Yes and yes. The range of colors is limited by our vision, though. A hint at that is that the colors of the rainbow, so pretty in the sky, cover the full range

Yes and yes. The range of colors is limited by our vision, though. A hint at that is that the colors of the rainbow, so pretty in the sky, cover the full range (red to violet) of our vision. If rainbows only contained a subset of the colors we could see, e.g. from yellow to green, we might better assume that this is all that there are. > So wouldn't this be determined first by the frequencies of light (is there IR/UV light to refract?) entering the refractive medium I have photographed IR bands of a rainbow while the visible ones had already faded for example. That was right around sunset, so I suspect it was an extreme form of "red sunset" playing into this.