Colorimetry derives from the early efforts of Newton, Young, Maxwell, and Helmholtz. In 1901 Pilgrim published a paper in which he quantitatively described a colorimetric system both in trichromatic as well as opponent color format. He appears to be the first to have offered a depiction of the cone-shaped surface of spectral vectors in the space of color fundamentals. (c) 2006 Wiley Periodicals, Inc.