Equation 2' from Lamb (1995), where S(lambda) is the spectral sensitivity, lambda is the wavelength in nm, and lambda_max is the wavelength of peak sensitivity in nm. A=0.880, B=0.924, C=1.104, D=0.655, a=70, b=28.5, and c =-14.1.
NotesThe above equation produces a fixed template shape on a log wavelength, log frequency, or normalized frequency scale--in accordance with Mansfield's (1985) proposal.
ReferencesLamb, T. D. (1995). Photoreceptor spectral sensitivities: common shape in the long-wavelength region. Vision Research, 35, 3083-3091.
Mansfield, R. J. W. (1985). Primate photopigments and cone mechanisms. In A. Fein, & J. S. Levine (Ed.), The visual system New York: Alan R. Liss.
