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 by the other organization. Advanced "kyū" levels can be earned by both seniors and juniors (children under the age of about 16) and are signified by wearing belts of various colours other than black. The order of belt colours can vary from dōjō to dōjō, depending on the dōjō's organizational affiliation. For senior players, both the United States Judo Federation (USJF) and ) the United States Judo Association (USJA) specify six "kyū", as listed in the table. The USJA requires "Beginners" (not a kyū) to wear a white belt until they test for yellow belt. The USJA also recommends wearing