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Identify/Detect a Two-Way or Transparent Mirror

A two-way mirror, sometimes called a one-way mirror or transparent mirror, acts like a mirror from one side and like a normal see-through glass from the other. This has been around since some time and many of you may have even noticed the ads from Saint Gobain.

Detecting a Two-Way Mirror
Two-way mirror is great technology, but which can be easily misused. So if you are concerned about a mirror placed in a private room, just do the following checks to find if it is a transparent mirror-

1. A normal mirror will be hung on the wall whereas a transparent mirror will mostly be installed into the wall to hide the room behind it.

2. Turn off the lights and use a light source like a small laser light or flash light against the mirror. If a room is present on the other side, it can be seen by you.
If you don't have any light source, just turn off the lights. You should be able to see the room on the other side of the mirror if it's brighter than your's.

3. Stick your face against the mirror and cup your hands around the eyes to darken the area on your side. The other room should be visible if there is some light there.

4. Tap on the mirror. If there is empty space behind the mirror, a hollow sound should be heard.

5. This is about the so called 'fingernail test' email which has been under circulation since a few years. But this may not work all the time.
Place you fingernail on the surface of the mirror. In a normal mirror, you should be able the see a gap between your nail & its reflection. You may not see that gap in a two-way mirror.
Again, this test will not work against all types of two-way mirrors.

I recommend using the first 4 steps as there is no reliable source for the 5th point.
If there are any other ways to detect this, let everyone know with your comments.
References: Wikihow

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posted by Vijeesh Ravindran, Sunday, December 16, 2007