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) energy for the plants' growth. Similarly the hues of autumn leaves are from the same pigment after chlorophyll is removed. In Europe and America, surveys show that orange is the colour most associated with amusement, the unconventional, extroverts, warmth, fire, energy, activity, danger, taste and aroma, the autumn and Allhallowtide seasons, as well as having long been the national colour of the Netherlands and the House of Orange. It also serves as the political colour of Christian democracy political ideology and most Christian democratic political parties. In Asia it is an important symbolic colour of Buddhism and Hinduism. The colour