The Vos, Estévez and Walraven cone fundamentals are based on the following transformations
where , and are the Stiles & Burch (1955) color matching functions.
Data from Table 1 of Vos. Estévez & Walraven (1990).
The functions have been normalized in the ratio of L:M:S = 0.68:0.34:0.02. They have been "slightly smoothed to remove obvious data noise" (see Vos, Estévez & Walraven, 1990, p. 942).
Click here for information about the unsmoothed functions.
Stiles, W. S., & Burch, J. M. (1955). Interim report to the Commission Internationale de l’Éclairage 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.
Vos, J. J., Estévez, O., & Walraven, P. L. (1990). Improved color fundamentals offer a new view on photometric additivity. Vision Research, 30, 936-943.