How can I see myself as semi-transparent in a window and still see what is behind it?



How can I see myself as semi-transparent in a window and still see what is behind it?

In: Physics

The short answer is that when you “see” something what you’re really seeing is tiny packets of light, called photons, bouncing off something and returning to you, and hitting receptors in your eyes. Your brain then interprets those little packets of light and you see them.

So some surfaces are not 100% reflective, nor 100% transparent, but some combination in between. So let’s say you’re standing at a window, looking a pretty rose bush in your garden. What’s really happening is some light (the sun perhaps) is striking those rose bushes, and bouncing off those rose bushes in all directions, some coming through your window, hitting your eyes, and now you see the bushes.

But that glass isn’t completely clear. Some photons are also coming off YOU, striking the window. Now most pass through. That’s why people on the other side of your window in your garden can see you. But not all do. Some hit the window and bounce back, causing a reflection.


So if you’re looking through a window and seeing a reflection of you AND seeing the rose bush at the same time that’s because what you’re seeing is really a mixture of both of those sources, some of the photons bouncing off your side of the window, showing your reflection, and some coming through.

Light comes from the sun and bounces off the things you can see outside, continuing onto your eyes through the glass so you can see it. Some of that light bounces off your face back onto the glass where it’s reflected again, back into your eyes so you can see it.

Each time the light bounces what you see gets dimmer, so the dim reflected light off you isn’t enough to ‘down out’ the image from outside. If you were inside with the light on, and it was dark outside, then the reflection might be enough to overpower the image from outside.

There are two effects here. First, neither source of light over powers the other. Typically, the sun lights up the background and a much weaker but closer light powers your visage. Second, you can see both because both sources of light make it to your eye. The deconstruction into your awareness that these are two separate images overlaid onto each other is a product of your brain’s analysis. I would venture to say that experience also helps guide you a great deal. You know what it means to see yourself reflected, so your brain anticipates this and easily recognizes it.

The window is bouncing some light back at you, allowing your to see your own reflection. But it is also passing through much more light from the outside, because glass is transparent. Now if it were dark outside and you had a light on inside then almost no light would be coming in from the outside, so you’d see your reflection much stronger.