What is a one way mirror
A one way mirror is really a two way mirror and is most commonly associated with the mirrors you see in the police interrogation rooms on crime drama shows. The police can see the offender and observe the interrogation activity but the offender cannot see the police behind the mirror. One way mirrors are also used for security in retail establishments and for use in teleprompters. A one way (really two way) mirror is known as a half silvered mirror because it contains a semi-transparent film of metal on the first surface of the glass which allows half of the light to be reflected and the other half of the light to be transmitted through the glass. When a one way (two way) mirror is placed in the center of two rooms it provides the appearance of a mirror in a room that is lit and the look of a tinted window in the room that is dark. This is why it is often referred to as a one way mirror by some because it either looks like a mirror or a window.
