>I know energy is quantatized and the visible spectrum is bounded, so there has to be a total amount of wavelengths, right? It's only particles in bound system

>I know energy is quantatized and the visible spectrum is bounded, so there has to be a total amount of wavelengths, right? It's only particles in bound systems that are quantized. For examples electrons in an atom can only have particular energies. But a photon from a rainbow is just flying through free space, so I think it can have any frequency.