The physics of pink – why it isn’t in the rainbow

We see pink when our eyes register a mixture of red and blue light. However, there’s no wavelength corresponding to pink, because the spectrum of light (or electromagnetic radiation) is more like a long line stretching from really low energy radio waves which carry our favourite TV shows, to microwave, infrared, red …your favourite rainbow acronym… violet… ultraviolet, x-rays etc. There’s no red-pink-violet, only red-orange-yellow-green-cyan-blue-violet.