Wavelength

  
            License: Freeware $0.00
            OS: Java,Linux,Mac OS X,Unix,Win2000,Win7 x32,Win7 x64,WinServer,WinVista,WinVista x
            Requirements: Java 1.5+
            Publisher: Canadian Mind Products
            Homepage: http://mindprod.com
          

Wavelength creates Color objects given the wavelength or
the frequency of the light rather than the usual RGB or HSB.

instead of:
Color c = new Color(255, 0, 0);
use the frequency in nanometers, and gamma 0.0. .. 1.0.
(gamma is intensity/brightness.)
Color c = Wavelength.wvColor( 400.0f, 0.80f );
The visible range of the spectrum is 380..780 nanometers.
Smaller is bluer.

or using frequency in Terahertz and gamma 0.0. .. 1.0.
Color c = Wavelength.fColor( 500.0f, 1.0f );
The visible range of the spectrum is 384..789 TeraHertz.
Smaller is redder.

Wavelength does not do much on its own. It is intended to be
incorporated into your own programs.

You might use it to draw a realistic rainbow, or to write
educational Applets about the light spectrum.