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I've noticed that on a really tinted window, when looking from farther (and even pretty close just not touching the window), you cannot look inside, but when you put your head so close to the window, that your face is very close (almost touching), then you gain the ability to see inside the window.

I am not asking why a tinted window is reflective from one (bright usually outside) side and can be seen through from the other (darker room). My question is about why this reflective window becomes transparent if you put your head (eyes) very close to the window.

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Question:

  1. On a tinted (reflective) window, why do I need to look from up close to see inside?
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  • $\begingroup$ Please reopen, the linked question does not answer my question. My question is specifically about why you can see through a reflective window if you put your head (eyes) very close to the window, that is otherwise reflective when looking from farter distances. $\endgroup$
    – Árpád Szendrei
    Commented Feb 17 at 23:49
  • $\begingroup$ How does a one-sided glass work? is a different question, but the answer is more or less the same: putting your face up close to the mirror makes this side dark enough that the one-way-mirror effect doesn't dominate. I can see why someone would have closed this as a duplicate (especially with a comment explaining why it's a duplicate), although it's a reasonable question and not totally obvious even given the answer to the other question, so it's probably best that it was reopened. $\endgroup$
    – Peter Cordes
    Commented Feb 18 at 21:26
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    $\begingroup$ Peering closely at a window brings your angle of incidence closer to Brewster's angle, minimizing reflection and enhancing the transparent appearance by allowing more light to pass through the surface of the glass. $\endgroup$
    – Testina
    Commented Feb 18 at 23:58

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Things are called a one-way mirror when the amount of reflected light overwhelms the amount of transmitted light.

When you put your head up to the glass (and maybe put your hands up surrounding your head), you are blocking much more light from your side of the glass. That lowers the reflected light, but not the light transmitted from inside.

If you can block enough light, you prevent the reflections from your side from overwhelming the transmission and you can perceive the signal.

Just as much light is being transmitted when you are not close to the glass, but the signal is so low that you can't pick it out of the much stronger reflection.

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  • $\begingroup$ Ironically, a "one-way mirror" and a "two-way mirror" are the same thing. $\endgroup$
    – Buzz ♦
    Commented Feb 19 at 3:26

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