We’ve all seen these transparent mirrors in crime dramas where the investigator is interviewing a suspect in an interrogation room. It looks like they are alone in the room with just a table and a low-hanging light in between the two. There’s a mirror on the side wall and in a dark room behind that mirror are more detectives watching the scene unfold. Is this just a Hollywood trick or is there science behind this phenomenon?
Every window has a reflective property to it. If you are in your well-lit house at night, trying to look out to the dark world outside, you probably can’t see much more than a reflection of your room. You’ll need to block the light out by cupping your hands around your eyes and placing them on the window so that you can see through the glass. Meanwhile, anyone standing outside in the dark will be able to easily see inside your house. One-way mirror windows use this principle to hide what’s on the dark side of the window.
How do they Work?
Mirrors use a metallic coating of silver or aluminium to reflect the light that tries to pass through the glass. The light bouncing off the coated surface results in you seeing your reflection in the mirror rather than the wall on which it is mounted.
One-way mirror windows use this same coating but only about half of the amount. Half of the light that hits the glass is allowed to pass through, and the other half is reflected. Additionally, the mirror side of the window will be very well lit, while the window side of the mirror (the side that the extra detectives are standing on) will be kept dark. The combination of the metallic coating and lighting creates the effect that there is a mirror on one side and a window on the other.
What are the Uses for One-Way Mirror Windows?
As mentioned already, interrogation rooms are a popular place to use these mirrors. Although there’s no secret anymore about what’s happening on the other side of that mirror, it makes it easier to get a suspect to talk when it appears to be a one-on-one conversation rather than when there are three or four onlookers.
For added privacy, you could have them installed to replace your residential or commercial windows. Their effectiveness will be reduced at night because the mirror side of the window needs good lighting to function properly but it’s an option for added privacy during the day.
You could also outfit your vehicle with one-way mirror windows. As previously mentioned, they will be most effective during the day but can provide added privacy.
How to Clean One-Way Mirror Windows
It’s likely that you’ve only seen one-way mirror windows in interrogation rooms, and hopefully that’s just on TV and not from sitting on the mirror side of the window, but they do have some practical uses outside of the police station. If you’re looking for added privacy, give us a call and we can guide you in finding the right window for your needs.