A line from star trek:
"Transparent aluminum???"
"Transparent aluminum???"
http://www.uni-stuttgart.de/aktuelles/presse/2009/116.en.htm...
Deleted comment
That would be a violation of the laws of thermodynamics. It's impossible to make a one way mirror. If you could, you could allow light through from one side, and collect free energy, since one side would be hotter than the other.
And you can't make an active one-way mirror either (at least not without inputting energy) - see http://en.wikipedia.org/wiki/Maxwells_demon
They are not one way. Not in the slightest.
You can turn them around, and they will work unchanged.
They transmit exactly the same amount in both directions.
The only reason they seem to work is that one room is well lit, and the other is dark. So it's hard to see anything from the well lit room.
They are half silvered, so they reflect half, and transmit half. The well lit room then reflects lots of light, but is receiving little light from the dark room.
The dark room reflects little light, but is getting lots from the well lit room.
Hence the references to "imperfect" a few messages back. Pedantry of the kind you're exposing is dangerous (even life threatening) in real life.
If I turn the lights off in my house and you can't see me through an open window will you tell me the open window is a one way window?
Imperfect implies say, 49% of light goes one way and 51% goes the other. Such a mirror does not exist.
And please remember the context (although I think the poster was embarrassed and deleted his original comment), we are talking about making black colors on metal, and he was wondering if it's because it's a one way mirror.
With active one-way mirror I meant one where you have to input energy.