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) problems. Orange also had and continues to have a political dimension. Orange serves as the colour of Christian democratic political ideology, which is based on Catholic social teaching and Neo-Calvinist theology; Christian democratic political parties came to prominence in Europe and the Americas after World War II. In Ukraine in November–December 2004, it became the colour of the Orange Revolution, a popular movement which carried activist and reformer Viktor Yushchenko into the presidency. In parts of the world, especially Northern Ireland, the colour is associated with the Orange Order, a Protestant fraternal organisation and relatedly, Orangemen, marches and other social