The reason the model of the eye isn't a perfect triangle (as you would expect for three primaries - the three kinds of cones in your eye) is that the frequency response for your cones overlap. There are no frequencies of light that trigger only your green/middle-frequency cones. https://i.imgur.com/Te6XBOB.png
I have to wonder what the sensation of seeing truly "pure" green would be like. What if there were some way to selectively stimulate just the M cones, or to prevent the L cones from being activated?
I think looking at bright red light, with a very low frequency, should temporarily render the red cones less sensitive. Then you'd only get green and blue sensations.
Yes. If you stare at a pure red field on your screen for about 30-60 seconds, then look at a pure green field (or vice-versa), you should see a "super-green" (or "super-red").
I imagine the closest you will get to this "in real life" (rather than a room designed to only contain peak M cone frequencies) is by visiting a tropical rain forest. A common conclusion by tourists is "everything is so... green" due to the over-abundance of rich greens, being far more stimulating than they get from urban and digital exposure.
