## MacLeod & Boynton (1979) chromaticity coordinates based on the Smith
& Pokorny (1975) cone fundamentals

### Data key

**Columns**

- Wavelength (nm)
*r*_{MB}*(**λ)*
chromaticity coordinate
*g*_{MB}*(**λ)*
chromaticity coordinate
*b*_{MB}*(**λ*)
chromaticity coordinate

### Notes

MacLeod-Boynton chromaticity
coordinates based on the Smith
& Pokorny cone fundamentals.

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. Traditionally, the Smith & Pokorny and cone fundamentals are already scaled in this
way.

In a space where Cartesian coordinates represent the excitations of the
three cone types involved in color vision, a plane of constant luminance
provides a chromaticity diagram in which excitation of each cone type (at
constant luminance) is represented by a linear scale (horizontal or vertical),
and in which the center-of-gravity rule applies with weights proportional to
luminance (see p. 1183 of MacLeod & Boynton, 1979).

### 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.

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