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) the route by which quantities of oranges were brought from southern ports such as Marseilles to northern France. The family of the Prince of Orange eventually adopted the name and the colour orange in the 1570s. The colour came to be associated with Protestantism, due to participation by the House of Orange on the Protestant side in the French Wars of Religion. One member of the house, William I of Orange, organised the Dutch resistance against Spain, a war that lasted for eighty years, until the Netherlands won its independence. The House's arguably most prominent member, William III of Orange,