Light has been observed as a measurable field since the earliest days of man (and perhaps even before that!). Serving as one of the greatest inspirations for art, literature, and other works, the rainbow is the most famous of all light-related phenomena.

Humans have well-developed color vision, but can only see a small portion of the full spectrum; energy values such as ultraviolet and infrared fall outside of visibility. We perceive this small segment as the 7 classical colors of the rainbow; red, orange, yellow, green, blue, indigo, and violet. These colors are the basic building blocks of classical art and color theory.

Rainbows are almost universally associated with happiness, good fortune, joy, and positivity. When viewed from high altitudes, rainbows are seen as fully circular instead of semicircular. Rainbows can occur in double, triple, or supernumerary exotic forms.