You're right that monitor pixels aren't individual wavelengths, but the spectrum of a reproduced image can be very different than the spectrum of the natural im

You're right that monitor pixels aren't individual wavelengths, but the spectrum of a reproduced image can be very different than the spectrum of the natural image. My point was just that you don't want your flat lens harshly filtering that natural image by only operating at 3 highly tuned wavelengths -- that's not going to be enough to capture natural images, despite the fact that we can reproduce them with 3 components.