Special reflective films provide the “spy mirror” effect which enables the visibility only from one
side, but not from the other.
Spy films are used in the police, at the airports but also in other business and residential spaces
when privacy is needed, including the entertainment industry. On the photo you can see the
reflective films installed by Black Glass in the house of “Big brother”.
The “Big brother” effect
can be achieved by increasing the difference in the light intensity between the two sides. Stronger
light is needed on the observed side than on the other side from which you look. The side with less
light can see everything that is happening on the other side, and the side with stronger light can
see only the mirror.
In case of crystal clean glass, this effect can be achieved with the difference in light intensity,
in the ratio of 250:1. With the films this difference is significantly reduced.
The most popular film used for years for the “spy window effect“ is the silver reflective LLumar
film R20 SR HPR, which enables this effect in the ratio of 7:1. And the most innovative LLumar
product for achieving spy mirror effect is the film RN 07 GR SR HPR, which has the same effect in
the ratio of 2:1!