## MacLeod & Boynton (1979) 2-deg chromaticity coordinates based on the
Stockman & Sharpe (2000) cone fundamentals

### Data key

**Columns**

- Wavelength (nm)
*l*_{MB}*(**λ)*
chromaticity coordinate
*m*_{MB }*(**λ)*
chromaticity coordinate
*s*_{MB}*(**λ*)
chromaticity coordinate

### Notes

The MacLeod-Boynton chromaticity coordinates are defined as:

,
and ,

where ,
and are the three cone spectral sensitivities
scaled so that (i) ,
and (ii) peaks at one. The scaling of the cone
fundamentals given below is relative to each originally being scaled to unity
peak (as in the corresponding cone fundamental tables).

In terms of quanta for the field
size of 2°, *V*_{F,q}(*λ*) = 0.674132 + 0.356683 ,
so that:

and .

For to peak at unity, .

In terms of energy for the field
size of 2°, *V*_{F}(*λ*) = 0.689903 + 0.348322 ,
so that:

and .

For to peak at unity, .

*Note:* The MacLeod-Boynton chromaticity
coordinates calculated from quantal and energy data are identical. The S-cone
coefficient is given to 7 dp, so that peak of is one to 6 dp. The peak is at 418.1 nm.

### References

MacLeod, D. I. A. & Boynton, R. M. (1979). Chromaticity diagram showing
cone excitation by stimuli of equal luminance. *Journal of the Optical
Society of America*, *69*(8), 1183-1186.

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.