Calculates coordinates and colorimetric variables that represent reflectance spectra in the avian tetrahedral color space.




(required) quantum catch color data. Can be either the result from vismodel() or independently calculated data (in the form of a data frame with four columns name 'u', 's', 'm', 'l', representing the avian cones).


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

  • u, s, m, l: the quantum catch data used to calculate the remaining variables. NOTE: even if visual system is of type V-VIS, the output column will be labeled u.

  • u.r, s.r, m.r, l.r: relative cone stimulation, for a given hue, as a function of saturation. See Stoddard & Prum (2008) for details.

  • x, y, z: cartesian coordinates for the points in the tetrahedral color space.

  • h.theta, h.phi: angles theta and phi, in radians, determining the hue of the color.

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

  • r.max: the maximum r vector achievable for the colour's hue.

  • r.achieved: the relative r distance from the achromatic center, in relation to the maximum distance achievable (r.vec/r.max).


Stoddard, M. C., & Prum, R. O. (2008). Evolution of avian plumage color in a tetrahedral color space: A phylogenetic analysis of new world buntings. The American Naturalist, 171(6), 755-776.

Endler, J. A., & Mielke, P. (2005). Comparing entire colour patterns as birds see them. Biological Journal Of The Linnean Society, 86(4), 405-431.


Rafael Maia


data(sicalis) vis.sicalis <- vismodel(sicalis, visual = "avg.uv") tcs.sicalis <- colspace(vis.sicalis, space = "tcs")