--- a/scripts/image/gray.m
+++ b/scripts/image/gray.m
@@ -1,12 +1,35 @@
-function map = gray(number)
+# Copyright (C) 1995 John W. Eaton
+# 
+# This file is part of Octave.
+# 
+# Octave is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2, or (at your option) any
+# later version.
+# 
+# Octave is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with Octave; see the file COPYING.  If not, write to the Free
+# Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 
-  if(nargin == 0)
+function map = gray (number)
+
+# Colormap.
+
+# Written by Tony Richardson (amr@mpl.ucsd.edu) July 1994.
+
+  if (nargin == 0)
     number = 64;
+  elseif (nargin > 1)
+    usage ("gray (number)");
   endif
 
   gr = [0:(number-1)]';
-  
 
-  map = [ gr gr gr ]/(number-1);
+  map = [ gr, gr, gr ] / (number - 1);
 
 endfunction