.4g  %12.4g\n", dr, dg, db);
+
 return 0;
 }
 /* --------------------------------------------------------------------- */
diff --git a/funcs/t.c b/funcs/t.c
index f1b1a96a..20cd8c6e 100644
--- a/funcs/t.c
+++ b/funcs/t.c
@@ -55,7 +55,7 @@ else	{
 	abort();
 	}
 
-foo = fimg_equalize_compute(&src, NULL);
+foo = fimg_equalize_compute(&src, NULL, 666.666);
 fprintf(stderr, "equalize compute --> %d\n", foo);
 
 fimg_destroy(&src);