04-11-2009, 01:26 PM
I had troubles with snow blinding when I used to ski and to a small extent out on the water , so I've worn the darker ones that don't quite clear completely and also the lighter ones that do clear.
Some lenses have the silver halide disperesd through the lens material.
Some get 'soaked' and it gets absorbed into the outer layer.
Some are coated.
Wouldn't surprise me if they've also figured out how to get it mixed in with the hard coat protection layer.
My last pair had the outer hard coat (scratch resistant coating) fail after a chem flash at a construction site. With the coating gone, the lens manufacturer name became visible across the lens. The tinting still worked, so it wasn't a film.
The photochromic gets darker in the Winter (my current ones are much noticebly darker) and can take quite a while to go clear when going back inside. They change happens quicker in the Summer and I'm convinced they don't get quite so dark when warm.
Some lenses have the silver halide disperesd through the lens material.
Some get 'soaked' and it gets absorbed into the outer layer.
Some are coated.
Wouldn't surprise me if they've also figured out how to get it mixed in with the hard coat protection layer.
My last pair had the outer hard coat (scratch resistant coating) fail after a chem flash at a construction site. With the coating gone, the lens manufacturer name became visible across the lens. The tinting still worked, so it wasn't a film.
The photochromic gets darker in the Winter (my current ones are much noticebly darker) and can take quite a while to go clear when going back inside. They change happens quicker in the Summer and I'm convinced they don't get quite so dark when warm.