## Stockman, MacLeod & Johnson (1993) 2-deg cone
fundamentals (based on the Stiles & Burch 2-deg CMFs)

### Data key

**Columns**

*Quantal *

- Wavelength (nm)
- log L-cone spectral
sensitivity
- log M-cone spectral
sensitivity
- log S-cone spectral
sensitivity

*Energy *

- Wavelength (nm)
- log L-cone spectral
sensitivity
- log M-cone spectral
sensitivity
- log S-cone spectral
sensitivity

Notes

The proposed 2 deg cone
fundamentals are based on the Stiles & Burch
(1955) 2 deg color matching functions.

From Table A of Stockman, MacLeod and Johnson (1993) *Journal of the
Optical Society of America A*, 10, 2491-2521

Columns 2, 3 and 4: logarithms of proposed S-cone (S),
M-cone (M) and L-cone (L) fundamentals based on the Stiles-Burch (1955) ,
and 2-deg CMFs according to the following
equations:

(λ≤ 525nm)

The S-cone sensitivities have been extended at λ>525 nm by
using the following function:

(where λ is the wavelength in nm).

By adding columns 2 and 3 with weights equal to 0.68273
for L and 0.35235 for M a reasonable approximation to the shape of the CIE
modified *V*_{M}*(**l)* can be obtained.

All coefficients given above have been scaled so that in
energy units the interpolated peak cone sensitivities are equal to 1.

References

Stiles, W. S. & Burch, J. M. (1955). Interim report to the Commission
Internationale de l'Eclairage Zurich, 1955, on the National Physical
Laboratory's investigation of colour-matching. *Optica Acta, 2*, 168-181.

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

Stockman, MacLeod & Johnson (1993) *Journal of the Optical Society of
America A*, 10, 2491-2521