In color theory, hue is one of the main properties (called color appearance parameters) of a color, defined technically in the CIECAM02 model as "the degree to which a stimulus can be described as similar to or different from stimuli that are described as red, orange, yellow, green, blue, violet," within certain theories of color vision. In painting, a hue is a pure pigment—one without tint or shade (added white or black pigment, respectively). The human brain first processes hues in areas in the extended V4 called globs.