I found a double mirror when I lived. What happened?

The hotel uses double mirrors because the history of this hotel is illegal. Double mirrors are also called two-way mirrors and one-sided perspective glass. Its principle is to add a film of chromium, aluminum or iridium on ordinary glass by vacuum coating.

This glass can reflect most of the projected light back. Hotels are generally one-sided. Regular hotels don't have double mirrors, which is illegal and undesirable.

Test method of hotel mirrors

We measured the thickness of the mirror with our fingers. Let's aim our finger nails at the mirror to see if there is any distance between them. If you see some distance between the two nails, it means that this mirror is a one-sided mirror and an ordinary normal mirror.

And if there is almost no gap between the two nails and they stick together tightly, it means that it is a double mirror, a double mirror, that is, the opposite person can see us, but we can't see the inside. It is very unsafe to install double mirrors in hotel rooms. We'd better check out in time.