## Smith & Pokorny (1975) 2-deg cone
fundamentals

### 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 Smith & Pokorny cone fundamentals were obtained
from the following transformations:

,

where ,
and are the Judd,
Vos modified CIE, XYZ 2-deg color matching functions.

See Smith & Pokorny (1975), and p. 615 of Wyszecki
and Stiles (1982).

Note that *L(**λ)*+*M(**λ)* = *V(**λ)*.

The
logarithmic M- and L-cone fundamentals calculated here using the above equations from Smith &
Pokorny (1975) differ slightly from other published tables of their fundamentals in the 3rd
or 4th decimal place < 680 nm (e.g., Wyszecki
and Stiles (1982), Table 2(8.2.5)). The S-cone function, however, differs by up
to ~0.3 log unit from the calculated tables > 600 nm. The authors provided
us with this note about the origin of their S-cone function, for which we thank
them:

Here is the history: “Some time ago we had the Wyszecki & Stiles 1 nm
tabulation of the 1931 CIE CMFs and coordinates scanned into one of our
computers. When we needed 1-nm Vos/Judd data, we used the Vos equations and the
scanned coordinates to derive the coordinates. These yield close but not
identical chromaticity coordinates as the Vos tabulation. The discrepancies are
small. We typed in the Vos and computed the CMFs.”

### References

DeMarco, P., Pokorny, J. & Smith, V. C. (1992). Full spectrum cone
sensitivity functions for X-chromosome linked anomalous trichromats. *Journal
of the Optical Society of America A*, *9*, 1465-1476.

Smith, V. C. & Pokorny, J. (1975). Spectral sensitivity of the foveal
cone photopigments between 400 and 500 nm. *Vision Research*, *15*,
161-171.

Wyszecki, G., & Stiles, W. S. (1982). Color Science: concepts and
methods, quantitative data and formulae. (2nd ed.). New York: Wiley.