I think our brain would have evolved some sort of post-processing algorithm to deblur the signals from blue cones, if blue was so necessary. But blue comes mos

I think our brain would have evolved some sort of post-processing algorithm to deblur the signals from blue cones, if blue was so necessary. But blue comes mostly as diffused light from the sky. And the effect is especially pronounced in dusk, when blue color floods everything and reduces contrast. That's why yellow glasses help to increase it back and are used in sports and in driving.