Calculates coordinates and colourimetric variables that represent reflectance spectra in a trichromatic chromaticity space.




(required) quantum catch colour data. Can be either the result from vismodel() or independently calculated data (in the form of a data frame with three columns named 's', 'm', 'l', representing a trichromatic viewer).


A data frame of class colspace consisting of the following columns:

  • s, m, l: the quantum catch data used to calculate the remaining variables.

  • x, y: cartesian coordinates for the points in the Maxwell triangle.

  • h.theta: angle theta, in radians, determining the hue of the colour.

  • r.vec: the r vector (saturation, distance from the center).


Maxwell JC. (1970). On color vision. In: Macadam, D. L. (ed) Sources of Color Science. Cambridge, MIT Press, 1872 - 1873.

Kelber A, Vorobyev M, Osorio D. (2003). Animal colour vision - behavioural tests and physiological concepts. Biological Reviews, 78, 81 - 118.

MacLeod DIA, Boynton RM. (1979). Chromaticity diagram showing cone excitation by stimuli of equal luminance. Journal of the Optical Society of America, 69, 1183-1186.


Thomas E. White


data(flowers) <- vismodel(flowers, visual = "apis", achromatic = "l") <- colspace(, space = "tri")