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
Colour revolution groups, even borrowing the colour orange from the Ukrainian revolution. In November 2005 protesters took to the streets, waving orange flags and banners, to protest what they considered government fraud in recent parliamentary elections. The Azerbaijani colour revolution finally fizzled out with the police riot on 26 November, during which dozens of protesters were injured and perhaps hundreds teargassed and sprayed with water cannons. On February 5, 2013, protests began in Shahbag and later spread to other parts of Bangladesh following demands for capital punishment for Abdul Quader Mollah, who had been sentenced to life imprisonment, and for others convicted