When a rainbow is born, no matter whether it is from a prism in a lab or in the sky after a downpour, a plethora of colors emerge from the white light source. Visible light measures between approximately 300 and 700 nanometers of light, and that does not take into account the forms of light we cannot see, of which there are many. The human eye is only developed to see within certain bands of the spectrum, but some animals hunt using light bands we don't notice, like infrared, used by snakes to hunt for small mammals.
The very idea that natural light could produce rainbows goes back to Roger Bacon in the 1200s, but it wasn't until Sir Isaac Newton proved it in the 1600s that the spectrum was defined for the first time, with red, orange, yellow, green, blue, indigo and violet all named colors. Of course, some people are born with a deficiency in the cones in their eyes, resulting in the inability to distinguish between two or more bands of the spectrum, resulting in colorblindness, usually of the blue-green or red-green varieties.
The question is, which one of these colors matches your personality? We have just the way to sort it out. Are you ready to give it a try?