Gamuts and globes: the cartography of color

A device gamut can be visualized as a 3D object in a given color space. The globe is approximately a 3D ellipsoid and has been the motivation for centuries of research in the area of geometric projections. Neither the globe nor a typical device gamut is flat but there are often times when it is useful to examine the globe and device gamuts in 2D. Cartography provides a multitude of geometric projections and terminology that can be used for gamut visualization and mapping. This paper provides examples of how the concepts and principles of cartography can be used for gamut visualization and gamut mapping. The Mercator, Cassini, Bonne, Mollweide, and Sinusoidal projections are used to visualize the sRGB gamut. Finally, a simple example using spherical coordinates is used to demonstrate how gamut projection can be used to implement a specific type of gamut mapping.