Colour (US spelling: color) is a phenomenon of light caused by how our eyes detect differing qualities of projected or reflected light color

One aspect of appearance; a stimulus based on visual response to light, consisting of the three dimensions of hue, saturation and lightness.

Complementary Colors: When two or more colors "go together," they are said to be "complementary." This is completely subjective and open to interpretation and differences in opinion. A more exact definition is "any two colors that, when mixed together produce a neutral gray (paint s/pigments) or white (light).