diff --git a/floatimg.h b/floatimg.h
index 49da061..af4fb35 100644
--- a/floatimg.h
+++ b/floatimg.h
@@ -59,6 +59,8 @@ double fimg_timer_set(int whot);
 double fimg_timer_get(int whot);
 
 
+int fimg_mk_gray_from(FloatImg *src, FloatImg*dst, int k);
+
 /*	FIMG files module		*/
 int   fimg_fileinfos(char *fname, int *datas);
 int   fimg_dump_to_file(FloatImg *head, char *fname, int notused);
diff --git a/lib/fimg-2gray.c b/lib/fimg-2gray.c
new file mode 100644
index 0000000..49414cf
--- /dev/null
+++ b/lib/fimg-2gray.c
@@ -0,0 +1,56 @@
+/*
+ *		fimg-2gray.c
+ */
+
+#include  <stdio.h>
+#include  <stdlib.h>
+#include  <unistd.h>
+#include  "string.h"
+
+#include  "../floatimg.h"
+
+extern int verbosity;		/* must be declared around main() */
+
+/* --------------------------------------------------------------------- */
+/*
+ *	floating img MUST be allocated.
+ */
+int fimg_mk_gray_from(FloatImg *src, FloatImg*dst, int k)
+{
+float		kr, kg, kb, kdiv;
+int		nbb, foo;
+
+kr = kg = kb = 1.0;		/* canonic random values */
+kdiv = kr + kg + kb;
+
+/* we must check the validity of our parameters */
+if (FIMG_TYPE_RGB != src->type) {
+	fprintf(stderr, "%s : bad src type %d on %p\n", __func__, 
+				src->type, src);
+	return -8;
+	}
+
+if (FIMG_TYPE_GRAY != dst->type) {
+	fprintf(stderr, "%s : bad dst type %d on %p\n", __func__, 
+				dst->type, dst);
+	return -9;
+	}
+
+/* entering the main processing loop */
+nbb = src->width * src->height;
+
+for (foo=0; foo<nbb; foo++) {
+
+	dst->R[foo] = ( (src->R[foo] * kr) +
+			(src->G[foo] * kg) +
+			(src->B[foo] * kb) ) /
+				kdiv;
+	}
+
+return -1;
+}
+/* --------------------------------------------------------------------- */
+
+
+
+
diff --git a/lib/t.c b/lib/t.c
index a1d5544..b2f2013 100644
--- a/lib/t.c
+++ b/lib/t.c
@@ -30,6 +30,16 @@ for (y=0; y<img->height; y++) {
 	}
 
 return -1;
+}
+/* ---------------------------------------------------------------- */
+
+int essai_2gray(FloatImg *picz, char *outname)
+{
+
+
+
+return -1;
+
 }
 /* ---------------------------------------------------------------- */
 #define W 4000
@@ -56,6 +66,10 @@ foo = fimg_create(&result, W, H, 3);
 
 foo = fimg_add(&dessin, &noise, &result);
 fimg_save_as_pnm(&result, "r_add.pnm",  0);
+
+essai_2gray(&result, "gray.pnm");
+
+
 foo = fimg_sub(&dessin, &noise, &result);
 fimg_save_as_pnm(&result, "r_sub.pnm",  0);
 foo = fimg_mul(&dessin, &noise, &result);