You can see through it at least in part because of the tint/opacity effect, where there is more light on the outside than the inside. It's why you can't see through it the other way around (it's reflective, you don't see the astronauts' eyes).
That would imply the result of overlaying Nxylon with this would be gold-colored, not ultra-black..
Right, but less reflective than solid gold, since some of the light is going _though_ instead of bouncing off
So as you make the layer even thinner than the sun protection on those Apollo visors, you have even more light going through, and even less that can bounce off
