Color systems are widely used in science, industry, education, and art areas, as the core for any kind of color researches. Researchers use color systems to categorize colors and provide ”specifications” for various colors. However, there are various color systems, differing from each other in the theoretical constructs, experimental tasks used, materials, and application purposes. Three different color system categories are introduced in the present article, and the Natural Color System developed by the Scandinavian Colour Institute is recommended for color uses where the human color perception is the most important considerations.