**Columns**

*Quantal *

Logarithmic

- Wavelength (nm)
- log L-cone spectral
sensitivity, log
*L*_{2}*(**λ)* - log M-cone spectral
sensitivity, log
*M*_{2}*(**λ)* - log S-cone spectral
sensitivity, log
*S*_{2}*(**λ)*

*Energy *

Logarithmic

- Wavelength (nm)
- log L-cone spectral
sensitivity, log
*L*_{2}*(**λ)* - log M-cone spectral
sensitivity, log
*M*_{2}*(**λ)* - log S-cone spectral
sensitivity, log
*S*_{2}*(**λ)*

Linear

- Wavelength (nm)
- L-cone spectral
sensitivity,
*L*_{2}*(**λ)* - M-cone spectral
sensitivity,
*M*_{2}*(**λ)* - S-cone spectral
sensitivity,
*S*_{2}*(**λ)*

Notes

2° cone
spectral sensitivities: log *L*_{2}*(**λ) *or log ,
log *M*_{2}*(**λ)* or log and log *S*_{2}*(**λ)* or log at 0.1, 1 or 5 nm steps. The 0.1
and 1 nm functions were obtained by the interpolation of the 5 nm functions
using the cubic spline method. The functions are normalized to peak at
unity at the nearest 0.1 nm step.

The cone spectral sensitivities are defined as linear combinations of the Stiles and Burch (1959) 10-deg CMFs, , and . Their derivation requires a knowledge of the five unknowns, , , , and , in the following equations:

Stockman, Sharpe & Fach (1999) and Stockman and Sharpe (2000) estimated the five unknowns from L- and M-cone spectral sensitivity measurements in single-gene red-green dichromats, S-cone spectral sensitivity measurements in blue cone monochromats and normals, and from existing color matching data. The estimates are =0.010600 for S; =0.168926 and =8.265895 for M and =2.846201 and =11.092490 for L. For the adjustment from 10-deg to 2-deg, it was assumed (i) that the macular pigment density changes from a peak of 0.095 to a peak of 0.35 and (ii) that the peak photopigment optical density changes from 0.38 to 0.50 (for L and M) or from 0.30 to 0.40 (for S). In making the calculations, the Stockman, Sharpe and Fach (1999) lens and macular pigment density spectra were used. The values of , , and , the absolute values of which are unknown, were chosen so that the three functions peak at one.

For further details, see
Stockman, Sharpe & Fach (1999) and Stockman & Sharpe (2000).
Stockman, Sharpe & Fach (1999) were unable to measure S-cone spectral
sensitivity data after 615 nm, after which *S(**λ)* is so small that it
can reasonably, for most purposes, be set to zero.

Stiles, W. S. & Burch, J. M. (1959). NPL
colour-matching investigation: Final report. *Optica Acta*, *6*,
1-26.

Stockman, A., Sharpe, L. T., & Fach, C. C.
(1999). The spectral sensitivity of the human short-wavelength cones. *Vision
Research, 39, *2901-2927.

Stockman, A., & Sharpe, L. T. (2000). Spectral
sensitivities of the middle- and long-wavelength sensitive cones derived from
measurements in observers of known genotype. *Vision Research*,* 40,*
1711-1737.