Color Color Color (American English), or colour (Commonwealth English), is the characteristic of human visual perception described through color "categories", with names such as red, orange, yellow, green, blue, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the visible spectrum. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them. This reflection is governed by the object's physical properties such as light absorption, emission spectra, etc. By defining a color space, colors can be identified numerically
Rank in Judo Rank in Judo In Judo, improvement and understanding of the art is denoted by a system of rankings split into "kyū" and "dan" grades. These are indicated with various systems of coloured belts, with the black belt indicating a practitioner who has attained a certain level of competence. are ranked according to skill and knowledge of the art. Their rank is indicated by the colour of belt that they wear. There are two broad categories of rank: those who have attained a level of competency at which they are considered worthy of a and who hold grades and those who