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
Rank in Judo a red-white paneled belt, and judokas who have attained the 9th Dan may wear a solid red belt. In some countries a red belt is used between the white and yellow belts to signify full membership of the judo club or the countries judo association. More commonly the red belt is, however, reserved only for 9th and 10th Dan practitioners. In some countries junior practitioners have an extra system in place to show the progress in between two kyū grades. The sub rank is symbolized by a small piece of fabric on the end of the belt. The colour of