--- a/INDEX
+++ b/INDEX
@@ -22,6 +22,7 @@
 Arithmetics
  imadd
  imcomplement
+ imsubtract
 Black and white image functions
  applylut
  bwarea

--- a/NEWS
+++ b/NEWS
@@ -8,6 +8,7 @@
       getrangefromclass
       imadd
       imbothat
+      imsubtract
       iptcheckconn
       iptcheckmap
       iptchecknargin

--- a/inst/imadd.m
+++ b/inst/imadd.m
@@ -26,12 +26,13 @@
 ## in which case @var{out} will be double. Alternatively, the class can be
 ## specified with @var{class}.
 ##
-##@emph{Note 1}: you can force output class to be logical by specifying
+## @emph{Note 1}: you can force output class to be logical by specifying
 ## @var{class}. This is incompatible with @sc{matlab} which will @emph{not} honour
 ## request to return a logical matrix.
 ##
 ## @emph{Note 2}: the values are truncated to the maximum value of the output
 ## class.
+## @seealso{imsubtract}
 ## @end deftypefn
 
 function img = imadd (img, val, out_class = class (img))

new file mode 100644
--- /dev/null
+++ b/inst/imsubtract.m
@@ -0,0 +1,53 @@
+## Copyright (C) 2011 Carnë Draug <carandraug+dev@gmail.com>
+##
+## This program 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 3 of the License, or
+## (at your option) any later version.
+##
+## This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{out} =} imsubtract (@var{a}, @var{b})
+## @deftypefnx {Function File} {@var{out} =} imsubtract (@var{a}, @var{b}, @var{class})
+## Subtract image or constant to an image.
+##
+## If @var{a} and @var{b} are two images of same size and class, @var{b} is subtracted
+## to @var{a}. Alternatively, if @var{b} is a floating-point scalar, its value is subtracted
+## to the image @var{a}.
+##
+## The class of @var{out} will be the same as @var{a} unless @var{a} is logical
+## in which case @var{out} will be double. Alternatively, the class can be
+## specified with @var{class}.
+##
+## @emph{Note 1}: you can force output class to be logical by specifying
+## @var{class}. This is incompatible with @sc{matlab} which will @emph{not} honour
+## request to return a logical matrix.
+##
+## @emph{Note 2}: the values are truncated to the mininum value of the output
+## class.
+## @seealso{imadd}
+## @end deftypefn
+
+function img = imsubtract (img, val, out_class = class (img))
+
+  if (nargin < 2 || nargin > 3)
+    print_usage;
+  endif
+  [img, val] = imarithmetics ("imsubtract", img, val, out_class);
+
+  ## The following makes the code imcompatible with matlab on certain cases.
+  ## This is on purpose. Read comments in imadd source for the reasons
+  if (nargin > 2 && strcmpi (out_class, "logical"))
+    img = img > val;
+  else
+    img = img - val;
+  endif
+
+endfunction