ONE WAY MIRROR GLAZING

Archive of Older Topics Archive - Product Discussions #4
1

I have a project that requires one-way mirror glass (monolithic or by film) from a security room to a loading dock. When one side of the mirror is brightly lit and the other dark, it allows viewing from the darkened side but not vice versa. My problem, the project requires the vice versa. The security room is always brighter than the loading dock. Any ideas? I was considering the pin-dot perforated films used for advertising on buses and storefront.

Thanks,
Wayne

2

Video cameras, and blinds on the window.

3

Roller shades may work better than blinds
They have different weaves that can be used.

4

I really think you can’t get there from there. Glazing and window treatments rely on the physical fact of a difference in light level. You can “see through” all of these treatments from the dark side or more accurately, you can see better through the treatments. Part of it is reflectivity, part of it is light transmittance, and part of it is how wide your iris opens in a darkened area vs. a lighted area. Those decorative dot patterns on vehicle windows work well in daylight. At night, they will be somewhat transparent if the light is on inside the vehicle and the area is poorly lit, one will be able to see inside the vehicle.

You may want to recommend a separate observation room adjacent to the security office. Use of red lights inside the observation room may help.

Video cameras are the best bet for observation where the observer must be unseen. Security people prefer this because the observed never know whether the observer will be there or not.

5

Thanks all.

What I am trying to achieve is not possible without reversing the light levels. An 8:1 light ratio is recommended. I found a good technical bulletin (ATS-125) on the Pilkington web site.
http://www.pilkington.com/resources/ats125swmirropanetm2007827v2.doc

6

Is it possible to just install wall-washing lights above the window to change that level, instead of the entire room lighting system?

7

If the light in the room is bright and the lighting on the outside is minimal I suspect that you will not be able to see much detail outside since your eyes will have adapted to the bright light.

8

Just found this in the January issue of Architectural Record:

http://www.luxar.ch/en/spionspiegel/index.html

They claim a 1:5 lighting ratio (spymirror)

9

Thanks Lynn,

I sourced this product which is a mirror film. Unfortunately, it also must follow the same light level ratio as mirror glass. I confirmed this with the distributor.

SOLYX One Way Privacy Films: SOLYX Mirrored Silver 15% privacy one way film provides one way visibility. It provides daytime privacy. It allows you to see outside, but stops others from seeing in during the day. However, you can see in at night if you have lights on inside. You would still need window coverings at night as you can always see from the darker to the lighter side of the glass.

The example provided is a restroom on the street.

My recommendation is to adjust the light level on both sides to provide a light level ratio of at least 8:1 from brignt (subject) side to dark (observer) side for effective operation.

Thanks to all who responded, but case closed.

For additional information on this subject, go to Pilkington’s website on 4Specs.com, Technical Bulletin ATS-125.

Wayne

10

So I guess no one uses the street restroom at night?