Comment by HPsquared

Digital photography then takes us on to subpixels, Bayer filters (https://en.wikipedia.org/wiki/Color_filter_array) and so on. You can also divide the luminance colour parts out. Most image and video compression puts more emphasis on the luminance profile, getting the colour more approximate. The subpixels on a digital camera (or a display for that matter) take advantage of this quirk of human vision.