can you cancel out light in the same way noise cancelling headphones work?

No problem ! :slight_smile:

Those names you reference ring a bell…its amazing what those old neurons “remember” isnt it ?

As for the bolded parts, I was just trying to be more clear…no intended assholishness here on this end (heh).

We all remember or learn something new once in awhile dont we ?

Though ya know, if you wanna come off as less of an asshole…you need to drop the Butts part of your user name :slight_smile:

Seriously though, nobody in this thread has come off as an asshole as far I am concerned…just a little bit of not quite talking the same language…which I am sure I am as much to blame as anyone else here…

Thanks for taking the time to give us your expert input !

Its been a very bad day here for me, so if you cant make heads or tales of me today…forgive me.

take care

Blll

So, if AR coatings necessarily create constructive interference for some frequencies of light, is that noticeable by the eye? My point is that the glasses sales people will say things like, “It helps driving at night.” It may emphasize some frequency, but there obviously can’t be more photons getting through than were arriving at the surface to begin with. Could it possibly be that these cheap coatings do anything worthwhile in assessment of dark surroundings?

“Helps driving at night” means that bright headlights are made dimmer. In the case of the rearview mirror it amounts to, I believe, nothing more than darkened glass.