How to Detect a Two-Way Mirror


Here we go again.

Yesterday, I received an alarming e-mail telling me how to tell if a mirror is one-way or two-way by looking for a gap between an object such as your fingernail placed up against the mirror, and the reflective image of the object. As the myth goes, if there is a gap, the test proves that the mirror is, in fact, one-way. No gap and you're being spied on with a two-way mirror.

The following is a copy of the actual e-mail I received:

"I don't know if this is true but I guess it doesn't hurt to add this to our information what with all the NUTS out there.

The Fingernail Test

Hi There - this is very interesting! A policewoman who travels all over the US and gives seminars and techniques for business women passed this on.

Do you know how to determine if a mirror is 2-way or not?

This is not to scare you, but to make you aware. This is really interesting. Try it with a 'regular' mirror, and you can easily see what the gap means. This is a MUST read!!

When we visit toilets, bathrooms, hotel rooms, changing rooms, etc., how many of you know for sure that the seemingly ordinary mirror hanging on the wall is a real mirror, or actually a 2-way mirror? (i.e., they can see you maybe taking pictures], but you can't see them).

There have been many cases of people installing 2-way mirrors in female changing rooms. It is very difficult to positively identify the surface by just looking at it. So, how do we determine with any amount of certainty what type of mirror we are looking at?

Just conduct this simple test: Place the tip of your fingernail (ball-point pen, eyebrow pencil. any object) against the reflective surface and if there IS A GAP between your fingernail and the image of the nail, then it is a GENUINE mirror.

However, if your fingernail DIRECTLY TOUCHES the image of your nail, then BEWARE, BECAUSE IT IS a 2-WAY MIRROR!

REMEMBER...every time you see a mirror, do the "fingernail test". It doesn't cost you anything, it is simple to do, and it might save you from getting visually raped!"


Ladies: Share this with your girlfriends, sisters, daughters, etc.

Men: Share this with your wives, daughters, daughters-in law, mothers, girlfriends and/or friends.

Everyone...please give this wide dissemination!"


You're probably wondering if this is a true way to tell if the mirror is real, or if it is two-way and being used by some sicko Peeping Tom. I don't think there's anything to back up this theory. I believe the best way to detect a real, one-way mirror would be to take a close look and use common sense. Is it loose? Can you see behind it? Does it appear separate from the wall? What's on the other side?

Whilst it's always a good idea to be on the lookout for your own privacy and safety, if the mirror is actually two-way and someone is getting their cheap thrills, who's to say there aren't other spying devices, such as hidden cameras also? If you're concerned, take a good look at the walls, counter, and ceilings as well as the mirror. If you're uncomfortable in your surroundings, leave immediately.