Read the statement by Michael Teeuw here.
Ideal tint for the mirror?
I see a lot of variation in what options are available for two-way mirrors. Different percentages of Variable Light Transmission (VLT) specifically. Has anyone tested different tints/darknesses of glass or film? Is there a resource for recommended VLTs for magic mirrors that I have overlooked? What factors should I consider when deciding on a tint?
the light transmission from the “back” (most mirrors have one side that has more reflection than the other) should be around 20% to get enough light through when the room the mirror is placed in is bright, you might go even higher if the mirror is out in daylight.
The higher transmission of light the more you will see of the monitor itself, even more so when the light in the room gets dimmer. The backlight of monitors will def shine through more the higher percentage you go.
I have a mirror with 3% light transmission, it works fine in a room with no daylight and just a few light sources.
big plus is that the backlight doesn’t show until the room is entirely pitch black.
But! I would suggest a mirror with 12-20% light transmission for most placements.