The template reflects Dartnall's hypothesis that pigment shapes are invariant when plotted on a wavenumber scale (Dartnall, 1953). The shape of any pigment can then, in principle, be calculated from Dartnall's nomogram simply by adding the pigment's wavenumber of maximum sensitivity to each value.
http://cvision.ucsd.edu/database/text/pigments/dartrhod.htm
I believe these are the curves we are using when calculating on color vision.