.........To me, that is not a proper ARC. I don't think an ARC should have any kind of tint. If you can see that it is changing the color of the light, then that means it is reducing the amount of transmitted light, at least in some part of the spectrum. If the outside is reflecting some color back to the outside viewer, then that is visible light that is reflecting instead of letting it pass through to your eye. I.e. reduced transmission of light to the diver.
I would not want a tint that is reducing the visible light transmitted through the lens and into my eyes................
I get what you are saying here and I agree, except that sometimes, depending on the coating and I have to say it don't make sense and I don't know how it works, but you can actually see what seems like brighter colors and more light. Consider the TUSA Paragon mask, it has a sort of dark blue reflective coating on the outside of the lenses, which by all accounts should really cut down the amount of light coming thru, just as you say....but the glass inside has a amber, that is to say looking thru it from the inside, almost bright yellowish tint that makes things appear way brighter to your eye than they are in the ambient light.....if all that makes sense.
Someone else remarked on this thread about how tint {of any kind} has to cut down the amount of light that gets thru, but I am saying that when you put on the Paragon mask and go under the surface, everything appears brighter.
The bad part is that while under water you cant just swap masks fast enough to see the difference quickly like you can for example with sunglasses out of the water. Having both masks I can say that the Paragon definitely makes things appear brighter and clearer as opposed to clear masks. Here is me and my son Jack last month in the Keys...Molasses reef: