A two-way mirror (more accurately termed a "one-way glass") lets viewers see through one side of the mirror while viewers on the other side see only their own reflections. Using reflective film and the proper lighting, you can create a simple two-way mirror without chemicals and hazards used in traditional mirror silvering processes.
Select two rooms with a small space cut between the two. Spaces smaller than 24 inches on a side work best and limit image distortion in the two-way mirror.
Correctly light the two rooms. To create the correct effect, the room in which viewers will see their reflections must be more brightly lit than the room in which viewers will see through the glass. For best results, the room on the glass side should be nearly dark.
Remove the glass or Plexiglas from the picture frame. Carefully clean and dry both sides using the cleaner and cloths.
Cut a sheet of the reflective window film to fit the unframed glass.
Following the manufacturer's instructions, apply the reflective film to the glass, using the squeegee to smooth completely any wrinkles or bubbles.
Reframe the filmed glass with the reflective surface facing outward. Secure the glass to the frame without the included cardboard or other frame backing.
Hang the frame to completely cover the hole.
Two-way mirrors work best in spaces where mirrors would be common, such as in hallways or over sinks. The lighting is critical to the success of the mirror.