Color theory primary colors work at all is that the imperfect pigments being used have sloped absorption curves, and thus change color with concentration. A pigment that is pure red at high concentrations can behave more like magenta at low concentrations. This allows it to make purples that would otherwise be impossible. Likewise, a blue that is ultramarine at high concentrations appears cyan at low concentrations, allowing it to be used to mix green. Chromium red pigments can appear orange, and then yellow, as the concentration is reduced. It is even possible to mix very low concentrations of the blue mentioned and
Orange (colour) Orange is the colour most easily seen in dim light or against the water, making it, particularly the shade known as safety orange, the colour of choice for life rafts, life jackets or buoys. Highway temporary signs about construction or detours in the United States are orange, because of its visibility and its association with danger. It is worn by people wanting to be seen, including highway workers and lifeguards. Prisoners are also sometimes dressed in orange clothing to make them easier to see during an escape. Lifeguards on the beaches of Los Angeles County, both real and in television