--- a/INDEX
+++ b/INDEX
@@ -50,6 +50,7 @@
  cmunique
  colorgradient
  rgb2ycbcr
+ wavelength2rgb
 Display
  rgbplot
 Enhancement and Restoration

--- a/NEWS
+++ b/NEWS
@@ -19,6 +19,7 @@
       iptcheckstrs
       iptnum2ordinal
       normxcorr2
+      wavelength2rgb
 
  ** The following functions have been deprecated in previous releases
     of the image package and have now been removed:

new file mode 100644
--- /dev/null
+++ b/inst/wavelength2rgb.m
@@ -0,0 +1,132 @@
+## Copyright (C) 2011 William Krekeler <WKrekeler@cleanearthtech.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/>.
+
+function RGB = wavelength2rgb( WAVELENGTH, varargin)
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%  function RGB = wavelength2rgb( WAVELENGTH, <INTENSITY_MAX>, <GAMMA> )
+%
+%  Author:     William Krekeler
+%  Date  :     20111031
+%  Synopsis:   convert wavelength in nm into an RGB value set
+%
+%  Returns:    RGB value set on scale of 1:INTENSITY_MAX
+%
+%  Variables: 
+%           all variables encoded as <VAR> are optional, 
+%
+%               WAVELENGTH  = wavelength of input light value in nm
+%                             value can not be a vector
+%
+%               INTENSITY_MAX =  ( default = 255 ) max of integer scale to output values in
+%
+%               GAMMA       = ( default = 0.8 ); value should be 0-1. Controls luminance   
+%
+%  Example Calls:
+%
+%     X = 350:0.5:800;
+%     Y = exp(log(X.^3));   % arbitrary
+%     figure, plot( X, Y )
+%     stepSize = .5*max(diff( X ) );
+%     for n = 1:numel(Y)
+%        RGB = wavelength2rgb( X(n), 1 );
+%          if ( sum( RGB ) > 0 )   % ie don't fill black
+%             hold on, area( (X(n)-stepSize):(stepSize/1):(X(n)+stepSize), ...
+%                repmat( Y(n), 1, numel((X(n)-stepSize):(stepSize/1):(X(n)+stepSize)) ), ...
+%                'EdgeColor', RGB, 'FaceColor', RGB ); hold off
+%          end
+%     end
+% 
+%  Version Update: 20111031 (created)
+%
+%  See also:
+%             put in src
+%
+%  Source:
+%     http://stackoverflow.com/questions/2374959/algorithm-to-convert-any-positive-integer-to-an-rgb-value
+%     http://www.midnightkite.com/color.html per Dan Bruton
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% -- handle inputs
+optargin = size( varargin, 2 );
+
+% set Intensity Max
+if ( optargin > 0 )
+   INTENSITY_MAX = cell2mat(varargin(1));
+else
+   INTENSITY_MAX = 255;
+end
+
+% set the GAMMA value
+if ( optargin > 1 )
+   GAMMA = cell2mat(varargin(2));
+else
+   GAMMA = 0.80;
+end
+
+if ( GAMMA > 1 || GAMMA < 0 )
+   GAMMA = 0.80;
+end
+
+RGB = zeros(3, numel(WAVELENGTH) );  % initialize RGB, each RGB set stored by column
+
+% set the factor
+if ( WAVELENGTH >= 380 && WAVELENGTH < 420 )
+   factor = 0.3 + 0.7*(WAVELENGTH - 380) / (420 - 380);
+elseif ( WAVELENGTH >= 420 && WAVELENGTH < 701 )
+   factor = 1;
+elseif ( WAVELENGTH >= 420 && WAVELENGTH < 701 )
+   factor = 0.3 + 0.7*(780 - WAVELENGTH) / (780 - 700);
+else
+   factor = 0;
+end
+
+% initialize RGB
+if ( WAVELENGTH >=380 && WAVELENGTH < 440 )
+   RGB(1) = -(WAVELENGTH - 440) / (440 - 380);
+   RGB(2) = 0.0;
+   RGB(3) = 1.0;
+elseif ( WAVELENGTH >= 440 && WAVELENGTH < 490 )
+   RGB(1) = 0.0;
+   RGB(2) = (WAVELENGTH - 440) / (490 - 440);
+   RGB(3) = 1.0;
+elseif ( WAVELENGTH >= 490 && WAVELENGTH < 510 )
+   RGB(1) = 0.0;
+   RGB(2) = 1.0;
+   RGB(3) = -(WAVELENGTH - 510) / (510 - 490);
+elseif ( WAVELENGTH >= 510 && WAVELENGTH < 580 )
+   RGB(1) = (WAVELENGTH - 510) / (580 - 510);
+   RGB(2) = 1.0;
+   RGB(3) = 0.0;
+elseif ( WAVELENGTH >= 580 && WAVELENGTH < 645 )
+   RGB(1) = 1.0;
+   RGB(2) = -(WAVELENGTH - 645) / (645 - 580);
+   RGB(3) = 0.0;
+elseif ( WAVELENGTH >= 645 && WAVELENGTH < 781 )
+   RGB(1) = 1.0;
+   RGB(2) = 0.0;
+   RGB(3) = 0.0;
+else
+   RGB(1) = 0.0;
+   RGB(2) = 0.0;
+   RGB(3) = 0.0;
+end
+
+% correct RGB
+RGB = INTENSITY_MAX .* (RGB .* factor) .^GAMMA .* ( RGB > 0 );
+
+return;
+