Have you ever been in a bathroom, dressing room or other private area with a mirror and got the feeling that someone was watching you? You can check if a mirror is transparent by observing how it is attached and using a few simple techniques to determine if there is a wall behind it. You may have heard of the fingernail test but there is a more accurate way to tell if a mirror is bidirectional or not.
Step
Part 1 of 2: Consider the Location
Step 1. Observe how the mirror is attached
Notice if the mirror appears to be hanging on the wall or is part of the wall itself. If it looks like it's hanging, look behind it and see a wall. If the mirror appears to be part of the wall itself, there is a good chance it is a two-way mirror, which should be mounted into the wall rather than hanging. That way, the person standing on the other side of the wall could observe someone looking in the mirror.
- A two-way mirror is a piece of glass coated with a substance called a micropanel. If you stand on the processed side you will see your shadow but on the unprocessed side it looks like a tinted window.
- If you see that there is a wall behind the mirror, you can be sure that it is nothing more than an ordinary mirror.
Step 2. Check the light
Look around and determine if the lights look unusually bright. If so, you're probably looking in a two-way mirror. However, if the light in the room is relatively dim, and you can't see right through the mirror, it's probably just a standard mirror.
For a two-way mirror to be effective, the light on the mirrored side needs to be 10 times brighter than the light on the other side. If the light is dimmer, you can see through the glass into the observation area
Step 3. Consider where you are
If you're in a public place and in an area where you expect privacy, such as a restroom, it's probably not and it's illegal to have a two-way mirror. On the other hand, two-way mirrors are often used by law enforcement. For example, two-way mirrors are used in interrogation rooms and for lines.
- The use of two-way mirrors is closely related to issues of personal privacy and constitutional rights. Most states have passed additional laws preventing the use of two-way mirrors in restrooms, locker rooms, bathrooms, dressing rooms and hotel rooms. If a location has chosen to use two-way mirrors or surveillance, they need to post signs notifying you.
- Many places, such as gas stations, will use one-way metal mirrors because the glass mirror can be shattered by the user. If the mirror in question is metal, then it is not a two-way mirror.
Part 2 of 2: Checking the Mirror
Step 1. Try peeking through the glass
Press your face into the mirror and cup your hands around your face, creating a dark hallway to block out as much light as possible. When you do this, if the light in the observation room is brighter than the light on the side of your mirror, you will be able to see something behind the glass.
Step 2. Shine a light on the glass
If you're still not sure, turn off the light, then hold the flashlight to the mirror (it can even be "flashlight" on your smartphone). If this is a two-way mirror, the space on the other side will be illuminated and you will be able to see it.
Step 3. Test the sound coming out
Tap the mirror surface with your knuckles. A normal mirror will produce a flat, dull sound, because it is placed in front of the mirror. The observation mirror will produce an open, hollow and echoing sound because there is an open space on the other side.
The knocking sound of a two-way mirror was also described as light or sharp as opposed to the thumping of an everyday mirror
Step 4. Perform a fingernail test
Although not completely accurate, you can use your fingernail to determine if the mirror is the first or second surface of the mirror. Just place your fingernail on the mirror surface. When your fingernail touches the surface of the two mirrors, you cannot touch your reflection; instead, you will see the distance caused by the second layer of glass on the mirror surface. When your finger touches the first surface of the mirror, you can touch your own reflection, as there is no additional layer of glass in between. The first surface of the mirror is very rare, so if you do find one there is likely a very specific reason and it is most likely a two-way mirror. The surface of the two mirrors is your everyday mirror that is everywhere.
- Due to fluctuating factors such as the light and the material that makes up the mirror, it can be very difficult to know if you are actually touching your reflection or not. You may think you're touching the mirror's first surface when you're not.
- Also, it is possible for a bidirectional mirror to be the surface of both mirrors. If other aspects of the situation, such as the mood and the mirror light, have indicated that what you are seeing is a two-way mirror, don't let the fingernail test be the determining factor.
Step 5. Consider extreme measurements by breaking the glass
If this is a regular mirror, it will break and you will see the back of the mirror or a solid wall. If this is a two-way mirror, you will see the room behind the mirror. You should probably only consider this option if you feel threatened or in danger. Breaking the glass will cause damage and endanger safety.
Warning
- There is no definitive test for two-way mirrors. There only needs to be a very small gap in the wall for a hidden camera with a fisheye lens and there won't be any revealing lighting on the other side, or any hollow sound or anything like that to see with your clasped hands. Even if the mirrors were normal, there were plenty of other places to hide the observation tools.
- Keep in mind that most people have no desire to take the risk, trouble, and effort of spying. This includes the exceptions of retail company owners-who often use surveillance technology to prevent employee theft and shoplifting-and a number of government agencies.
