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
Judo rules Judo rules This article describes the rules of judo. The main sections of the article describe the rules that apply to any situation in which judo is practiced, and those rules which apply only in judo competitions. Separate sections describe the history of the rules of judo, provide links to other sources of information on judo rules, and list the references for this article. The scoring rules in use starting in 2017 are as follows: The following rules are no longer in use: Two types of penalties may be awarded. A "shido" (指導; literally "guidance" or "instruction") is awarded for