CHAPTER 11. HOW ONE-SIDED MIRRORS WORKS.
Ever been to an interview room or interrogation room.There is a mirror in the room. Sitting in
the room one is able to see his own reflection, whereasthe person standing behind in the
darkroom is able to see what’s happening in the nextroom. This is possible because of the
One-sided Mirror in which depending on the light ofrooms its characteristics change from
reflective to translucent.
Usually mirrors are made by silvering, Known as earliersilver nitrate coating was done but
because of the high cost of silver nowadays aluminiumis used. Mirrors work by reflecting light
from the layer of aluminium, but some of the lightcan leak from this layer so there is an opaque
layer at the behind of the mirror to prevent this.
If we instead of making an opaque layer make a translucentlayer at the back then some of the
light will pass through the mirror. This is knownas a half-silvered mirror. If we have a half silver
mirror from both sides we get the mirror we want.That is the one-sided mirror.
The way a one-sided mirror works actually dependson the light available on one side of the
mirror and on the other side. The difference in thelight determines which side of the will be
reflective and which one will be translucent. If thelight in the room you are in is brighter than
that on the other side then you will not be able tosee through the glass, you will only see the
reflection. That is the brighter side will be reflectivewhile the darker side will be translucent. This
happens because the light from the brighter side getsreflected from the half-silvered mirror but
some of the light leaked and because of this leakedlight the other side becomes translucent.
Similar things happen when the room gets darker andone is able to see outside but because of
the brightness outside the view from outside is blocked.
The mirrors used in teleprompter are of similar typeand work on a similar principle. The camera
is in the dark so it is able to record things happeningon the other side whereas the script is on
the brighter side so it is reflected in the mirror.