Thread by @quaplek

People don’t really understand how frosted glass works. This does us a dis-service.

I think it may have something to do with people intuitively understanding how apertures work. Take for example a gap in a curtain in your living room: this is an aperture.

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We all pretty much understand that when you’re close to the aperture, the curtain gap, you can see lots of what is on the other side.

OTOH, people far away from the aperture, in the street, don’t see much past the gap in the curtains.

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So when someone has frosted glass in their bathroom window (facing the street) and they stand close to it, they can’t see much of the street at all.
But I think because of knowing how curtain gaps work, they assume they are “safe” and the street can see even less of them.

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But sadly that’s wrong.

Frosted glass works like a kind of anti-aperture: being close to the glass actually reveals more of YOU. Being further from the glass reveals less of you.

Why am I saying this?

Because I wish my neighbours across the street knew it.

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They clearly see that the frosted glass stops them seeing the street from the bathroom, and assume it works the other way round.

But that’s not how it works if you’re close to the frosted glass and I’m far away.

Get some blinds please!

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Finally, from physics point of view, there’s some merit, I suppose, to the idea of “anti-aperture”. The frosted glass is acting like many many tiny apertures which are diffracting (diffusing) light that hits them.

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